ben m
Joined: 15 Sep 2002
Posts: 337
Location: UK |
| Week 3 - Computers 2 |
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Lots of questions this week.
Again, aim for concise answers that outline all the points made in the question.
Here they are;
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.
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
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 Sep 20, 2004 2:31 pm |
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Rico1210
Joined: 03 Aug 2004
Posts: 39
Location: Newcastle, UK |
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Hi,
here are my answers to week 3 questions, they are getting harder 
Define the following terms:
Latency
Latency can be defined as the time it takes a packet of data to get from one designated point to another. The time it takes the data to reach the designated point then return to the sender is considered to be the latency. In other words, latency is delay.
Duplex
Duplex is described as the ability to send and receive data at the same time. A telephone conversation is an example of Full-Duplex. An intercom system is an example of Half-Duplex, where only one person may speak at a time.
Buffer
A buffer can be described as a temporary memory location for data in transit from one device to another. It helps the transfer of data between two devices of different speeds, in other words it enables a device to operate without being held up by the other. In programming buffering implies the need to screen data before being moved to its destination.
Define the following Sound Card driver types and their advantages/disadvantages;
MME
MME (multimedia extension) is designed to work with nearly all sound cards but has very high latency, therefore is not favoured by professionals.
Direct X
Direct X was created by Microsoft for creating and managing graphic images and multimedia effects when running applications. Direct X produces lower latency levels than MME but does not have the ability to record.
ASIO
Audio Stream Input/Output is a cross-platform, multi-channel audio transfer protocol that allows software to have access to the multi-channel capabilities of an advanced sound card. The advantages of this are that it allows the host application to access all of the inputs/outputs of the soundcard. The user can then assign these as needed for recording or playback, thus allowing more tracks to be recorded simultaneously other than the standard two channels of a standard sound card.
WDM
Windows Driver Model is a driver developed by Microsoft which offers very low latency because it bypasses the operating system to communicate directly with the hardware. Is only compatible with Windows 98, 2000, ME and XP
How may latency be reduced with ASIO/WDM drivers?
Latency is reduced with ASIO/WDM drivers because they communicate directly with the hardware and also give the user the option of setting their buffer levels. The faster your system, the less read-ahead buffering it will need to keep up with the flow of audio, and the lower the latency will be as a result. The smaller the buffer level, the lower the latency.
Name the primary differences between 'consumer' and 'professional' soundcards.
The primary differences between 'consumer' and 'professional' sound cards are that 'consumer' cards are very basic in that they usually only come with ports for the connection of speakers and a microphone. A 'professional' sound card generally comes with a lot more inputs and outputs, usually via a front mounted interface. These ports include digital input and output, MIDI input and ouput and standard microphone and headphone ports. A 'professional' soundcard is designed to use low-latency drivers liek ASIO, DirectX and WMD.
Define the following hard drive features/specifications and explain their usefulness in a DAW:
Cache
A cache is a temporary storage area for data. For example, when accessing web pages files will be copied to a cache for quick retrieval when re-visiting that site. Therefore any commands frequently used will be accessed immediately.
Speed in RPM
RPM is an abbreviation of revolutions per minute. The more revolutions per minute, the faster data can be accessed.
ATA Type
Advanced Technology Attachment or IDE (integrated drive electronics) are the interface between motherboard and hard disk. There are many types of ATA including ATA-2(or Fast ATA), ATA-3, Ultra ATA, ATA/66, ATA/100 and ATA/133. A faster ATA type will enable files to be accessed quicker.
Why have many people tended not to use AMD processors in DAWs? Is this down to the processor or the relevant motherboard chipsets?
Intel are preferred for use in DAWs as the chipsets tend to be more stable and have no compatibility problems.
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.
via PCI, USB or Firewire
PCI connections are usually used in desktop PC's as there is plenty space for expansion, whereas a laptop does not have extra slots to fit PCI cards. Therefore USB or Firewire have to be used when connecting to a laptop. USB interfaces cannot record more than four simultaneous inputs, so Firewire would be preferred as it does not have the bandwidth limitations of USB. Firewire or USB could also be used with desktop PC's as they are popular for their ease of connection.
What is the importance of cluster size for PC based recordings?
Cluster size is important in PC based recordings as the bigger the cluster, the less clusters used. Therefore less time will be taken when compiling files from clusters.
Define the Von Neumann model of PC architecture.
The Von Neumann model of PC architecture is the theory that a computer's programs and the data it processes do not have to be fed into the computer while it is working, but can be stored in the computers memory to be called upon when required. This concept serves all modern computers and is often referred to as the 'stored-program computer'
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 would be more desirable to have the graphics card on the AGP(Accelerated Graphics Port) bus as it is dedicated to graphics.
Name 2 examples of an optical storage format, and their respective capacities.
An example of an optical storage format would be CD-R (Compact Disc Recordable) which has the capacity to hold up to 800MB of data on one disc. Another example of optical storage is DVD (Digital Versatile Disc) which has the capacity to store approximately 4 gigabytes of data per layer. Some DVD's have the capacity to store 4 layers, which is 16 gigabytes per disc.
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 is important in a DAW as the more RAM, the faster and smoother programs will run. Programs will run simultaneously without latency problems.
Hard Drive Space
Hard drive space is very important in a DAW as this is where you will be storing all samples, recordings etc. Audio files tend to take up a lot of space, so a large hard drive is recommended.
Processor Speed
Much like the amount of RAM, processor speed is important. A fast processor will enable commands to run a lot faster and will improve latency.
Explain the following file systems, their associated OSs' and the capabilities of each File System;
FAT
A File Allocation Table is a table that an operating system maintains on a hard disk that provides a map clusters that a file has been stored in. These clusters will not necessarily be situated next to each other, therefore an entry is created to record the order of clusters and where they are situated. When you read a file the operating system reassembles the file from the clusters and shows it as one file. Using Windows 95 FAT length is limited to 16bit which limits hard disk size to 512MB, assuming maximum cluster size of 8,192. Hard drives of up to 2 gigabytes can be supported by using up to four partitions each with a seperate FAT.
FAT32
As above but has a FAT length of 32bit. Hard disks of up to two terabytes (2 trillion bytes or 2000gigabytes) could be supported by FAT32. FAT32 are used with following operating systems: Windows 95 (OSR2), Windows 98 and Windows ME.
NTFS
New Technology File System is the system used by Windows NT to store and retrieve files from a hard disk. It is the equivalent of FAT on Windows 95 but ofers better performance, extendability and security. Information about a files cluster map is actually recorded with each cluster instead of in a FAT. NTFS uses a B-tree directory scheme to keep track of files. It supports very large file sizes, up to 16 billion bytes in size.
How does a virtual/soft sampler such as Halion utilise the host computers resources?
Virtual/soft samplers like halion access data from the hard drive. They store a portion of this data in the RAM to reduce latency.
How many minutes of stereo CD-quality digital audio can be stored in a 1 Gigabyte hard disk partition, approximately?
Approximately 100 minutes of stereo CD-quality digital audio can be stored in a 1 Gigabyte hard disk partition. This is because the sampling rate for high-fidelity audio is 44,100 samples per second, 2 bytes are needed per sample to achieve a good signal to noise ratio. 44,100 x 2 = 88,200 x 2 channels for stereo = 176,400 x 60 seconds per minute = 10 and a half megabytes of data per minute. 1 Gigabyte is approx 1000mb
For a hard disk of 20 Gigabytes capacity or more, what is the most likely backup device, other than another hard disk?
The most likely backup device other than an external USB hard disk would be recordable DVD's.
Describe four different areas of application in widespread use and give an example of a popular piece of software in each area.
Four different applications in widespread use would be: Sequencer software (Cubase), Sampling software (Halion), Virtual Studio (Reason), Mastering Software (T-Racks)
Describe the main advantages of Firewire compared to SCSI
The main advantages if Firewire compared to SCSI are, Firewire is faster and allows more devices to be connected at any one time. Firewire devices are hot-swappable.
In relation to computer software;
What is a driver?
A driver is a program that interacts with a particular piece of hardware or software, that contains special knowledge of the hardware/software interface.
What is an extension?
An extension is an addition to the filename or a suffix. It represents the type of file, usually in the form of three letters ie. bmp (bitmap), exe (executable). This suffix enables a program to recognize if the file is in a format that is compatible.
When changing sampling frequency, what happens to the latency?
If the sample frequency is increased the latency decreases. Therefore if the sampling frequency is decreased, latency will increase.
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 may be attached to a SCSI bus is 15 not including the host device on an Ultra320 SCSI. On standard SCSI the maximum is 7.
If it is necessary to reconnect or reconfigure the devices on a SCSI bus what precaution should be taken?
When reconnecting or reconfiguring SCSI devices, the PC should be shutdown before any devices are reconnected as SCSI devices are not hot-swappable.
How many terminators would there normally be on a SCSI bus? Where would they be situated?
The normal amount of terminators on a SCSI bus is two. They are situated at either end of the SCSI chain.
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?
If the devices in a SCSI chain are not working correctly, the first things to check would be the cables. Followed by the terminators. The device at the end of the chain must have termination turned on, whereas the first device or any devices in the middle of the chain will have termination turned off. This is controlled by a small jumper switch on the back panel.
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?
What is lacking from Macintosh version 9.0.4 and lower operating systems is the ability to multitask. Therefore running more than one application at a time would cause problems.
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 disks would be expected to allow more tracks to be played simultaneously as they are faster and can hold more data.
Which is usually thought to offer the most reliable long-term storage, removable magnetic hard disk cartridge or magneto-optical disk?
A magneto-optical disk offers more reliable long-term storage as it has magnetic field protection.
Compared to digital tape, what is the principal disadvantage of disks for long-term storage?
The principal disadvantage of disks for long-term storage is that they are more perishable than digital tape. This is because they have mechanical parts that will wear with time.
Explain the advantages of newer 64-bit processors.
The advantages of 64-bit processors are that they provide higher performance than 32-bit processors as they can handle twice as many bits of information per clock cycle. Also, they are backwards compatible with older applications and operating systems and can detect whether an application or operating system is 16-bit, 32-bit, or 64-bit.
Explain why currently 64 bit processors can not be used to their full potential.
64-bit processors are not currently being used to their potential as there are not many pieces of software that are compatible with them. This includes Microsoft Windows.
Detail the CPUs used in Apple Macs in recent times.
The CPU used most recently in Macs is the G series (G3, G4 etc)
Had problems finding out about Mac processors, can anyone point me in the right direction  |
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Mon Sep 27, 2004 3:05 pm |
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ben m
Joined: 15 Sep 2002
Posts: 337
Location: UK |
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Hey Rico,
good work.
a few things to look at further though.
Firstly latency.
Your description of latency is essentially correct but how could you apply it to MT?
For instance, what effect does latency have on Virtual Instruments and also on monitoring via software?
Amount of RAM.
Again, what you have written is correct but there are other relevant answers. For instance, a software sampler needs a lot of RAM - why?
How does a virtual/soft sampler such as Halion utilise the host computers resources?
To be more specific, some soft samplers may store the first part of a sample in RAM meaning that if you play a certain sample the RAm will hold the first few ms/s and by the time this is exhausted the sample will have been located and streamed from disc.
For a hard disk of 20 Gigabytes capacity or more, what is the most likely backup device, other than another hard disk?
Any other devices? The main example is not as common now but is still used.
When changing sampling frequency, what happens to the latency?
Again your answer is correct but you could add more detail - what would happen if you doubled the sampling freq.?
What is lacking from the Macintosh's operating system?
Correct in outline but examine 'pre-emptive' multitasking.
Detail the CPUs used in Apple Macs in recent times.
There are a couple of specific examples here. One starting point would be motorola.
Good work Rico. |
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Tue Sep 28, 2004 8:08 pm |
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ben m
Joined: 15 Sep 2002
Posts: 337
Location: UK |
Rico,
also to add;
ATA Type
What about SATA? |
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Tue Sep 28, 2004 8:10 pm |
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ben m
Joined: 15 Sep 2002
Posts: 337
Location: UK |
| Missing Answers |
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All of you (except Rico)
you need to get this section nailed ASAP
Missing this section will have implications when the exam comes round so please make this a priority.
Any problems then please post here.
thanks,
ben m |
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Tue Sep 28, 2004 8:12 pm |
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aik
Joined: 03 Jun 2004
Posts: 10
Location: Glasgow |
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Oh bhoy, that was a struggle. I must admit that my English in terms of technical language isn’t highly developed.
But at least here are my answers.
Define the following terms:
Latency
Latency in audio terms is the delay from a note being played from an instrument till it actually can be heard.
Duplex
Duplex is the possibility to simultaneously transmit a signal in two directions, like recording and play back at the same time.
Buffer
A buffer in terms of computers is an area to temporary store data, usually in RAM
Define the following Sound Card driver types and their advantages/disadvantages;
MME – Multi Media Extension is a general driver for all soundcards. It has a high latency though and provides only stereo input/output, which doesn’t make it very useful for audio work.
Direct X – is an Application Program Interface for Windows OS, which is mainly designed for graphic use. It is faster then MME but doesn’t allow duplex communication and provides only stereo input/output.
ASIO – Audio stream input/output is developed by Steinberg for multi channel functionality. You can see all the available inputs and outputs and record more tracks simultaneously. It has a low latency and is designed for professional audio work.
WDM – Windows driver model is the newest driver developed by Windows and so far only compatible with the newer Windows OS’s. It has en even lower latency as the ASIO driver because it bypasses the operating system.
How may latency be reduced with ASIO/WDM drivers?
By reducing the number and the size of buffers.
Name the primary differences between 'consumer' and 'professional' soundcards.
The professional soundcard is obviously designed for professional audio work. It provides you with more inputs and outputs, using XLR and Ľ”connections whereas the consumer soundcard uses mini jack for one input and one output. The pro card has a lower latency and allows higher sample rates.
Define the following hard drive features/specifications and explain their usefulness in a DAW:
Cache - cache is minor amount of memory to temporary store data for immediate access.
Speed in RPM – Speed in Rotation per minute defines the speed of rotation of the hard disk. As faster it rotates as faster you’ll get access to your stored data, which is very useful for audio work where you want to record and playback several tracks at the same time.
ATA Type – Advanced Technology Attachment defines the speed of transferring data between the hard disk and the operating system. As faster the speed as more data can be transferred, as lower the latency and therefore as more suitable for professional audio work.
Why have many people tended not to use AMD processors in DAW’s? Is this down to the processor or the relevant motherboard chipsets?
There is a latency issue with VIA chipset motherboard
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.
Via Firewire, USB or PCI card. Both Firewire and USB have a high data transfer rate (if using USB 2.0) and are suitable for portable systems. USB is furthermore quite cheep and compatible with all platforms and you would hardly find a computer without USB port. USB 1.1 may cause latency problems when transferring multiple tracks. The PCI card is inside the computer and would connect to the breakout box via ribbon cable. It has a high speed data transfer rate.
What is the importance of cluster size for PC based recordings?
Cluster is a unit of storage on the hard disk and the size is set by the operating system. If the clusters were to big a lot of storage space would be wasted, as the amount of bytes in a cluster not used by a stored file would not be used at all. If the cluster size were too small, the quite large audio files would be stored in several clusters, which would slow down the data transfer.
Define the Von Neumann model of PC architecture.
Von Neumann invented the basic structure of the modern computer as is a memory, containing instructions and data, a processing unit to perform arithmetic and logical operations and a control unit for the interpretation of instructions
In a system with a PCI soundcard, is it more desirable to have the graphics card on the AGP or PCI bus?
It is preferable to have the graphics on the AGP – Accelerated Graphics Port as this is designed for that purpose.
Name 2 examples of an optical storage format, and their respective capacities.
CD-R which has a capacity of about 800 Mb and DVD-R which has a capacity of up to 16 GB using four layers
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 determines the amount of processing that can be done at a time. As more amount of RAM as smoother will the system run.
Hard Drive Space – audio data require a lot of storage memory, therefore, for a DAW, as much hard drive space as possible is recommended.
Processor Speed – You would need a fast processor for all the information to process adequately and provide a smooth performance.
Explain the following file systems, their associated OSs' and the capabilities of each File System;
FAT – File Allocation Table is used by the operating system to locate files on a disk. FAT16 is designed for small disks and simple folder structures. The associated OS is the older version of Windows 95 and DOS.
FAT32 – is a newer version of FAT16. It increases the number of bits used to address the clusters and reduces the size of each cluster. It can support larger disks and has a better storage efficiency. The associated OS’s are Windows 95 OSR2 and Windows 98.
NTFS - (New Technology File System) is originally designed for Windows NT and is the most advanced file system for PC’s. The NTFS partition can be almost of any size. It has good security, better crash protection and can handle large amounts of data. The associated OS’s are Windows NT, Windows 2000 and Windows XP.
How does a virtual/soft sampler such as Halion utilise the host computers resources?
Halion utilizes the hard disk whenever it needs to access the samples stored there. It also utilizes RAM where the first part of each sample would be stored to avoid latency. A smooth performance of a virtual/soft sampler requires a fast hard disk and a large amount of RAM.
How many minutes of stereo CD-quality digital audio can be stored in a 1 Gigabyte hard disk partition, approximately?
Approximately 100 minutes:
frequency rate x bits per sample/8 = bytes per second.
Bytes per second x 60 = mono file size per minute in MB
2 x mono file size per minute in MB = 1 stereo file size per minute in megabytes.
44.1 x 16 / 8 = 88.2
88.2 x 6. = 5292 (5.292MB)
2 x 5.292 = 10.584 MB per minute.
1 GB (1000MB) / 10.584 = 96.15 Minutes.
For a hard disk of 20 Gigabytes capacity or more, what is the most likely backup device, other than another hard disk?
CD-R or DVD-R
Describe four different areas of application in widespread use and give an example of a popular piece of software in each area.
Sound editing – Wavelab
Virtual sampler – Halion
Video editing – Final Cut Pro
Sequencer - Nuendo
Describe the main advantages of Firewire compared to SCSI
Firewire is faster
Firewire is hot-swappable
Firewire provides power to the device it is attaching.
More devices can be connected via Firewire and it has thinner cables
In relation to computer software;
What is a driver?
A driver is a software that comes with each device and works as a translator between the device, the operating system and the software that might be using the device.
What is an extension?
An extension are the three letters, which follows the dot after the file name to indicate for a program if it would be compatible.
When changing sampling frequency, what happens to the latency?
Sampling frequency and latency are reverse proportionate to each other. Increases the sampling frequency decreases latency and opposite.
Excluding the host device, what is the maximum number of devices that may be attached to a SCSI bus?
A narrow SCSI bus can support up to 7 different devices and a wide SCSI bus up to 15.
If it is necessary to reconnect or reconfigure the devices on a SCSI bus what precaution should be taken?
As SCSI is not hot-swappable the computer should be shut down and all devices turned off.
How many terminators would there normally be on a SCSI bus? Where would they be situated?
Every SCSI bus has two terminators, one at each end of the 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?
I would check if the terminators are installed correctly, check if there isn’t an ID conflict and everything is connected and installed correctly.
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?
The MacOS’s before MacOS X were lacking pre-emptive multitasking, which allows the computer to switch between several running applications.
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?
As the magnetic hard disk is faster then the magneto optical disk, I would expect it to be the better choice to playback many tracks simultaneously.
Which is usually thought to offer the most reliable long-term storage, removable magnetic hard disk cartridge or magneto-optical disk?
A magneto-optical disk is the best choice for long-term storage. It is quite temperature stable and has a longer shelf life then a magnetic hard disk.
Compared to digital tape, what is the principal disadvantage of disks for long-term storage?
The principal disadvantage of disks is that they are containing mechanical and moving parts, which makes them more sensitive as tapes. There could also occur compatibility problems as technology is developing fast.
Explain the advantages of newer 64-bit processors.
64-bit processors allow operating systems and applications to process more data in the same amount of time and access a huge amount of memory.
Explain why currently 64 bit processors can not be used to their full potential.
Not many applications are at the moment compatible to this new architecture.
Detail the CPUs used in Apple Macs in recent times.
After the G3 and G4 processors the newest CPU’s for an Apple Mac are single and dual Power PC G5 processors at 1.8GHz, 2GHz and 2.5GHz. The dual processors divide up tasks between two CPU’s, which makes the computer even faster, but not double as fast. |
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Wed Sep 29, 2004 7:23 pm |
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seanm
Joined: 06 Sep 2004
Posts: 20
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hello Ben
sorry for delay here's my answers
Define the following terms:
Latency
Latency in DAW’s is simply the time it takes a DAW to move audio from one place to another. Each time a signal is altered, the DAW needs time to carry out calculations and since the signal is transferred in “chunks” rather than a continuous stream, this introduces a time delay equivalent to the size of the chunks. Latency is the time delay between triggering a signal through a soundcard and actually hearing it. Latency also affects the general responsiveness of applications.
Duplex
Duplex refers to a sound cards ability to accept sound in and out at the same time
Buffer
Buffers are small areas of RAM which store data, they are designed to prevent a break in the data stream whilst the processor is performing other tasks. Buffer memory stores this data in the order it is required. Each time the processor returns it tops up the buffer with more data.
Define the following Sound Card driver types and their advantages/disadvantages;
MME
MME was the first windows sound card driver and was introduced with windows 3.1, it is characterised as having high latency, but can work well with some standalone soft synths.
Direct X
One of the components of Direct X is Direct Sound. Direct sound drivers generally have lower latency than MME drivers and perform better with soft synths and audio playback. If however you are running them with windows 98/ME they don’t normally have recording options.
ASIO
Introduced by Steinberg Audio Stream Input Output (ASIO) drivers bypass much of the windows operating system and as a result they have lower latency than both MME and Direct Sound drivers.
WDM
WDM was first introduced with windows 98 and works even better with windows xp. It has better performance with USB and Firewire resulting in much lower latency than MME. Like ASIO drivers WDM drivers bypass much of the windows OS and it’s associated slow down, communicating directly with the soundcard.
How may latency be reduced with ASIO/WDM drivers?
ASIO and WDM drivers communicate directly with the soundcard and allow the user to set different buffer sizes. Both features can be used to reduce latency.
Name the primary differences between 'consumer' and 'professional' soundcards.
Many consumer soundcards do not provide full duplex sound.
Rather than phono inputs professional soundcards have balanced (XLR) 1/4in inputs and optical inputs.
Professional soundcards often have “phantom power” and Hi-Z capabilities.
Professional soundcards have the ability to record and playback higher sample rates (44.1khz and 96khz)
Professional soundcards with ASIO drivers can support the recording of multiply tracks.
Define the following hard drive features/specifications and explain their usefulness in a DAW:
Cache
The cache is an area of memory where files are temporarily stored whilst waiting to be written to disk (Saved). When a program saves date to the hard drive it is not written immediately but stored in cache memory until windows decides it has the appropriate time and resources to finally write the data to disk. This can interrupt the flow of audio signals, causing pops and clicks etc.
Speed in RPM
The speed at which a hard drive spins and therefore can be accessed is expressed in RPM or revolutions per minute. As audio files are relatively large this speed is crucial due to the real time nature of audio recording and playback.
ATA Type
ATA stands for AT Attachment an interface developed by IBM for it’s AT Computer. It is the original name for IDE which stands for Integrated Drive Electronics. ATA’s or newer SATA’s (Serial AT Attachment) are the motherboards connection for a hard drive. Different ATA and SATA models operate at different speeds, again affecting the performance of a DAW. The faster the ATA or SATA the faster audio can play and record in real time.
Why have many people tended not to use AMD processors in DAW's? Is this down to the processor or the relevant motherboard chipsets?
AMD Athlon based PC’s required a different motherboard to Intel Pentium based ones. Some early Athlon chipsets were incompatible with some soundcards. Such problems have now almost disappeared.
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.
PCI slot via a Serial Port. PCI breakout boxes for sound cards require their own exclusive PCI slot and are not “hot swappable”. There is a limit to the number of PCI slots within a PC. There is a new generation of PCI-X which will provide more bandwidth and be hot swappable.
USB2 or USB high speed is a high speed serial standard (transmitting one bit of data after the next in one long stream) with a maximum bandwidth of around 480Mbits a second. USB2 supports hot swapping of devices and is backwards compatible with USB1 devices.
Firewire or IEEE-1394 is a high speed serial standard with a maximum bandwidth of around 400Mbits a second. It has a reputation for causing fewer “hiccups” during data transfer which is a must for DAW’s. Firewire supports hot swapping of devices and has peer to peer topology (you can plug firewire devices directly into each other without a PC). Firewire operates with a maximum cable length of around five metres.
What is the importance of cluster size for PC based recordings?
Audio files are generally large taking up more sectors of a hard drive. Sectors are organised into clusters, which are the smallest “allocatable” unit of disk storage. Processors when retrieving audio data have no choice but to read whole clusters into RAM. If the Clusters are relatively large they will contain more sectors and therefore more audio data. Therefore larger cluster sizes allow data to be read more quickly because more sectors of the drive are read at one time.
Define the Von Neumann model of PC architecture.
Named after John von Neumann who created an early computer which stored instructions as binary values (creating the stored programme concept) and executed instructions sequentially. “von Neumann architecture” refers to the sequential nature of modern computers based on his model.
In a system with a PCI soundcard, is it more desirable to have the graphics card on the AGP or PCI bus?
Advanced Graphic port or AGP is a dedicated high speed interface between PC memory and a graphics card and monitor. Before its development graphics cards were fitted in PCI slots and could cause audio clicks and pops. These “glitches” were caused when the graphics card didn’t release the PCI buss for other duties when requested, preventing audio data from reaching the sound card.
Name 2 examples of an optical storage format, and their respective capacities.
CD-R capacity around 750megabytes.
DVD capacity 4gigabytes.
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 (Random Access Memory) has a number of implications for a DAW.
Track Count, the more RAM the larger the number of tracks a DAW can run at once. More RAM will increase the track count and the sample rates which can be used in real-time playback and record.
Soft Samplers (eg Halion, Kontact) the bigger the RAM the easier to use these. Soft Samplers are very RAM hungry with references to all sample starts and the first part of samples being held in RAM whilst the programme is running.
VST instruments (e.g. Moog Modular, Absynthe) again the bigger the RAM the more VST's it can handle. All such programmes need to be held in RAM whilst the programme is running.
Software Plug-ins (e.g. Waves, Grm tools) the bigger the RAM the more plug-ins it can run at once.
Hard Drive Space
Audio files are large, and file sizes increase at higher sampling rates. The larger the hard disk the more can be stored.
Processor Speed
The faster the processor the more it can do in real time. For a DAW this is very important, the faster the processor the more software plug-ins and soft synths, samplers can be used.
Explain the following file systems, their associated OSG’s' and the capabilities of each File System;
FAT
The FAT or file allocation table is used by windows to keep track of which clusters are assigned to each file (a cluster being the smallest allocatable part of a hard disk. This is the bedrock of data retrieval. FAT is a relatively old system which only worked with hard drives up to 2 gigabytes. FAT 16 as it is often called stored information very inefficiently it could only store information in 32 bit clusters, making every file at least 32 bit in size.
FAT32
FAT 32 was an improvement in that it had a minimum cluster size of 4k bits saving a lot of wasted space and could is recommended by microsoft to work with drives up to 32 gigabytes. Windows 95/98/ME and XP
NTFS
NTFS or New Technology File System was introduced with Windows NT and also works with XP. NTFS cluster sizes can be altered to as low as 512 bits avoiding wasted space almost completely. It can work with drives of enormous capacity up to 2 terabyte’s in size. NTFS is also much less susceptible to date corruption and is self repairing.
How does a virtual/soft sampler such as Halion utilise the host computers resources?
Halion, loads samples onto the hard drive and loads a portion (the start of the sample) into RAM (software buffers). When a sample is selected the start plays from RAM while the rest is streamed in real time from the drive. Some soft samples load the whole or the sample into RAM.
How many minutes of stereo CD-quality digital audio can be stored in a 1 Gigabyte hard disk partition, approximately?
CD quality is 44.1khz sampling rate in 16bit stereo. Approx 2 megabyte per minute therefore approximately 100 minutes.
For a hard disk of 20 Gigabytes capacity or more, what is the most likely backup device, other than another hard disk?
A large capacity high speed tape drive.
Describe four different areas of application in widespread use and give an example of a popular piece of software in each area.
Software sequencer Nuendo
Audio Editor Soundforge
Software Sampler Kontact
Software Synthesiser Absynthe
Describe the main advantages of Firewire compared to SCSI
Firewire is hot Swappable
Auto configuration (plug and play)
Firewire can support up to 63 devices,
Small connectors and thin flexible cabling.
In relation to computer software;
What is a driver?
A driver is a small piece of software required by all hardware enabling the hardware to function within the host OS. Drivers are frequently updated in order to maximise hardware performance.
What is an extension?
A file extension is a three letter suffix attached to a file telling the OS what type of file it is, and usually what software it will open in/with.
When changing sampling frequency, what happens to the latency?
Latency is calculated by dividing the buffer size by the sampling rate. For instance a sample buffer of 1,024 at 44.1 Hz yields a latency of approx 23ms. At a higher sampling rate of 96khz the latency is approx half this length.
Excluding the host device, what is the maximum number of devices that may be attached to a SCSI bus?
7 or 15 depending on the specification. For example SCSI-1 devices allow 7 excluding the host. SCSI-2 Wide, SCSI-2 Fast/Wide and SCSI-3 both SPI-1 and SPI-3 both allow 15 devices excluding the host.
If it is necessary to reconnect or reconfigure the devices on a SCSI bus what precaution should be taken?
SCSI devices are not hot swappable, therefore before reconnecting or reconfiguring devices it is necessary to power down the system, carrying out these changes before re-booting.
How many terminators would there normally be on a SCSI bus? Where would they be situated?
Two terminators are required, one for each end of the SCSI bus. If there is only one series of devices (internal or external), then the SCSI controller is one terminator and the last device in the series is the other. If there are both internal an external, then the last device on each series must be terminated.
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?
First check all cables are correctly seated, then check that terminators are accurately placed and the switches are on or off depending on the relative position of the devices in the chain. If a fault is detected power down, make the appropriate changes and re-boot.
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?
Prior to OS X Macintoshes operating system did not include Pre-emptive multitasking. This allows for the running of applications in the background (eg word processing) without significant impact on the main application running.
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. Magneto optical hard disk recorders are usually designed for location recording.
Which is usually thought to offer the most reliable long-term storage, removable magnetic hard disk cartridge or magneto-optical disk?
With the size, price and portability of high speed cross platform external hard drives (eg maxtor and Lacie). Any concerns about reliability might be overcome by using two. But it is thought by some that magneto-optical disks offer the best option, as they have no moving parts to wear out.
Compared to digital tape, what is the principal disadvantage of disks for long-term storage?
Disks contain moving parts which can perish and/or break.
Explain the advantages of newer 64-bit processors.
64 bit processors can support up to eight CPU’s in one machine. Some are able to support more RAM.
Explain why currently 64 bit processors can not be used to their full potential.
Currently most software applications do not support 64 bit processing, including windows.
Detail the CPUs used in Apple Macs in recent times.
G5, G4, G3, CPU: PowerPC 750 PowerPC 603ev
sean |
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Fri Oct 01, 2004 4:44 pm |
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