ben m
Joined: 15 Sep 2002
Posts: 344
Location: UK |
| Week 3 - Computers 2 |
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Ok, lots more questions this week for you to sink your teeth into.
Define the following terms:
Latency
Duplex
Buffer
Define the following Sound Card driver types and their advantages/disadvantages;
MME
Direct X
ASIO
WDM
How may latency be reduced with ASIO/WDM drivers?
Name the primary differences between 'consumer' and 'professional' soundcards.
Define the following hard drive features/specifications and explain their usefulness in a DAW:
Cache
Speed in RPM
ATA Type
Why have many people tended not to use AMD processors in DAWs? Is this down to the processor or the relevant motherboard chipsets?
How may an external 'breakout' box be connected to the host PC? Name 3 different ways and describe the benefits and drawbacks of each protocol.
What is the importance of cluster size for PC based recordings?
Define the Von Neumann model of PC architecture.
Describe each of the following terms of their differences in function;
Point to Point connection
Bus
Network
In a system with a PCI soundcard, is it more desirable to have the graphics card on the AGP or PCI bus?
Name 2 examples of an optical storage format, and their respective capacities.
Explain the importance of each of the following factors in a DAW, and what each factor contributes to a DAW;
Amount of RAM
Hard Drive Space
Processor Speed
Explain the following file systems, their associated OSs' and the capabilities of each File System;
FAT
FAT32
NTFS
What is a 'partition' on a hard drive?
What are the advantages of keeping audio on a seperate partition/drive to program files?
How does a virtual/soft sampler such as Halion utilise the host computers resources?
How many minutes of stereo CD-quality digital audio can be stored in a 1 Gigabyte hard disk partition, approximately?
For a hard disk of 20 Gigabytes capacity or more, what is the most likely backup device, other than another hard disk?
Describe four different areas of application in widespread use and give an example of a popular piece of software in each area.
Describe the main advantages of Firewire compared to SCSI
In relation to computer software;
What is a driver?
What is an extension?
When changing sampling frequency, what happens to the latency?
Excluding the host device, what is the maximum number of devices that may be attached to a SCSI bus?
If it is necessary to reconnect or reconfigure the devices on a SCSI bus what precaution should be taken?
How many terminators would there normally be on a SCSI bus? Where would they be situated?
A system incorporating two devices in addition to the host on a SCSI bus isn’t working correctly. What would you check on the SCSI devices
themselves, assuming they are all switched on?
Macintosh computers running system version 9.0.4 and lower are not very good at playing audio while word processing, whereas IBM PC
compatible computers running Microsoft operating systems are. What is lacking from the Macintosh's operating system?
In a hard disk recording system, which type of disk drive would you expect to allow the most simultaneous tracks to be replayed, a magnetic
hard disk or a magneto-optical disk?
Which is usually thought to offer the most reliable long-term storage, removable magnetic hard disk cartridge or magneto-optical disk?
Compared to digital tape, what is the principal disadvantage of disks for long-term storage?
Explain the advantages of newer 64-bit processors.
Explain why currently 64 bit processors can not be used to their full potential.
Detail the CPUs used in Apple Macs in recent times. |
Mon Mar 21, 2005 8:33 am |
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chemira
Joined: 03 Jan 2005
Posts: 50
Location: Nova Scotia Canada Eh! |
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Week Three Music Technology
Define the following terms:
Latency
Latency also known as delay occurs in the exchange of packets of data from one place to another. In audio, latency is the time that the audio is retrieved from the hard drive then heard or the time that audio is processed then heard with real time effects. Latency also occurs during MIDI as it triggers sounds. Without any form of compensation latency shows up in the delay of a played back track compared to a recorded track. As you play the track it’s latency occurs, then the musician hears the track and plays their part, then the signal is sent into the computer. All of these steps introduce more latency. Some programs compensate for this otherwise you would have to drag the tracks over to reline them up in time after each track is recorded. [1]
Duplex
Duplex Communications means that a sound card can send and receive data at the same time. The term full duplex is a term that is also used which means the same thing. This means that a sound card that is full duplex can playback and record at the same time. [2]
Buffer
A Buffer is a data storage area that allows hardware or software running at different speeds or priorities to coordinate the exchange of data smoothly. An example would be the buffer or storage of data being written to a CDROM. The data must be available as the CD is being written to ensure there is no stopping the recording process. If the buffer is too small the recording process would stop and start repeatedly increasing the error potential rate.[3]
Define the following Sound Card driver types and their advantages/disadvantages;
MME
MME stands for Multi Media Extension and this is a part of windows that sets rules for playback and recording. This is comparatively slow due the driver relying on the Windows Operating system controlling the process. [4]
Direct X
DirectX is a driver format that is written top allow graphical and audio compatibility among a larger number of host applications and programs running on the Microsoft Operating systems. Originally set for the Gaming multi media gaming aspect it has become a more frequently used for compatibility among host application programs and third party developers of enhancement software such as effects. [5]
ASIO
ASIO stands for Audio Streaming Input Output. This was developed by Steinberg to minimize latency on virtual studio Apps. Other hardware and software companies adopted this driver architecture due to it’s low latency. [4]
WDM
WDM Stand for Windows Driver Model is a faster streaming driver that allows the Audio application to process the data without going through the Operating System. This will reduce the latency to a lower figure which will reduce the time to fast times similar to ASIO drivers. [4]
How may latency be reduced with ASIO/WDM drivers?
If the Drivers have been optimized and the processor will not change within the system a way to reduce latency is to reduce the size of the buffer or increase the sampling rate which will decrease the latency. Quote “ You can usually select among buffer sizes of 512, 384, 256, 128 and even 64. This number of samples divided by the sample rate (i.e., 44,100, 96,000, etc) is the latency in microseconds (ms) or thousandths of a second.” Unquote. Therefore as long as the Program and the CPU will support a higher sampling rate the benefit may occur. Not to be ignored there will be a point where the buffer is too small to allow the program to operate smoothly. This adjustment must be done in small amounts and tested to see if the adjustments create stability along with the reduced latency. [6]
Name the primary differences between 'consumer' and 'professional' soundcards.
Professional soundcards will have some form of 1)timing synchronization for other hardware, 2)low latency drivers ASIO/WDM, 3) extremely transparent converters with the digital Audio converters 4) housed in it’s own external breakout or rack mounted box. 5) high signal to noise spec.
1) The timing of the soundcard will need to be accurate with other hardware in the studio paying attention to the type of clocking system used by the studios Timing Master. BNC, SPDIF AES/EBU connectors carry word clock signals to and from the timing slave and master. Accurate Timing systems have low jitter or timing errors.
2) The Low latency drivers and the advantages were addressed in the previous question. The lower the latency the less of a distraction for monitoring and less timing synchronization from played to recorded tracks. [7]
3) The conversion process must be transparent so that the monitored sound is a true representation of the mic’d and direct monitored sound. Each step in the recording chain adds distortion due to the characteristic of the device and it’s design. Some frequencies and transients (fast peak and decay) are difficult to reproduce clearly such as cymbals as they are struck they sound wave swells/rises and collapses rapidly. Any error or lack of accuracy will create a distorted representation of the sound source. Quote “slew rate: Slew rate is the maximum rate at which the DAC output can change, or the maximum rate at which an input signal can change without resulting in an error in the digitized representation of the input signal. For DAC with output amplifiers, the specified slew rate is typically the slew rate of the amplifier.” Unquote. [8]
4) Due to the amount of Potential RF (Radio frequency pulses) and EMF (Electro Motive Forces) From signals and Power distribution inside a computer the converters are best housed outside of a computer in a shielded Case . Some high end audio product utilize double and triple shielding of delicate low level frequencies. This will allow the converters to do their job without any negative influence form the internal PC factors. Now not neglecting the external positioning of the break out box or rack mount box it must not be in an area that is subject to these distortion influences. [ME]
5) The signal to noise ratio must be high to ensure that the audio signal being converted from analog to digital does not “inherit” the noise from the converters. This is known as the self noise of the converter. The usable signal from highest to lowest signal before the signal is lost to the self noise is the dynamic range. [8]
Define the following hard drive features/specifications and explain their usefulness in a DAW:
Cache
A hard drives cache also known as cache memory is a Ram based storage area that is used to store data required for immediate use by the processor from the hard drive. This does not go through the computers RAM prior top processing. The size of this cache can make an improved performance in of the hard drive within the program application being used. [9]
Speed in RPM
Hard drives may have speeds of 5400, 7200, 10 500 and now 15 000 RPM. This higher RPM will assist with the retrieve times and write times while recording data. Errors not withstanding the higher the RPM the better the performance for Recording and Playing back Audio. [11]
ATA Type
An ATA(Advanced Technology Attachment) type Hard drive also know as IDE (Integrated Drive Electronics) is a standard drive type used in most PC’s. [12] The utilization of Serial ATA adds several advantages one being the connection of several drives allowing the Operating system and recording application to run on one drive and the recording and storage of the recorded tracks to be done on another or several other drives. This simultaneous load sharing allows better performance. [13]
Why have many people tended not to use AMD processors in DAWs? Is this down to the processor or the relevant motherboard chipsets?
This has been a debate within the Pro Audio community. Some of the worst chipsets have been produced to cater to the processors from both Intel (Pentium) and VIA (AMD). The chipsets of choice are between Intel and VIA and the stability is becoming a moot point, performance gaps are marginal and most high end pro audio utilize the MAC platform due to it’s stability. Processors are performing at almost identical rates and chipset architecture of north bridge south bridge chipsets is becoming more stable for multi tasking required for Audio.
How may an external 'breakout' box be connected to the host PC? Name 3 different ways and describe the benefits and drawbacks of each protocol.
An external breakout box may be connected via ADAT lightpipe, D sub connector or USB/firewire connections. The ADAT lightpipe is limited in its bit rate or as a sacrifice of channels using higher bit rates. The D sub connector cable breakout boxes can have 24/96Khz data rates butt the cable can only be limited lengths. USB firewire is ever improving and can record 24/96Khz but cable lengths are also restricted.
What is the importance of cluster size for PC based recordings?
Cluster size is the smallest size allocation that Data can be stored in with in the computer. If the cluster size is too large the data that is stored will have wasted space when only a partial size of the cluster is required. If the cluster size is too small then there is a necessity to retrieve more clusters to a given size of total data causing more CPU taxing and storage fragmentation problems.
Define the Von Neumann model of PC architecture.
The Von Neumann model of PC architecture consists of five basic units. The input unit, the output unit, arithmetic logic unit, memory unit and control unit. This model or machine uses a data single storage structure to hold both a asset of instructions on how to perform a computation and the data required or generated by the computation.[14][15]
Describe each of the following terms of their differences in function;
Point to Point connection
A point to point connection is made between two computers utilizing a serial interface. An example would be the connection of a home computer to the WWW accessing other computers information. [16]
Bus
A Bus is a data path that distributes information instructions to any device that is hooked up on that data path. [17]
Network
A network is a connection of several Nodes or data paths that interconnect. [18]
In a system with a PCI soundcard, is it more desirable to have the graphics card on the AGP or PCI bus?
The biggest difference that will be made depending of the placement of a video graphics card will be determined on how the motherboard will assign IRQ’s (Interrupt Request). If the Motherboard has a AGP slot then the IRQ usually assigned to graphics will be a higher priority than the IRQ assigned to the PCI Audio Card. This can cause poor performance to the audio card singe the graphics card takes priority during high CPU loads it will be the last to loose CPU processing. If you place PCI graphics card in the PCI buss you can move it to a slot with a lower IRQ priority. IRQ’s are numbered lowest to highest with priority going to the Lower Number IRQ. [19]
Name 2 examples of an optical storage format, and their respective capacities.
Optical Storage drives consist of a CDROM and a DVDRom drive. These storage devices have capacities of 650 MB to 700MB a DVD can store up to 4.7 GB. [20] [21]
Explain the importance of each of the following factors in a DAW, and what each factor contributes to a DAW;
Amount of RAM
The amount of RAM will assist in the performance of the DAW in that Operating System, and the Program that is being used is held in a rapidly retrievable temporary storage point. This means that if the Program files are held in RAM they can be retrieved without delay. If there is not enough RAM or an inability to properly Manage RAM too much file swapping will occur requiring more processing resources to do the same task if there was More RAM (managed properly). [22]
Hard Drive Space
Hard drive Space is an asset if the drives have been partitioned properly allowing the best seek times with the most area for DATA Storage. Keeping the files in a smaller area allows the Read/Write head to scan or write in a smaller area reducing the time to access data.
Processor Speed
The Processor speed will enable the DAW to calculate faster and with (hopefully) less errors and more data processing capacity. The processor can be the one limiting factor within the DAW as far as Track Recording and Track Playback Capabilities.
Explain the following file systems, their associated OSs' and the capabilities of each File System;
[10]
FAT
FAT is an Acronym for File Allocation Table. Designed by Bill Gates it has gone under several revisions denoting the size of the file cluster FAT 12, and FAT16 referring to the number of Mega bytes in the allocation table. These Storage systems were used from DOS 1 to DOS 6 with a maximum storage capacity of 2GB [10]
FAT32
Fat32 Named because of the 32MB within the storage cluster was introduced on Windows 95B. This larger file allocation size allowed faster retrieval of larger pieces of data and more storage space. Problems arose with larger drives in that there was more wasted space since files of larger than the allocation size would take up several clusters and the final cluster may be only filled by a percentage, thereby wasting the remainder of the clusters storage capability. [10]
NTFS
NTFS utilizes a MFT(Master File Table) to allocate location and file particulars. It does not assign small files into a large cluster and waste space like FAT32 and it groups file DATA on grounds of similar characteristics. [10] [23]
What is a 'partition' on a hard drive?
A partition is a division on a hard drive that would allow the use of Separate Operating systems on the same computer(Dual Boot) or allow the separation of data to group or save different types of information. [24]
What are the advantages of keeping audio on a separate partition/drive to program files?
The Primary Drive can be formatted without affecting the DATA stored on the Partitioned drives although the files are stored on the same Physical disk. [24]
How does a virtual/soft sampler such as Halion utilise the host computers resources?
Halion utilizes the RAM as a storage place for the Soundfonts that are loaded in for retrieval when they are triggered from a keyboard or MIDI file. The processor is used for the note on/off via the host sequencing program. [25]
How many minutes of stereo CD-quality digital audio can be stored in a 1 Gigabyte hard disk partition, approximately?
The formula for determining data space required per track minute is 44.1X16X2X60/8 =10,584,000 bytes. Approximately 94 track minutes of uncompressed CD quality Audio. [26] [27]
For a hard disk of 20 Gigabytes capacity or more, what is the most likely backup device, other than another hard disk?
An Optical drive such as a DVDROM would allow a reasonable amount of storage space 4.7 GB at the best storage/GB cost.
Describe four different areas of application in widespread use and give an example of a popular piece of software in each area.
Many software applications are used in recording and producing audio. Among them are Audio sequencers/ Midi controllers such as SONAR, Wave editors like Sound Forge, Software Synth or Samplers Such as Halion/Giga Sampler and Plugins Live Waves Ultra Maximizer.
Describe the main advantages of Firewire compared to SCSI
Data transfer rates are higher, Cables are common and smaller, More devices can be recognized Firewire drives are hot swappable making external drive changes easy .[28]
In relation to computer software;
What is a driver?
A driver, commonly a DLL (Dynamic Link Library) contains program software that enable a device to run within a host Operating System or Application. The driver is written to modify or include operating instructions required that are not present in the host Operating System or Application. [29]
What is an extension?
A file extension is a three character suffix that allows fast identification of the file type. [30]
When changing sampling frequency, what happens to the latency?
As the sampling frequency is increased the latency reduces. [6]
Excluding the host device, what is the maximum number of devices that may be attached to a SCSI bus?
Up to 15 devices may be attached to a SCSI Bus. [31]
If it is necessary to reconnect or reconfigure the devices on a SCSI bus what precaution should be taken?
You must turn off your computer before disconnecting any SCSI Device. [32]
How many terminators would there normally be on a SCSI bus? Where would they be situated?
There will be two termination for an SCSI bus would situated at the beginning of the bus and at the end of the bus. [33]
A system incorporating two devices in addition to the host on a SCSI bus isn’t working correctly. What would you check on the SCSI devices themselves, assuming they are all switched on?
After checking the terminations on both ends are properly connected; First ensure that the device is being recognized, second ensure the device number is loaded correctly, third ensure device is selected, forth test communications with the device, if that fails fifth reset driver, sixth reload driver and close out configuration utility. [34]
Macintosh computers running system version 9.0.4 and lower are not very good at playing audio while word processing, whereas IBM PC compatible computers running Microsoft operating systems are. What is lacking from the Macintosh's operating system?
Mac OS 9.1 created new enhancements in particular the management of switching between applications was enhanced. [35]
In a hard disk recording system, which type of disk drive would you expect to allow the most simultaneous tracks to be replayed, a magnetic hard disk or a magneto-optical disk?
A magnetic hard disk is faster than the Magnetic Optical drive therefore should be able to render higher recording and playback track counts.[36]
Which is usually thought to offer the most reliable long-term storage, removable magnetic hard disk cartridge or magneto-optical disk?
Digital tape storage is a more cost effective and reliable for a long term storage medium compared to a disk drive. The cost of the tape is the only cost of the storage as opposed to the reading drive, motor controller etc.[36]
Compared to digital tape, what is the principal disadvantage of disks for long-term storage?
A disk drive relies on motor and read head along with controller to access the data while the tape is reliant on the reading drive which can be checked prior to retrieval. [36]
Explain the advantages of newer 64-bit processors.
The main advantage of 64 bit processing is the accuracy of the calculations that are made as audio is recorded and manipulated. Since the accuracy is well in excess of the final resolution the calculations and manipulation of the audio will seem transparent. [37] [38]
Explain why currently 64 bit processors can not be used to their full potential.
Not all applications can render 64 bit calculations and windows is only in a BETA testing mode for this revolutionary processing upgrade. Not all drivers for hardware are written yet either so there will be some waiting to iron out stability issues. [39]
Detail the CPUs used in Apple Macs in recent times.
Apple is presently selling the G5 processor with it’s 64 bit architecture featuring 533 or 600 MHz front side bus for the iMac or up to 1.25 GHz front side bus in the G5 Power Mac (stunned) running Dual 2.5 GHz processors. [40]
Greatgeneral References
http://www.aes.org/
http://whatis.techtarget.com/
[1] http://searchsmb.techtarget.com/sDefinition/0,,sid44_gci212456,00.html
[2] http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci212017,00.html
[3] http://searchsmb.techtarget.com/sDefinition/0,,sid44_gci211713,00.html
[4] http://www.tweakheadz.com/soundcards_page_2.htm
[5] http://searchwin2000.techtarget.com/sDefinition/0,,sid1_gci211958,00.html
[6] http://www.tweakheadz.com/soundcards_for_the_home_studio.htm
[7] http://www.record-producer.com/learn/wordclock-is-it-digital-voodoo-2021.html
[8] http://www.maxim-ic.com/appnotes.cfm/appnote_number/641
[9] http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci211730,00.html
[10] http://vlaurie.com/computers2/Articles/filesystems.htm
[11] http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci211512,00.html
[12] http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci214013,00.html
[13] http://www.pcworld.com/howto/article/0,aid,109366,pg,2,00.asp
[14] http://iiusaedu.com/~murdocca/POCA/slides/Ch01POCA.pdf
[15] http://encyclopedia.laborlawtalk.com/Von_Neumann_architecture
[16] http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci214311,00.html
[17] http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci211718,00.html
[18] http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci212644,00.html
[19] http://searchsmb.techtarget.com/sDefinition/0,,sid44_gci214042,00.html
[20] http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci966110,00.html
[21] http://www6.tomshardware.com/storage/20030207/
[22] http://searchmobilecomputing.techtarget.com/sDefinition/0,,sid40_gci214255,00.html
[23] http://www.pcguide.com/ref/hdd/file/ntfs/arch.htm
[24] http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci212750,00.html
[25] http://www.steinbergcanada.com/products/instruments/halion_3.htm
[26] http://www.teamcombooks.com/mp3handbook/11.htm
[27] http://www.webmasterknowhow.com/html/bytecompare.html
[28] http://home.earthlink.net/~rongonz/home_rec/ide_scsi_etc.html
[29] http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci212002,00.html
[30] http://searchsmb.techtarget.com/sDefinition/0,,sid44_gci212088,00.html
[31] http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci212949,00.html
[32] http://www.adinstruments.com/support/tsupport/scsi.html
[33] http://www.scsita.org/aboutscsi/SCSI_Termination_Tutorial.html
[34] http://www.cyberware.com/documentation/cyscanNT/www/scsi.html
[35] http://www.upenn.edu/computing/help/doc/os/mac/macos91.html
[36] http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci212513,00.html
[37] http://www.softwaretipsandtricks.com/windowsxp/articles/581/1/The-difference-between-64-and-32-bit-processors
[38] http://www.pcmag.com/article2/0,4149,1476776,00.asp
[39] http://www.microsoft.com/windowsxp/64bit/evaluation/upgrade.mspx
[40] http://images.apple.com/powermac/pdf/PowerPCG5_WP_06092004.pdf
Have a better one, I'm tired!! |
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Fri Mar 25, 2005 8:00 pm |
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JohnA
Joined: 20 Jan 2005
Posts: 28
Location: Mid Glamorgan, UK |
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Audio Course
AUMT03
Week 3
JohnA (jalevin)
Define the following terms:
Latency
A measure of how long it takes to get a response from something so it is in essence a delay in signal processing as well as software processing: this is how long it takes for a signal to pass through a device. It is also how long it takes for a result to happen from a command. The command may be a midi command from a keyboard running through software in a computer for example.
Duplex: Full duplex is the ability of a circuit to transmit in either direction at the same time. Half duplex is a transmission over a circuit in either direction but only in one direction at a time.
Buffer: In data transmission, a buffer is a temporary storage location for information that is being sent or received. A temporary memory location for data that is in transit from one device to another device. It is a place that is shared by hardware devices or program processes that operate at different speeds or with differing sets of priorities. The buffer allows each device or process to operate without being held up by the other. It is a “mid point holding place” to support the coordination of separate activities.
Define the following Sound Card driver types and their advantages/disadvantages;
Every hardware device connected to a computer must have a driver. A driver is low-level software that allows Operating Systems and hardware devices to interface with each other. This software works with a computers OS to control a piece of hardware.
MME: Multimedia Extensions: MME has been a standard since Windows 3.1, but it has rapidly been rendered more or less obsolete by DirectX. Probably the only reason to use MME is if you can't get DirectX to work at all, or if you have a very old soundcard for which there are no DirectX drivers available. The most notable disadvantage with MME, apart from the slow performance, is that you can only use one audio application at a time, no matter how many soundcards you have in your computer.
Direct X : Direct X (developed by Microsoft to work originally under Windows 95) allowed programmers to access more directly the sound and graphic capabilities of the computer. This allowed, among other things, faster games. Before the introduction of DirectX, most computer games were written for DOS, since performance in the Windows was very slow - but since the introduction of DirectX, most games are 'Windows native'. Developers of music software immediately saw the potential of DirectX and therefore have supported DirectX since the very first release version, v 1.0. DirectX was not included in Windows95, it was an add-on which you had to install manually - but Windows98 includes DirectX version 5.0. The sound portion of DirectX is called DirectSound. DirectSound drivers are available for nearly all audio cards, but not for all of them.
ASIO: Audio Stream Input / Output. This technology (developed by Steinberg) goes a step further than the standard computer sound card which usually has stereo (two channel) capability only. It allows the user to record and play back audio and midi on multiple-channels when using multi-channel sound cards and recording sequencing software programs. It is also cross platform so other OS can use it. Manufacturers of professional audio sound cards must create an ASIO driver to use with their hardware. The ASIO driver allows the program (Cubase, Sonar etc) to “see” all the I/O connections available on the connected sound card. You can then “assign” them as you want for record / playback with the ASIO compatible software you are using.
WDM: Windows Driver Model created by Microsoft for Windows 98, 2000 Me and XP.
WDM takes some of the work of the device driver that you are using and integrates it into the OS. These portions of code handle all of the low-level buffering management which includes Plug and Play and DMA. Therefore, as the WDM driver channels some of the work into portions of code that are integrated into the OS, it is streamlined (with less code to carry) and becomes far more efficient.
How may latency be reduced with ASIO/WDM drivers?
Described above in “WDM”.
Name the primary differences between 'consumer' and 'professional' soundcards.
Consumer soundcards work at –10dBu whereas professional units work at +4dBu. Consumer soundcard connections are usually unbalanced whereas professional units would have to have balanced connectivity. Audio inputs are also different grades, either consumer or professional grade so they may have unbalanced jack inputs instead of the professional balanced XLR input.
Define the following hard drive features/specifications and explain their usefulness in a DAW:
Cache : A high-speed storage mechanism, either a reserved section of the main memory or it can be in an independent high-speed storage device as in a hard drive. It is a mechanism for speeding up the time it takes to read from or write to a hard disk drive. These days, it is usually included as part of the hard disk drive. The disk cache uses conventional main memory (RAM: Random Access Memory) to speed access time up.This dramatically improves the performance of applications (programs) as accessing data from RAM is thousands of times quicker than trying to access data directly from a hard disk. All recently accessed data from a disk (as well as the adjacent disk sectors) is stored in a memory buffer. When a program need to access data from the disk drive, its first job is to check the disk cache to look and see if the data is there thus making the whole process quicker. The specifications also have different levels: L1 cache (also called primary cach) is built into a microprocessor. L2 cache (also called secondary cache) is cache memory that is “external” to the microprocessor and therefore resides on a separate chip from the microprocessor chip. L2 cache sits between the CPU (Central Processing Unit) and the DRAM (Dynamic Random Access Memory). Both L1 and L2 caches are composed of SRAM (Static Random Access Memory) but L2 caches are much larger. Obviously, in a DAW (Digital Audio Workstation), we can be dealing with large music files (Wav files) in large quantities so quick access is vital.
Speed in RPM : Hard disk drives have a circular hard platter that holds the magnetic medium (unlike floppy drives which have a flexible plastic film). In a hard disk drive, the magnetic recording material is layered onto a high-precision disk made of either aluminum or glass. The platter is then polished to a mirror-type smoothness. When you want to access data from the HDD, the read / write head flies over the disk, never actually touching it. Different HDD have different RPM (Revolutions Per Minute) speeds, with the majority spinning the platter from 3,600rpm to 10,000 rpm. In a DAW, we have to access information quickly, including finding and loading large music files. Again, storage of these files on a HDD allows us this quick access.
ATA Type : Advanced Technology Attachment. A disk drive implementation that integrates the controller (the controller is a small circuit board with chips on it that provide guidance as to exactly how the hard drive stores and accesses data). directly to the memory) and PIO (Programmed input / output), where the CPU manages the information transfer. ATA 1 is more commonly known as IDE. There are several forms of ATA.
ATA: Known also as IDE, supports one or two hard drives, a 16-bit interface and PIO modes 0, 1 and 2.
ATA-2: Supports faster PIO modes (3 and 4) and multiword DMA modes (1 and 2). Also supports logical block addressing (LBA) and block transfers. ATA-2 is marketed as Fast ATA and Enhanced IDE (EIDE).
ATA-3: Minor revision to ATA-2.
Ultra-ATA: Also called Ultra-DMA, ATA-33, and DMA-33, supports multiword DMA mode 3 running at 33 MBps.
ATA/66: A version of ATA proposed by Quantum Corporation, and supported by Intel, that doubles ATA's throughput to 66 MBps.
ATA/100: An updated version of ATA/66 that increases data transfer rates to 100 MBps.
Why have many people tended not to use AMD processors in DAWs? Is this down to the processor or the relevant motherboard chipsets?
Intel Pentium and AMD processors require different motherboards. Many sound cards would not work with the Athlon chipset. However, this is now no the case.
How may an external 'breakout' box be connected to the host PC? Name 3 different ways and describe the benefits and drawbacks of each protocol.
:You can connect an external break out box with a 25-pin D-sub connector cable, with IEEE 1394 cable or over USB 2. connect
Connect the bread out box to the sound card (which is connected to the PCI slot on the motherboard) with a 25 pin D-sub connector cable.
Benefits: Connected internally your connection is solid and permanent. The inputted signal is converted into digital in the breakout box before it is sent to the PCI card. This can result in a cleaner sounding recording.
Drawbacks:
Firewire IEEE 1394 connected from breakout box to PCI card.
Benefits: Fast data transfer. Plug and play. Multiple computers can be networked or share a peripheral without special support - such as software drivers - in the computer or device. It is also cross-platform and supports transfer speeds of up to 800 megabits per second (on machines that support 1394b). Firewire 800 has also doubled the cable length to 15 feet. The Firewire bus can directly power devices up to 45 watts which means that many more Firewire devices can operate without a dedicated power supply than with USB.
Drawbacks: Not all PCs come factory equipped with Firewire ports. Firewire devices are typically more expensive than USB devices.
USB: Connects directly to the USB connector on your DAW.
Benefits: The unit can be placed virtually anywhere making connections via instruments easier (also great for laptop owners). Its instant when you connect (plug and play) and the audio converters can be kept away from the noise inside of the DAW.
Drawbacks: USB uses more of your computer's CPU resources than FireWire so once you start using your computer for other tasks, fewer resources are available to run your USB device, and the slower it works
What is the importance of cluster size for PC based recordings?
Physical formatting is done by the manufacturer to enable logical formatting to take place. Logical formatting places the file system (FAT (File Allocation Table) 16, FAT 32, NTFS etc.) onto the hard drive so that the OS and other data can be installed. When a hard drive is formatted, it is broken down into clusters, which are then in turn broken down into sectors (the OS only views clusters). These clusters can be written in different sizes, typically from 2kb to 8GB, depending on the file management being used (FAT 32 etc.).
The FAT32 system uses small cluster sizes (normally 4Kb) so opting for this will give you more drive space. It does, however, give slightly larger overhead during reading and writing files. The benefit for huge audio files are that large clusters mean fewer read/write operations.
Define the Von Neumann model of PC architecture.
John Von Neumann was the first to spell out the requirements for a general purpose electronic computer. It included three components used in most computers today: CPU, slow to access storage area like a hard drive and a secondary fast access memory (RAM). The machines stored instructions as binary values (creating the stored program concept) and executed instructions sequentially - the processor fetched instructions one at a time and processed them. Today "von Neumann architecture" often refers to the sequential nature of computers based on this model.
Describe each of the following terms of their differences in function;
Point to Point connection: This configuration consists of the basic sending and review station directly connected by a dedicated transmission network (e.g, a single wire or fiber-optic cable). This configuration is often used in a single building to accommodate image transmission from one location to another.
Bus : This network topology has computers connected to a strand of network cabling that is connected to network repeaters at one end and terminated at the other. If you break part of the cable or remove the terminator, all machines on that segment lose communication with the network. 10Base2 was a widely used bus topology network in its day.
Network : A group of interconnected computers connected either by cable or by a wireless system. The computers must be capable of transferring data to and from the network.
In a system with a PCI soundcard, is it more desirable to have the graphics card on the AGP or PCI bus?
It is better to place the graphics card on a separate bus (AGP bus) so that the graphics card does not add noise to the audio that you are recording.
Name 2 examples of an optical storage format, and their respective capacities.
CD has a typical storage capacity of 650Mb and a DVD (single sided) has a storage capacity of 4.7Gb (double this for double sided).
Explain the importance of each of the following factors in a DAW, and what each factor contributes to a DAW;
Amount of RAM : It is important to have as much Ram as you can in a DAW as the more RAM you have, the quicker the access time.
Hard Drive Space : Large hard drive capacity allows you to store more large audio files. Adding an additional hard drive will allow you to store audio files separate from program files, again, allowing for
Processor Speed : This is the clock speed, how many instructions the processor can execute per second (measured in megahertz (MHz). In a DAW, the size of the audio files are so big, we have to use a processor with a high MHz rating to achieve continuity of our work (recording/playback etc.). This speed is what the processor contributes.
Explain the following file systems, their associated OSs' and the capabilities of each File System;
FAT : File Allocation Table. This table is what the OS uses to locate files on a disk. Fragmentation causes the files stored on a disc to be scattered all around the disk. FAT keeps track of all these pieces in the DOS system. FAT’s art stored just after the boot sector. Windows 95 has FAT16 and Windows 98 (and one newer version of Windows 95) is called FAT32.
FAT32: FAT32 available in Windows 95 OSR 2 and Windows 98. FAT32 increases the number of bits used to address clusters and it also reduces the size of each of the clusters. This means that it can support larger hard disk drives (up to 2 terabytes) and it had better storage efficiency (less slack space).
NTFS : NT File System. This is one of the file systems for Windows NT OS (Windows NT also supports the FAT system) and Windows 2000. It is now the standard for Windows XP. NTFS has features to improve reliability, such as transaction logs to help recover from disk failures. To control access to files, you can set permissions for directories and/or individual files. NTFS files are not accessible from other operating systems such as DOS. For any large applications, NTFS supports spanning volumes. This means files and directories can be spread out across several physical disks.
What is a 'partition' on a hard drive?
PARTITION - A “section” of a hard drive. You must create at least one partition to begin using a “new” hard drive, but you can create multiple partitions to keep chunks of your data separate. It is also possible to install multiple OS’s on these multiple partitions. Usually it's just one OS per partition, but some OS’s, like Windows 95/98/Me and Windows NT/2000/XP, for example, are designed to run together in the same partition as long as you use a compatible file system to format the partition.
What are the advantages of keeping audio on a seperate partition/drive to program files?
By keeping audio in a separate partition or on a separate hard drive from your programs, there is less chance that the data of the system files will become corrupt. Faster performance: if all your audio and the program is on the same drive, the drive read/write head has to move from audio file to program to get data. If you have two drives, one read/write head is working on the program while drive 2’s read/write head is getting/recording the files (this is obviously an argument for separate drives and not partitions). Also if you have separate drives, the seek time is less and so latency is lower. Hard drives are read form the outside of the disk first. Again, if you have separate drives you have more “outside” space and so the drive can be read quicker.
How does a virtual/soft sampler such as Halion utilise the host computers resources? This sampler uses “streaming” (transfering data so that it can be used a one continuous stream) under any VST 2 compatible host. With streaming, only the initial portion of the sample is loaded into RAM (the rest of the sample plays as a stream directly from the hard drive. You can adjust the ratio of how much the sample plays from RAM/HDD. Again, using a second hard drive helps here with the sample. If you want to have a number of instruments running at once, extra RAM is essential.
How many minutes of stereo CD-quality digital audio can be stored in a 1 Gigabyte hard disk partition, approximately?
CD’s are recorded at 44.1Khz/16bit stereo. In a one minute recording there is roughly 10Mb of information. There are 1024Mb in a Gigabyte so, 1024 divided by 10Mb = 102.4 minutes.
For a hard disk of 20 Gigabytes capacity or more, what is the most likely backup device, other than another hard disk?
Zip disk will back 20Gb in one go, on CDRW 850Mb you would need 24 discs, DVD Double sided discs can store up to 9.4GB so you would need three of those. USB Flash drives can store up to 1GB so you would need 20! Of them. Go DVD Double Sided.
Describe four different areas of application in widespread use and give an example of a popular piece of software in each area.
Audio / Midi Music Application for recording music in audio and midi forms, Steinberg Cubase SX. Word Processing for storing and manipulating text, Microsoft Word X 10, Computer Graphics for designing visuals, Photoshop software, Computer Video Editing, Pinnacle Liquid.
Describe the main advantages of Firewire compared to SCSI
Firewire supports more devices than SCSI, it is hot pluggable and does not require termination, it sets ID devises automatically, it does not require a computer for data transfer, it has a slightly higher transfer rate that SCSI (firewire has a data transfer rat of up to 1.5gbps, SCSI is 1.2Gbps).
In relation to computer software;
What is a driver? A driver is a small computer program that controls a device. Your printer, mouse, scanner, all these devices need drivers to work with the OS. The drivers for many devices such as keyboards are already built into the OS.
What is an extension?
An extension is an extra feature added to a standard system or programming language.
An example would be In DOS, where one or several letters at the end of a follow a period (dot) and indicate the type of information stored in the file. For example, in the filename EDIT.COM, the extension is COM, which indicates that the file is a command file. (Depending on the operating system, the punctuation separating the extension from the rest of the filename may or may not be considered part of the extension itself.)
When changing sampling frequency, what happens to the latency?
General rule of thumb is the higher the sample rate, the lower the frequency.
Excluding the host device, what is the maximum number of devices that may be attached to a SCSI bus?
The maximum number of devices that can be attached to a SCSI bus is 15.
If it is necessary to reconnect or reconfigure the devices on a SCSI bus what precaution should be taken?
Make sure that you have backed up any data you will need in the future, turn the computer off, always handle the drive by its frame, leave the computer plugged in to an electric outlet with an earth ground (as well as use a grounded static wristband connected to the metal chassis of the computer case). This minimizes the possibility of damage from static discharge.
How many terminators would there normally be on a SCSI bus? Where would they be situated?
There must only be two terminators for each bus segment and these must be placed at the extreme ends of the cabling for each SCSI bus.
A system incorporating two devices in addition to the host on a SCSI bus isn’t working correctly. What would you check on the SCSI devices themselves, assuming they are all switched on?
Cable could be too long, do all the devices have unique SCSI ID’s, if there the proper termination with the last device in the chain,? Sometimes, changing the order of the devices is the chain helps. Also try disabling the built-in termination and attach a physical terminator instead. You can purchase Interex's SCSI Rx. It's an enhanced SCSI diagnostic terminator with LEDs that visually let you see what's going on, such as the TERMPWR wire.
Macintosh computers running system version 9.0.4 and lower are not very good at playing audio while word processing, whereas IBM PC compatible computers running Microsoft operating systems are. What is lacking from the Macintosh's operating system?
Before the Mac OS X, the system was did not have pre-emptive multi-tasking capability. This ability allows the computer to switch from one application to another.
In a hard disk recording system, which type of disk drive would you expect to allow the most simultaneous tracks to be replayed, a magnetic hard disk or a magneto-optical disk?
Magnetic hard disk.
Which is usually thought to offer the most reliable long-term storage, removable magnetic hard disk cartridge or magneto-optical disk?
Optical disks can store data for over 100 years making it more reliable than hard disk storage systems.
Compared to digital tape, what is the principal disadvantage of disks for long-term storage?
HDD are mechanical and will inevitably fail one day so long term storage is not recommended. It is magnetically stored so can easily be damaged.
Explain the advantages of newer 64-bit processors.
64bit processors double the amount of data a CPU can process. It wont make programs run any faster but has the power to dramatically improve the performance of more demanding applications (especially in a DAW where we work with audio files). Long term, it will give programmers much more power to play with so could revolutionize what software will be able to do. 64 bit lets you address more memory. 32 chips can address up to 4GB or memory (Apple G4 up to 2GB). In Windows that is split between the OS and the applications. So the most memory given to any applications is 2GB. A 64-bit processor, on the other hand, can address up to 16 exabytes of memory (that's over 16 billion gigabytes).
Explain why currently 64 bit processors can not be used to their full potential.
64bit processors can not be used to their full potential at the moment because there is no software that can push them to the limits.
Detail the CPUs used in Apple Macs in recent times.
PowerPC G4
PowerPC 7400 (G4 with AltiVec Velocity Engine)
o Power Macintosh G4 Tower
o Power Macintosh G4 Tower MP
o Power Mac G4 Cube
* PowerPC 7410 (G4)
o PowerBook G4 ("Titanium")
o PowerBook G4 ("Titanium")
o Power Macintosh G4 466/533
* PowerPC 7447 (G4)
o PowerBook G4 12.1" (DVI)
o PowerBook G4 15" (Firewire 800)
o PowerBook G4 17" (1.33 GHz)
o Mac mini
* PowerPC 7450 (G4)
o Power Macintosh G4 677/733
o Power Macintosh G4 733/800MP/867 ("Quicksilver")
o PowerBook G4 (Gigabit Ethernet)
o iMac (Flat Panel)
o eMac
* PowerPC 7451 (G4)
o PowerBook G4 ("Titanium") 667
* PowerPC 7455 (G4)
o Power Macintosh G4 800/933/1,000MP ("Quicksilver 2002")
o Power Macintosh G4 867/1000/1250/1420MP (Mirrored Drive Doors)
o PowerBook G4 ("Titanium" 1280x854 screen)667/800
o iBook G4
o iMac (USB 2.0)
o Xserve
o Xserve (Slot Load)
o Xserve (Cluster Node)
o PowerBook G4 17"
o PowerBook G4 15" (DVI)
o PowerBook G4 12.1"
PowerPC G5
* PowerPC IBM 970 (G5) (64-bit)
o Power Macintosh G5 1.6GHz/1.8GHz/dual 1.8GHz/dual 2.0GHz
* PowerPC IBM 970FX (G5)
o Xserve G5 2ghz/dual 2ghz
o Xserve G5 (Cluster Node) dual 2ghz
o Power Macintosh G5 dual 1.8GHz/dual 2.0GHz/dual 2.5GHz
o iMac G5 1.6GHz/1.8GHz
JohnA.
http://www.propellerheads.se/support/rebirth/index.cfm?fuseaction=get_article&article=directx
http://www.cheap56k.com/glossary/Latency.html
http://www.rane.com/par-d.html
http://www.csgnetwork.com/glossaryb.html#buffer
http://www.webopedia.com/TERM/c/cache.html
http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci211963,00.html
http://electronics.howstuffworks.com/hard-disk2.htm
http://www.tdk.com/support/howto/soundcard.html
http://classes.berklee.edu/mbierylo/mtec111_Pages/audio_rec_edit.htm
http://www.pcmus.com/hardrive.htm
http://mixonline.com/mag/audio_steinberg_halion/
http://www.macworld.com/1999/03/features/yosemite_table/
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnwmt/html/audiooverview.asp
http://scsifaq.paralan.com/scsifaqanswers2.html#50
http://www.macgeek.org/articles/199607.html
http://www.fujitsu.com/hk/news/2001/fn640_slimmate_mo.html
http://www.techweb.com/encyclopedia/defineterm.jhtml?term=opticaldisk
http://www.pcworld.com/news/article/0,aid,111508,00.asp
http://www.abcusinc.com/smartDAXcomparison.html#05
JohnA  |
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Sat Mar 26, 2005 9:07 am |
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thx1138
Joined: 07 Jan 2005
Posts: 21
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Week 3 - Computers 2:
Latency:
Latency is the time lag between a request for an action to be performed and the action itself being performed.
(www.bownie.com/guide/glossary/bdc-RG-glossary-L.shtml)
Duplex:
This is the ability of a computer to both send and receive data at the same time.
Buffer:
A buffer is a temporary storage location designed to compensate for a difference in transmission speeds between devices or to hold data when there is a difference in the timing of events.
(www.ceccsystems.com/glossary.htm)
Sound Card Driver types:
MME:
Stands for Multimedia Extension. Typically used on very old versions of windows as default. It is slow as it is controlled directly by the OS. It is old technology and is not good for audio use as it is not optimised for low latency operations. Its usual latency is about 300 to 1000 ms.
ASIO:
Stands for Audio Streaming input/output. Developed for minimising latency with virtual studio applications where multiple streams of audio are processed. Really only utilised in professional audio and music applications. It reduces latency as it offers direct access to hardware, specifically soundcards. It can provide latency as low as 2-10 milliseconds.
Specifically designed for audio use and has good communication between software and devices as it bypasses the OS.
WDM:
Stands for Windows Driver Model with Kernal streaming. A newer lower latency driver that allows an application direct access to the 'Kernal' without going through the windows OS. It is fast like ASIO.
It is often 'translated' from DirectX or MME though this can introduce extra latency. Some WDM drivers can offer latency of under 10 ms making them a good alternative to ASIO.
(www.tweakheadz.com/soundcards-page2-.htm)
(www.pcworld.com.au/index.php)
Latency with ASIO/WDM drivers may be reduced by lowering the size of buffers and lowering the number of buffers.
A professional soundcard is geared toward producing music with your computer and typically would have multiple higher quality inputs and outputs and have no/very little latency.
Hard drive features/specifications and their usefulness in a D(igital)A(udio)W(orkstation):
Cache:
Cache is similar to a buffer. All or part of a file may be read to a cache in the RAM then accessed from there instead of directly from disk.
Cache memory can improve the speed of high performance computers and a large cache would be useful in a DAW as files could be read from the cache as opposed to direct from their location on hard disk, thereby reducing latency.
(www.microsoft.com/hwdev/glossary.htm)
Speed RPM:
The rotation per minute of the hard disk. The faster the speed the faster information can be read from it. Programs can be accessed faster reducing the seek time of the hard drive read write heads. Anything that reduces latency is beneficial to a DAW.
ATA Type:
ATA defines the physical, electrical transport and command protocols for the internal attachment of storage devices. Newer ATA types have a faster data transfer rate therefore latency will be reduced which is advantageous in a DAW.
(www.microsoft.com/hwdev/glossary.htm)
The original AMD atholon CPUs and their associated chipsets refused to work with some soundcards, due to this compatibility issue some DAW users have avoided AMD processors. Many professional soundcards were known not to work with AMD chipsets, plus there was an issue with PCI latency with the VIA chipset that came with the AMD chipsets. These issues have apparently been rectified.
(www.musicwomb.org:81/home/rogers/2PCDAW.html)
A Breakout box is a peripheral attached to a computer that allows many audio inputs and outputs, typically it attached to the computer via Firewire, USB or PCI card.
Connecting via firewire:
Not all computers have a firewire interface but it is faster than USB 1.1, though firewire equipped boxes are liable to be a bit more expensive than USB equipped ones.
Connecting via USB:
USB is advantageous in the fact that it is cheap and compatible over all platforms and most computers generally have more than one USB port. USB 1.1 data transfer rates can result in latency issues but a USB 2.0 port is a lot faster thus negating any latency issues.
Connecting via PCI:
PCI has a high data transfer rate and is very low latency.
Data is stored in clusters on the hard disk. Audio files are quite large so a large cluster size would ensure these files are stored in a continuos block or at least more of the file would be in a continuos block and not fragmented. Data can be accessed more efficiently with minimal fragmentation.
Virtually every electronic computer ever built is rooted in the Von Neumann architecture. The name comes from John Von Neumann who was the first to spell out the requirements for a general-purpose electronic computer.
(www.csupmona.edu/~hnriley/www/VonN.html)
The Von Neumann architecture is a model for a computing machine that uses a single storage structure to hold both the instructions on how to perform a computation and the data required or generated by the computation.
A computer has a Von Neumann architecture if it follows his 'recipe':
Consists of an ALU (arithmetic/logic unit), control unit and I/O devices.
The memory just stores numbers (integers of limited size)
The programs are encoded numerically and stored in the memory along with all data.
One instruction is executed at a time.
Parallel processing is the most common non-Von-Neumann-ness in computers today.
Point to Point:
This is a protocol for communication between two computers using a serial interface. An SCSI bus with only two devices on it (one at each end) can be said to be point to point also.
(I am not very happy with my answer here)
Bus:
A Bus is a computers internal data transmission pathway. Signals can be dropped off or picked up by devices attached to it. Busses exist both in the CPU and connect it to physical memory and peripherals.
Network:
A network is a group of interconnected computers capable of sharing files, resources and exchanging messages. A network can be as small as several computers in the same room in a local area network or as large as a global area network such as the Internet.
It is desirable to have a graphics card attached to an Accelerated Graphics Port in a system with a PCI soundcard as the AGP interface is designed especially for graphics cards and it frees up more data transfer on the PCI bus for the soundcard.
2 examples of optical storage format are: DVD (digital versatile disk) and CD (compact disk).
The capacity of most recordable DVD's is around 4.5 gigabytes though they can have capacities of 4.7, 8.54, 9.4 and 17.08 depending on the disk structure.
Most recordable CD's have a capacity of 650 to 800 megabytes or roughly 74 to 80 minutes of audio.
Amount of RAM:
The more RAM you have the more operational data can be stored for manipulation and the faster that data can be manipulated. Anything that increases the speed of processing would be beneficial to a DAW as it reduces the overall latency.
Hard Drive Space:
Audio files are rather large and some audio applications can be rather large too. The more hard drive space you have the more audio information you can store.
CPU Speed:
With a nice and fast processor a large amount of data can be processed without any system slow-down. Audio software generally requires a lot of processing power so the faster the CPU the better.
FAT:
File Allocation Table: Information about files and their size, location and number of disk sectors used to store a file are kept here. The table information is stored in the data section of a bootable disk, which normally consists of the first 63 sectors.
(www.easydesksoftware.com/glossary.htm)
It enables an operating system to find out where a file is stored on a disk. FAT is the 16 bit system used by MS-DOS and MS-Windows 3.x systems.
FAT32 is the 32-bit system used by MS-Windows 9.x systems.
NTFS is the NT filing system (new technology filing system). Windows 3.x and 9.x can only access files stored on NTFS via a network connection but cannot open NTFS files directly.
It supports long filenames, file system recovery and extremely large storage media. It has many other advantages over other filing systems including improved security and the ability to reconstruct files in the event of hardware failure.
Its is used by Windows NT, 2000, and XP.
(www.5starsupport.com/info/glossary.htm)
(www.easydesksoftware.com/glossary.htm)
(www.pace.ch/cours/glossary.htm)
The advantages of having a separate partition for audio files:
Data Corruption:
Recording audio or streaming large files onto the same drive that contains your system files can cause corruption in your system files.
Slower Fragmentation Rate:
If system files and audio files are kept on separate partitions it will decrease the overall fragmentation rate of the hard disk. If you don't keep installing and uninstalling software on the partition containing program and system files then that partition will become de-fragmented very slowly so you would only need to regularly defrag the audio partition.
There is a disadvantage to have two partitions on the same drive which is the increased read/write head movement from one partition to the other which will, over time, wear out the hard drive due to excessive head movement. A disk with 2 partitions makes the drive work faster and perform a lot of unnecessary head movement. Much better to have 2 separate hard disks which would give:
Faster Performance:
If audio and program files are on the same hard drive it takes time for the read/write heads to move from the system area to where your audio files are. If the heads have to move from one side of the disk to the other this can cause (depending on hard drive time) up to an extra 28ms of latency.
A soft synth like Halion utilises host resources by streaming samples directly from the hard drive instead of loading the entire sample into RAM. For this to work efficiently the first part of every sample streamed from HD has to be held permanently in the RAM to ensure that there is no latency when the required sample is played.
A common source of clicks and pops when using a soft synth such as Halion is not pre-loading enough of each sample into the RAM. A high amount of RAM is required as some soft synths pre-load the entire sample into RAM so it can easily eat up the amount of RAM available.
CD quality sound files are quite large in size, around 10 megabytes per minute of music.
This can be worked out like this:
Channels * Sample Size * Sample Rate = Sound file in bits
8 bits to a byte so divide your answer by 8 and you get the size in bytes of a sound file.
So: 2*44100*16=1411200 bits per second
Divide by 8 to convert that to bytes per second
=176400 bytes per second
Since there are 1024 bytes in a kilobyte we divide that answer by 1024 to work out how many kilobytes per second
176400/1024=172.226 Kilobytes per second
Rounded down lets say 172.2 KB per-second
Since there are 1024 Kilobytes in a megabyte we need to divide that by 1024 again
172.2/1024=0.168 megabytes per second
As there are 60 seconds in a minute we need to multiply this by 60
0.168*60=10.08 megabytes per minute
Since a gigabyte is 1024 megabytes then we need to divide 1024 by 10.08 to work out how many minutes of audio a gigabyte can store which works out at roughly 101 minutes and 30 seconds (give or take a few seconds) so approximately 100 minutes.
For a hard disk of over 20 gigabytes magnetic tape would more than likely be used to store a backup as opposed to another hard drive. Magnetic tape is quite cheap which is an advantage, recordable dvds could be used but wouldn't really be very cost effective compared to magnetic tape.
Four different areas of application in widespread use for audio purposes are Samplers (Nemesys Gigasampler), Sequencers (Steinberg Cubase), Audio Editors (Sonic Foundry Soundforge) and Mastering software (IK Multimedia T-Racks).
Firewire vs. SCSI
Megabytes per second transfer rate Maximum devices
Firewire 50 63
Firewire 800 100 63
SCSI standard 80 16
SCSI 320 320 16
(I noticed that Firewire is measured in mega BITs per second and SCSI is measured in mega BYTES)
Ultra SCSI is now standard.
(www.backupbook.com/OSHard_Drives/AASCSI_Basics_.html)
Firewire has a higher transfer rate than standard SCSI but newer versions of SCSI have up to 320 megabytes per second transfer rates whereas even Firewire 800 is only 100 megabytes per second.
Firewire however supports far more devices, a maximum of 63 whereas SCSI only supports 16.
Also with SCSI you have to restart your computer to connect a new device or disconnect an already connected device and Firewire supports hot swapping and plug and play. Hot swapping means the computer need not be turned off when disconnecting/connecting devices. Plug and play compatibility defines a piece of hardware that has built in initialising capabilities. The OS automatically recognises its presence and adds it to the system configuration eliminating previously needed drivers and installation discs.
Driver:
A driver is a piece of software that interacts with and controls particular devices or software applications. When information is passed from one type of device to another, usually the electrical and mechanical requirements of the devices are different. The driver is used to translate information sent to a device so that the device can properly process it. It basically tells the computer how to use the device/software.
Extension:
The last characters in a file name that follow the dot are the extension. It indicates the type of information stored in a file and so the computer can identify the file so it knows which application is used to open it.
When the sampling frequency is increased the latency decreases.
"Doubling the sampling frequency leads to a doubling in the overall data rate of a digital audio system and a consequent halving in storage time."
(p207- Sound Recording: An Introduction 4th edition, by Francis Rumsey and Tim McCormick)
When reconnecting or reconfiguring a SCSI device switching off your computer is a necessary precaution as SCSI devices do not support hot swapping like USB or Firewire does.
Terminators on a SCSI bus:
Two terminators must be present on a SCSI bus as a pulse travelling along the SCSI bus will 'reflect' from any part of the bus that is different to the rest of it. These reflections can cause the original pulse to be distorted and corrupted causing data loss. The terminators are added to minimise/prevent reflections from the ends of the bus.
The terminators must be present at the beginning of the bus and at the end of the bus and must occur within 4 inches of the physical ends of the bus.
(www.scsita.org/aboutscsi/SCSI_Termination_Tuturial.html#TERMINATION)
If a system incorporating 2 devices in addition to the host on a SCSI bus isn't working properly and the SCSI devices are switched on I would:
Check they are connected correctly to the SCSI bus.
Check the terminators at either end of the bus.
Check for SCSI device conflicts (they must have a unique Id)
Mac operating systems before the introduction of Mac OSX weren't so good at pre-emptive multitasking which enables a computer to successfully switch between several applications that are running at the same time. Before OSX the Mac OS used co-operative multitasking which means that one application could end up hogging the CPU's processing power to the detriment of other applications running.
As far as hard drives go in a hard disk recording system Magnetic hard disks would be better as they are faster and perform better than magneto-optical disks.
(www.viewz.com/shoppingguide/storageprint.htm)
Magneto-optical disk is a better choice for long term storage over magnetic disk simply because magnet-optical disks have a longer shelf life.
Compared to digital tape the principal disadvantages of magnetic disk for long term storage is that a disk has more mechanical and moving parts than a tape which makes them more prone to wear.
The advantages of a 64-bit processor are that it would be able to process more information in the same amount of time as a 32-bit processor and would be capable of accessing a lot more memory.
Currently, 64 bit processors cannot be used to their full potential as there aren't many applications optimised and recompiled to take advantage of the new 64 bit capabilities.
Some Mac CPU's that have been used in recent times:
G4 400 MHz CPU
G4 1.25 GHz power PC CPU
G5 1.8 GHz single CPU
G5 1.8 GHz dual CPU
G5 2.0 GHz dual CPU
G5 2.5 GHz dual CPU |
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Sat Mar 26, 2005 7:59 pm |
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rachelh
Joined: 16 Jan 2005
Posts: 35
Location: Trinidad WI |
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Latency
The Term Latency describes the actual delay in terms of processing a signal or processing software. Latency therefore is the time taken for a signal to pass through to an electronic device [the time taken for a device to respond to the request / command at hand] or the time taken for a request to be processed and applied. Propagation delay, describes the initial delay that will occur that is, the time it will take the signal to pass through a signal processing box, thus propagation delay contributes to latency, in general, the higher the latency of the device, the longer it would take for processing. [1] [2]
Duplex
The term duplex describes a simultaneous transmission of independent data over two circuits in both directions. It is also referred to as full duplex or two way, while half- duplex or one- way refers to the transmission over a circuit that is only capable to process one signal in either direction but, only processing one direction at a time. [1]
Buffer
The term buffer describes an area in the memory of a computer that is used to store temporary data, which is being sent or received in the process of data transmission. [1]
Define the following Sound Card driver types and their advantages/disadvantages;
MME
MME stands for Multimedia Extension; it is an audio and video driver for the Windows Operating System. MME is one of the older sound drivers as it was the first Microsoft OS that provided a universal API that worked with the soundcard hardware the same way which is an advantage of the driver’s capabilities. It is an API soundcard driver, which is used by the audio software to access the hardware, which proved to be an advantageous step in the sound card driver movement. However, the high latency of the driver, which was well over 500 milliseconds, that ultimately forced the issue for more updated driver systems such as WDM [Windows driver Model] which proved to be the most disadvantageous characteristic of this driver. Another disadvantage is that MME is only compatible with IBM compatible systems as it is specifically designed to work with the Windows OS. [3]
Direct X
Direct X, namely DirectX 8.1 is a windows supported driver that enhances the multimedia capabilities of a computer. The advantages of DirectX are that it “DirectX provides access to the capabilities of your display and audio cards, which enables programs to provide realistic three-dimensional (3-D) graphics and immersive music and audio effects. DirectX is a set of low-level Application Programming Interfaces (APIs) that provides Windows programs with high-performance hardware-accelerated multimedia support; DirectX enables the program to easily determine the hardware capabilities of your computer, and then sets the program parameters to match. This allows multimedia software programs to run on any Windows-based computer with DirectX compatible hardware and drivers and ensures that the multimedia programs take full advantage of high-performance hardware”. [2]
The disadvantages of DirectX are that it does not support all video modes as all 256 colours aren’t available for direct 3D also, Direct X uses the drivers that come with the video card thus, according to the limitations of the driver, the effectiveness of the output will be compromised. Conflicts with the hardware rendering are due to contributors ranging from D3D not being installed or an older version being present, no 3D accelerator chip present on the video card and the fact that Windows NT only works with Direct X 3.0 or lower whilst Windows XP runs Direct X 8.1. Another disadvantage is that DirectX is only compatible with IBM compatible systems as it is specifically designed to work with the Windows OS. In summation, DirectX is a low latency driver that often experiences difficulties when used as a video driver application. [2] [3] [4]
ASIO
ASIO is an abbreviation for Audio Stream Input/ Output Architecture. It was developed by Steinberg as the software engine for fundamental access to their audio hardware that is Cubase VST; today ASIO is being employed in growing numbers of hardware and software systems that allow the user to implement audio using computers. The fact that ASIO is currently spreading is advantageous as its popularity expresses its effectiveness as a driver to the point where computer manufactures and operating system vendors target the "Multimedia" market and have implemented audio playback and recording capabilities specifically for it. ASIO addressed all areas of pro-audio recording and allows for flexibility when using sample rates, but depths, synchronisation between different media for example audio, MIDI and video. Resultantly, the user is complemented with low latency, high performance, easy to set-up and control recording solution. ASIO currently exists for PC (Windows) and Macintosh systems proving to be yet another advantage, and it allows for one or more soundcards with multiple input and output ports conforming to specifications. On the disadvantage side, ASIO only caters to the user that is in the need of a professional user sound card and call for proprietary expensive hardware based systems making cost a factor, other disadvantages include no support for DX/DXi which is a major issue for live musicians, no scene manager, no rack view, rack editing or rack setup another major issue for live performers and finally there is no scene manager. [3] [5]
WDM
WDM is an abbreviation for Windows Driver Model, which is a driver technology that was developed by Microsoft to combat the ineffectiveness/ latency issues of the latter MME driver. WDM is a low latency driver which is compatible with the most recent Windows Operating Systems such as Windows 98, 2000, Me, and XP. WDM works by channelling some of the work of a device driver into portions of the programming code that are integrated into the operating system which cuts down the latency period, a current advantage. This sharing of channels allows for more processes to be performed in a shorter time period, yet another advantage of this driver type. The WDM device driver is generally more streamlined with less code and works at greater efficiency than most other drivers. Disadvantages of WDM are that it only compatible with IBM compatible systems as it is specifically designed to work with the Windows OS, also, the ‘channelling’ would only be effective in cutting down latency times if the processor and hard drive of the computer is optimised for maximum performance. [3]
‘WDM is also the Abbreviation for Wavelength Division Multiplexing. A technology for transmitting multiple signals at the same time over a single optical fibre. The signals travel within colour bands, with one colour band for each signal” [3]
How may latency be reduced with ASIO/WDM drivers?
ASIO and WDM drivers though considered being low latency drivers, can be improved in terms of reducing latency. Latency may be reduced in these drivers by implementing options that would but back processing time of commands. For example, the reliance of drivers that comes with the soundcard. Basic soundcard drivers sometime come with certain limitations in code and design that often compromise the processing speed leading to high latency thus, ASIO/ WDM should try to develop a driver that would override the driver that comes with the soundcard creating one driver for all sound related operations which would cut back on processing time. The WDM system of channelling should also be further developed, also, further streamlining can be delved into which would mean the use of less code and produce greater efficiency. [3] [5]
Name the primary differences between 'consumer' and 'professional' soundcards.
The primary defences between consumer and professional sound cards resound around differences in processing speed namely latency, price, capabilities and most importantly the quality of sound produced. Consumer soundcards are those that usually come with a computer and are for normal listening use, professional sound cards are usually sought out by audio producing professionals and to some extent gaming enthusiasts and home users who are generally looking for a better ‘sound’. Professional soundcards are more expensive than consumer soundcards and incorporate surround sound, low latency with high fidelity inputs with up to 64 bit processing. If a consumer soundcard is used for recording audio, noisy digital audio, graininess and even hiss may occur due to the characteristics of the cards DAC or ADC. However, there are problems associated with High Definition soundcards such as distortion, pops, clicks and weird noises, all of which can be rectified with an efficient input/ output controller. [1] [3] [5]
Define the following hard drive features/specifications and explain their usefulness in a DAW:
DAW refers to a Digital Audio Workstation, such as Roland’s VS-2480.
Cache
Cache memory is a relatively small memory, which is located close to the calculation circuits of the processor. This memory is a form of RAM [read only memory] which is fast enough to keep up with bus speeds, cache is essential as it houses data that has been currently used with the precedent that data that is recently used will be needed again in the near future. Cache memory can be essential in DAW as it can house recently edited clips that were placed on the ‘clip board’ as it would not take long to retrieve the information thus increasing the options available to DAW users. [3]
Speed in RPM
RPM refers to revolutions per minute and defines the number of times per minute a computer’s hard drive would make complete revolutions. A faster rotational speed is associated with faster data retrieval. A high RPM would be beneficial in DAW as it would allow for fast data retrieval which would enhance the user’s experience. [3]
ATA Type
Why have many people tended not to use AMD processors in DAWs? Is this down to the processor or the relevant motherboard chipsets?
[7]
AMD abbreviates for Advanced Micro Devices, people tend not to use AMD processors in DAWs as
How may an external 'breakout' box be connected to the host PC? Name 3 different ways and describe the benefits and drawbacks of each protocol.
An external breakout box can be connected to a PC via the USB slot using a USB cable, directly into the CD Rom drive or through an audio interface. The benefits of the connection via the USB and audio interface is that it allows for flexibility in terms of how many devices can be attached to the system at any one time, whilst the box inserted via the CD Rom drive can only utilise its manufactured outlets, whilst for example a USB slot can hold up to 127 devices. Drawbacks are such that the boxes that are not directly connected to the machine have a higher latency than the ones that are directly inserted. [8]
What is the importance of cluster size for PC based recordings?
Clusters are the smallest units of storage addressable that is, read or to be written on a device. The size of clusters may vary; the most frequent being sizes of 256 or 512 bytes, but this can vary widely from system to system. Cluster size is relevant to PC based recordings as these recordings are stored on clusters, because of the size of the recordings it is not uncommon to have a file scattered among different locations on the hard disk, that is one file split up into many clusters. Thus, for instance if a cluster goes bad, a significant part of the file will not be accessible, making clusters of vital importance to PC based recordings. [1] [3]
Define the Von Neumann model of PC architecture.
The Von Neumann model of computer architecture centres on the distinction between a machine that performs a task that it is programmed to do and a machine that does a particular job. Today’s computer models are all based on the Von Neumann architecture, which basically sees the computer as a programmable machine that is capable of performing the tasks that it is requested using software that is stored in the computers memory as a guide as to how the process is to be achieved.
Describe each of the following terms and their differences in function:
Point-to-Point connection
Point to point connection refers to a method or wiring or connecting electronic components such as microphones, amplifiers, preamps or any piece of equipment that is directly connected more namely soldered into a tube pin or a solder lug jack. Nowadays, printed circuit boards have replaced all the soldering. Thus, point-to-point connections refer to devices that connected directly to the circuit board without the use of an interface. [3][6]
Bus
The term ‘bus’ in audio technology describes the point in a circuit where many signals are brought together. The term Ground Bus refers to the place where all of the individual ground paths of a device are tied together. The types of buses found in audio production are for example: Auxiliary Busses and Mix Busses. Auxiliary busses are where the feed form channels are brought together and routed to a monitor or an external processor whilst Mix Busses are where multimedia channels are combined together or blended. In summation, the greater the number of busses that a processor has, the more flexible the routing capabilities. [1][3]
Network
A network refers to a multi-computer system as opposed to a single computer bus type system. In a network, multiple access is allowed to all computers within the network, all at the same time. Networks utilise full duplex/ two-way communication between all equipment and computers on the existing network. [1]
In a system with a PCI soundcard, is it more desirable to have the graphics card on the AGP or PCI bus?
In a system with a PCI soundcard, it is more desirable to have the graphics card on the AGP than on the PCI bus. It has larger bandwidth of 266 MBps as opposed to that of the PCI slot, which is 133 MBps. The AGP or Accelerated Graphics Port is dedicated to the process of video applications. It allows for consistent management of memory in its design and “allows scattered data in the system memory to be read in rapid bursts, thereby reducing the overall cost of creating high-end graphics subsystems by using existing system memory.” [3] It greatly speeds up graphics display and texture rendering with noticeable results in the virtual reality and 3D rendering displays whilst conforming to Intel bus specifications. Rather than using the PCI clot for graphics data, the AGP allows for dedicated point-to-point, this channel allows the graphic controller to have direct access to the main memory. [1][3]
Name 2 examples of an optical storage format, and their respective capacities.
Two examples of an optical storage format would be the CD-R disc and the DVD videodisc. The CD-R disc is a read only CD that cannot be rewritten, A normal CD player can read a CD-R that the burning software specified as an Audio CD when the disc was created its capacity ranges from 80 minutes with a 700 MB capacity. Whilst the storage capacity of a DVD videodisc holds as much as 10 times the capacity of a normal CD, it is capable of storing full-length movies in modern day surround sound. The standard DVD holds 4.7 gigs and 133 minutes for MPEG-2 compressed video and audio. [1] [9]
Explain the importance of each of the following factors in a DAW, and what each factor contributes to a DAW;
Speed and flexibility are the most important assets of a Digital Audio Workstation [DAW]. Thus, processor speed, the amount of RAM and Hard Drive Space, all of which contribute to the speed of an operating system are essential to DAW. The amount of RAM namely cache memory is vital to DAW as it provides the system with the much-needed capacity to access recently used data, such as clips copied onto the clipboard. Hard Drive Space is essential to DAW as the size of a hard drive is directly proportional to the capacity of workload that the DAW can achieve, when drive space is limited, applications begin to run slower and in severe cases files will not be able to be saved as due to the lack of space. Processor speed also contributes to the effectiveness of DAW, the higher the clock speed of the processor; the faster DAW can execute instructions. [9]
Explain the following file systems, their associated OSs' and the capabilities of each File System:
FAT
FAT abbreviates for the File Allocation Table, which is a special, file that is located on the disk. It contains information pertaining to the size of the file, and in which clusters the file in its totality can be found. FAT can also keep track of bad clusters and prevent them from being accessed. Drivers have to access FAT to know where the files can be found and to know where in the drive partition to store new information. Associated Operating Systems for FAT [called this because the programs were for the better use of a word ‘bloated’ with two sets of code, one for each environment] are Older Mac programs capable of running in older non Power PC environments such as 68000 series processors as well as newer PPC computers (600 and G series processors) and older versions of the Windows OS.
FAT-32
FAT-32 is a specific type of File Allocation Table [FAT], which has been designed to expand to the demands of the capacity, and capability of the hard drives used in the Windows Operating System environment. FAT has superseded and replaced the previous FAT-16 format previously used, it is a quick fix to the problem that arose of computers shipping out with hard drives with capacities over 2 GB by, allowing much larger partitions instead of splitting hard drives into multiple partitions of under 2GB a piece.
NTFS
NTFS is an abbreviation for the New Technology File System and is associated with the Windows NT operating system. The NTFS allows for information that would have been previously stored in a FAT governing table including other data to be stored in the clusters themselves allowing for more flexibility in terms of where files are stored on a disk is concerned.
[3]
What is a 'partition' on a hard drive?
The partition of a hard drive refers to one or more of the parts in which the drive is divided. A drive can be partitioned so that its capabilities can be used for different kinds of data or even possibly for various hardware platforms. The operating system recognises these partitions and associates them with individual drives, if a drive is partitioned to work with more than one device, each device may be only able to see its own partition, and not the entire drive itself, the exception to this resounds if the software allows it to recognise other file formats. Partitioning allows for data to be categorically stored into smaller spaces which results in faster search results. [3]
What are the advantages of keeping audio on a separate partition/drive to program files?
The advantages of keeping audio on a separate partition or drive to program files are faster search results as data is categorically stored into smaller spaces, the fact that the operating system would associate the audio partition with all associated audio and not the entire drive itself [unless the software allows for other formats to be recognised] cuts down on data location/ retrieval times, also, having a separate drive for audio ensures that the space will be efficiently used for only audio and precious resources won’t be wasted on other formats which could be stored elsewhere.
How does a virtual/soft sampler such as HAlion utilise the host computers resources?
A virtual / soft sampler such as HAlion utilises the host computers resources by seamlessly integrating the processor, partitions, GUI and RAM into the program itself. HAlion incorporates intuitive GUI, which utilises memory to allow the user to recall frequently used settings for envelopes, modulations and FX. Also it allows many views to be opened up in separate windows. Effect sends can be sent to HAlion’s internal FX section or it can be sent to the VST mixer to share plug-in resources between the host [computer] and HAlion a keen example of integration. The RAMSave™, feature incorporated in HAlion keeps check of RAM resources needed by sample instruments this leads to low RAM usage which in tern allows for faster project load and save times. The intuitive sound categories system lets you group related sounds, making it easy to find them quickly, this grouping, utilises the use of File Allocation which is yet another example of integration between HAlion and the host computer. [10]
How many minutes of stereo CD-quality digital audio can be stored in a 1 Gigabyte hard disk partition, approximately?
Approximately ** minutes of CD-quality digital audio can be stored in a 1 Gigabyte hard disk partition.
For a hard disk of 20 Gigabytes capacity or more, what is the most likely backup device, other than another hard disk?
An external zip drive can be the most likely backup device for a hard disk of 20 Gigabytes or more.
Describe four different areas of application in widespread use and give an example of a popular piece of software in each area.
Four areas of application in widespread use are
Describe the main advantages of Firewire compared to SCSI
Firewire refers to a bi-directional interface allowing a single cable to carry MIDI, digital audio or any other presiding signals in both directions it allows for a large quantity single-bus connection (up to 63 computers and other devices). The SCSI [Small Computer Systems Interface] allows many devices (typically up to seven) to connect to one interface card and from there to the motherboard. An advantage can already be deduced as Firewire allows for the attachment of 9 times more devices than SCSI.
The most advanced in the SCSI chain of evolution is the SCSI III interface. In SCSI III the data paths have been expanded, to 68 lines and a high density 68 pin SUB-D style of connector has been incorporated. This interface provides for fast data transfers and is used exclusively for SCSI fixed disks. Firewire is a subset of the SCSI standard and conforms to SCSI standards as well, one major advantage of Firewire over SCSI. Firewire allows for high-speed data exchange, the emergence of Firew | | | |
