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Monster Media 1996 #15
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Monster Media Number 15 (Monster Media)(July 1996).ISO
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sound
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it203a.zip
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DRIVERS.DOC
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1996-06-04
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Notes about the sound drivers
1) Gravis UltraSound
This file actually contains two drivers in one file. The first is
accessed just by using IT (with no command line parameters, or with
/s4 for Gravis UltraSound). This is equivalent to the original
internal driver that came with previous versions of Impulse Tracker.
The second driver is specified by providing the correct IRQ for the
GF1 chip. (The second-to-last number of your ULTRASND environment
variable). This is an IRQ driven routine, which means that it'll
work in the background of Windows '95. But note that the timing for
this is NOT as accurate as the timing in the first driver. There is
also a possibility that multitasking OSs can sometimes (although
rarely) cause some settings to the GUS to be missed (which will cause
a note to play unexpectedly). This can be fixed just by restarting
playback. There is NO check for the correctness of the IRQ provided.
The Gravis UltraSound *CANNOT* cope with 16-bit samples greater than
256k-bytes. This is equivalent to 128k-samples. Also, 16-bit samples
cannot cross 256k boundaries on the GUS, meaning that the amount of
memory you have on the card may decrease by more than you expect when
you load a 16-bit sample.
You cannot choose the mixing rate for the GUS - the mixing rate is
dependent on the number of channels you initialise the program with
(using /Lxx)
2) InterWave - Hardware mixing ONLY. You *NEED* to have RAM onboard to use
this.
This file actually contains two drivers in one file. The first is
accessed just by using IT (with no command line parameters, or with
/s6 for AMD Interwave IC). This is similar to the original internal
GUS driver that came with previous versions of Impulse Tracker.
The second driver is specified by providing the correct IRQ for the
Interwave chip. (The second-to-last number of your INTERWAVE
environment variable). This is an IRQ driven routine, which means
that it'll work in the background of Windows '95. But note that the
timing for this is NOT as accurate as the timing in the first
driver. There is also a possibility that multitasking OSs can sometimes
(although rarely) cause some settings to the GUS to be missed (which
will cause a note to play unexpectedly). This can be fixed just by
restarting playback. There is NO check for the correctness of the IRQ
provided.
If you are running a multitasking OS, you MAY need to run IWINIT before
running Impulse Tracker to have more memory detected.
The Interwave driver contains handlers for two different memory modes
on the Interwave - the more memory efficient mode is where the amount
of ram is directly compatible with the interwave, the second is where
the DRAM configuration is NOT directly compatible with the interwave
and the driver has to handle the RAM slightly more explicitly, which
causes the loss of memory-usage efficiency.
Here are the modes directly compatible with the interwave:
Bank 0 Bank 1 Bank 2 Bank 3 Total
256Kb 0 0 0 256Kb
256Kb 256Kb 0 0 512Kb
256Kb 256Kb 256Kb 256Kb 1MB
256Kb 1MB 0 0 1.25MB
256Kb 1MB 1MB 1MB 3.25MB
256Kb 256Kb 1MB 0 1.5MB
256Kb 256Kb 1MB 1MB 2.5MB
1MB 0 0 0 1MB
1MB 1MB 0 0 2MB
1MB 1MB 1MB 1MB 4MB
4MB 0 0 0 4MB
* 4MB 4MB 0 0 8MB
* 4MB 4MB 4MB 4MB 16MB
* These modes cannot be handled by the first driver, so are actually
handled in the second mode.
The mixing rate for the Interwave driver is fixed at 44100Hz
(CD quality)
Bug warning: If the sound does NOT play properly, you may need to
run IWINIT before running Impulse Tracker