Gilderfluke&Co old MACs 8 bit Digital Audio System - Manual (Page 92)

- Hardware Requirements -
To use the DAS-100, you will need an IBM AT class machine or compatible running a 80286 (or
better) processor at a speed of at least 12 MHz. The screen needs to support EGA or better. The DAS-100
to IBM interface is a 'short' card which can be mounted in any 8 or 16 bit slot available. For color
displays in the DUMP MENU, you will need an EGA or better screen.
The hard disk and its controller needs to be fast enough to support a 1 to 1 interleave and 28
millisecond access times. This normally means that the disk controller must have a 16 bit interface to the
IBM bus and the hard disk drive will need to be of the 'RLL', 'EISA' or 'SCSI' varieties. If the disk is too slow,
you may not be able to sample at all, or will only be able to sample monophonic signals. Storing audio
samples eats up a lot of hard disk space. When taking a stereo sample at 15 KHz bandwidth, it will require
4 MBytes per minute just to store the original sample. The program can then generate several overlays
having to do with this file as you perform evaluations and optimization, and then the EPROM image files
you will eventually burn can take up as much room as the original sample file (although these can be
redirected to another disk or saved just a few at a time).
Since you will eventually need to erase the samples you have already taken to open up hard disk
space, a tape backup device is highly recommended to allow you to archive old samples. It is usually
much easier to retrieve an archived sample and burn new EPROMs from it than to have to start from
scratch if you need to make some minor changes in an installation.
The DAS-100 is a memory mapped device. It requires 8 k bytes of address space. This normally starts
at D00000H. It will not work if anything else is located in this memory address area. (Even if your
machine has more than 640 KBytes of memory installed, this extra memory is normally mapped to
addresses above the area we are concerned with.) If there is a conflict with some other device on the
bus, the DAS-100 can be re-addressed anywhere between 000000H and FFFE00H. Check your manuals
for all other equipment and memory on the bus to assure that there will be no conflicts with your existing
hardware. If the DAS-100 needs to be re-addressed, the jumpers located on the board can be moved as
needed. They are marked from A-13 to A-19. Inserting a jumper on a pair of pins sets that address bit
'low'. Removing it sets it 'high'. Contact the factory if this presents a problem for you.
The DAS-100 software doesn't burn EPROMs directly, but instead saves files to disk in the proper
format for later burning into EPROMs using virtually any commercially available EPROM burner. This allows
you to get a simple and inexpensive single chip burner if you will only occasionally be burning chips, or
a fast set burner which can do 8 or 16 chips simultaneously if you will be burning a lot of chips. The
requirements for the EPROM burner are that it is compatible with IBM compatible computers, can take a
binary format input file, and can handle the larger CMOS EPROMs which are used by the Digital Audio
Repeaters. These are 27C512 (64 k x 8), 27C010 (128 k x 8), 27C020 (256 k x 8) 27C040 (512 k x 8),
and 27C080 (1024 k x 8) EPROMs. Note that some manufacturers will shuffle the order of the last three
digits of the part numbers so that a 27C010 may be called a 27C100, etc.. The speed of the EPROMs is
not terribly important for the Digital Audio Repeaters. Any speed at or below 200 nanoseconds will be
plenty fast,. It isn't very likely you will find these larger EPROMs at any speeds slower than 200
nanoseconds. EPROMs used in the Digital Audio Repeaters must be manufactured using CMOS memory
technologies.
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