Re: DMA or not DMA...

[spec@vax2.concordia.ca (Mitchell Spector)]

In article nathan@visi.com (Nathan Mates) writes...

>In article <5kvjei$218i@uni.library.ucla.edu>,
> <pubpc1@library.ucla.edu> wrote:
>>Thus, 500MB is a safe bet because it gives room to grow.  On the
>>otherhand, because the drive does not use DMA, it is a good match
>>for future 8MB RAM expansion.
>
>   8MB is also overrated. One memory-trashing bug, and you've most
>likely toasted your Ramdisk. [And that happens way too often in a
>system without protected memory]. If you want to add lots of
>sounds/fonts/inits/das/etc, you invite lots more bugs, and it takes
>much longer to read them in, magnified by your 30% non-DMA slowdown.
>I've never yet run out of memory on my 4.25MB DMA-happy GS,
>despite running lots of big programs at once, 800K swatdisks, etc.

    I agree, 8 MB is overrated and overkill on the IIgs. Sure it
may be very affordable these days considering 30-pin 1 MB SIMMs
(especially slow 150 ns rated ones) are barely a few dollars. Yet
just to boast big numbers, you have to give up DMA and in some
cases, even deal with compatibility bugs (recall the ROM 3 bug
with RAM Disks and 8 MB). I've still yet to hear of a _single_
application that requires even 5 MB to run, let alone 8 MB.

    My system has 5.125 MB, and even with several extensions loaded
(icons fill the first row at boot) the Finder still reports a little
over 3.7 MB of free memory available. The only time I've ever run
out of memory is trying to load huge stereo digitized sound recordings
I've done with my Audio Animator (e.g. 3-4 MB files!). Of course these
days I rather just record lengthy audio on my PC using 16-bit @ 44 kHz
and then compress it as an MP3 audio file (not only CD quality, but
the same file space gives me several minutes, not seconds ;)

>   Those of you with HS SCSI cards, I'd invite a few benchmarks of
>those with and without DMA (and also with/without any acceleration).
>Boot times are a good real-world measurement, as that's something
>you'll be sitting through a lot of on the GS.

    I still like to boast my boot time of about 4-5 seconds (with
a shift-boot) using the combination of a _DMA_ RamFAST, 11ms SCSI
drive and a 15/64 Zip GS. Or something close to 15 seconds when
loading with all my extensions, which certainly beats the time it
takes my Windows 95 to reboot. ;-)

Mitchell Spector
spec@vax2.concordia.ca