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Re: Testing Sirius RAM card at 8MB? (and now SCSI termination?)

Matthew Carpenter wrote:

Mark Frischknecht wrote:


PZ wrote:


The other thing that you can try is to create a 4MB ram disk.  Ram
disks start at the "back" of the ramcard and work forwards, so a 4MB
ramdisk would take up the last 4MB on the card.  Thus, unless you were
writing to the ramdisk itself (or ran a program from the ramdisk), the
Apple Highspeed SCSI would never need to DMA into "non DMA-able" memory
space.

- Paul



Have you tried the memory tester program that comes with Appleworks GS?

/r
Mark Frischknecht



Hi,
I've been doing a few things at once lately... Got a 128k mac and a real mess to clean up that have both been pulling at me... anyway I just turned off DMA and now it was able to boot up and copy the file... it just seems odd that they would put it in the manual as being ok.
Anyway I am going to Tukwilla today so I will be stoping in at REPC <www.repc.com> to buy a bundle of their 50� 1MB SIMMS for spares.... when I get back I'll try the Appleworks GS memmory tester.... I'm also going to fill up a zip file with a bunch of random stuff off my Mac to produce a zip file that's bigger than 8MB, burn it to a disk and attempt to copy it from the CD ROM to the Hard drive and see if it crashes while copying that. 

Also, I have a question about Termination...

presently I have:
Apple HighSpeed SCSI card -> Apple CD 150 -> Passthrough terminator -> 350MB Quantum hard drive in.
The Hard drive doesn't supply termination... the pass through terminator can supply term power, but it says something else is already doing it(I don't know what).My question is, is this a bad setup? What would be a better setup than this? 

Although it is possible that your High Speed SCSI card is modified to
supply termination power, I'm guessing that it isn't.  That would mean
that the Apple CD 150 is supplying term power.

You might (in principle) move your passthrough terminator to the end
of the chain (the unused SCSI connector on the last drive--the Quantum)
to get the termination closer (but not much) to the electrical end of
the chain.  Since we're only talking about the length of SCSI cable
*inside* the Quantum drive (assuming that the terminator is currently
on the Quantum end of the cable connecting the CD 150 and the Quantum),
any improvement in signal quality is likely to be marginal.
I have a 50pin centronics hard drive case I could put the 350MB in (right now its in a case with one of those really condensed connectors) and a bunch of pass through and end 50-pin centronics terminators sitting in a drawer... the CD150 is a 50pin centronics device already. 

Although it might simplify the cabling a bit, this change isn't
necessary.  You already have a properly terminated chain.

-michael

Music synthesis for 8-bit Apple II's!
Home page:  http://members.aol.com/MJMahon/

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