Author Topic: installing sound cards in windows 95 (1996 article)  (Read 1893 times)

Offline chrisNova777

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installing sound cards in windows 95 (1996 article)
« on: December 14, 2014, 04:35:01 PM »
http://www.soundonsound.com/sos/1996_articles/dec96/installingsoundcards.html

Quote
Despite major advances in PC technology, the platform still has some stumbling blocks that trip up most people sooner or later. Installing and setting up soundcards, floppy and hard disk controllers, SCSI controller cards, MIDI interfaces, modems and graphics cards in a machine with a typical maximum of six or seven slots is bad enough, but juggling the resources needed to get these devices working properly, such as IRQs and DMA channels (see the 'Jargon Buster' box elsewhere in this article for explanations of these and other terms), is something that may at times defeat even the most experienced PC guru. There are solutions to most problems, but often, in the absence of clear and detailed technical information, it is easier to negotiate a refund on a piece of hardware than battle on to resolve a problem.

The arrival of Windows 95 was heralded as the 'cure-all' for hardware installation problems, by incorporating so-called 'plug and play' facilities into the PC's software and BIOS which could then automatically interrogate plug and play-compatible cards for information related to installation and resources required. Since Windows would know the facilities already used by previously-installed plug and play hardware, it was supposedly a simple matter for it to allocate appropriate resources from the pool of remaining choices. That was the theory! In practice, legacy (ie. pre-Windows 95) devices still often have to be installed by hand, and whilst it is a laudable effort to streamline things, plug and play will only be totally effective in several years time, when the majority of hardware devices conform to its requirements. In the interim, some devices are recognised, and some are not. However, with the multiplicity of devices attached to the modern PC, the pool of resources is rapidly drying up, and additional approaches need to be tried which make the most of the ever-dwindling set of IRQs and DMAs.

Traditionally, there have been two routes to try if you need further information when a resource drought threatens. Unfortunately, the first of these, namely the manual supplied with Windows 95, has proved a non-starter, as it is of pamphlet proportions, and is more a token gesture than a serious attempt at a handbook. The second approach is to search out one of the many excellent reference books on Windows 95, but these can be very expensive (going up to over £50), and many require a course in the gym before you can lift them! What is needed is something in the middle ground, collecting together all the essential things that a MIDI musician using Windows 95 will need to hand when setting up a new soundcard or MIDI interface. Here, then, is the Sound On Sound guide to installing add-on cards.


BASE ADDRESS CHOICES

Every piece of hardware will need to use a set of I/O addresses, so that information can be written to and read from it. Manufacturers of cards will provide a selection of possible Base Addresses (the starting or first byte used) in order that each device gets a unique set of addresses. Various default addresses are used for specific functions. For instance, MIDI interfaces often use 330h (hexadecimal), and if you have two or more interfaces in your machine, at least one will need to be changed. If two devices end up with the same or overlapping addresses, then commands sent to either of them will be gibberish to the other, and the computer will probably have a minor fit. It is always safest to note down which of the small provided selection you end up choosing for future reference .
IRQ CHOICES

There are a total of 16 available IRQs, numbered from 0 to 15 inclusive. Many are already allocated for use by other computer functions such as scanning the keyboard and mouse, controlling the flow of data to and from floppy and hard disks, and updating various timers and clocks used by the system. Six IRQs are commonly available to choose from when installing hardware such as soundcards and SCSI controller cards: 5, 7, 9,10,11, and 12. You may see references to IRQ 5 or 7 being allocated to the parallel ports (normally used by a printer, but also by the new breed of external MIDI interface such as the MOTU PC-Flyer or Pocket Express, reviewed on page 205 in this issue). By default, Windows 95 does not allocate any IRQ to the parallel port, since it is rare for any printer to need an interrupt, so these remain in our pool of choices. IRQ 15 is sometimes used if you have two IDE disk drives installed, but, again, is normally an option.

IRQ 2 can be confusing. In early PCs, only eight interrupts existed, and to extend this to 16 in later machines, IRQ 2 was used by internal hardware, but mapped onto IRQ 9. Choosing IRQ 2 is therefore not a problem, but it will actually be IRQ 9 that carries out the work. This is why you may see references to IRQ 2/9 in many places; they are effectively the same thing. Isn't technology wonderful?
DMA CHOICES

DMA is used in conjunction with interrupts to move around chunks of data such as sound automatically, without tying up the PC's processor. Most soundcards use DMA, as well as many SCSI controller cards and certain enhanced IDE disk controllers. There are eight channels of DMA available, numbered from 0 to 7 inclusive (0 to 4 are 8-bit, and 5 to 7 are 16-bit channels). As you might expect, the 16-bit channels can move data faster, and so give better performance with those devices that can use them. Unfortunately, since there are only three of them, it can be hard to work out the best way to allocate DMA resources. If you use a SCSI drive for audio, and have a controller card which uses a DMA channel (such as the Adaptec 1542), it is best to put the controller card on DMA 7 and the soundcard on DMA 5 or 6. DAL CardD Plus users should use DMA 5 for playback and DMA 6 for record. This is because DMA channels are prioritised, and if you give the highest priority (number 5 for 16-bit channels) to the soundcard, clicks and pops should not occur because the SCSI controller is hogging the majority of the finite DMA time. Most PCI SCSI controller cards do not use DMA channels, and also provide better drive performance than those using DMA, so this becomes a prime consideration when choosing a controller card. Some soundcards, such as some of the Turtle Beach range (Monterey, Tahiti and Multisound) do not use DMA channels to shift audio data about, but a faster proprietary architecture called Hurricane, which is claimed to be up to eight times faster than DMA. This allows them to run more tracks of audio mixed down to stereo than the common-or-garden soundcard, although they are comparatively more expensive.