OctoRAM, High Speed SCSI and Zip GS

[ltchean@iss.nus.sg (Lim Thye Chean)]

Hello, I am heving a little difficulty here.

I am buying a High Speed SCSI card from my friend, to replace my Rev. C card,
but encountered some problem. This is my configuration:

ROM 1 GS, OctoRAM 2MB (256K simms), Zip GS (9MHz/32K), Rev.C SCSI, two
harddisks (40MB Western Digital, 120MB Quantum), and a AI sound card.

The problem starts when I replace my Rev. C with the High Speed SCSI. 
Suddenly, 

1. Some of the inits/DAs gets conflict during boot-up, 
2. Shift-booting gives me a Finder screen with corrupted fonts, 
3. Using 3.5" System 6 to boot, my harddisk is reported corrupted.

Panic, I tried to use ProSel to repair, but it seems that they are beyong
repairable.

So even more panic, I used my Rev. C...

1. Harddisk is workable, all files are there, just that my System 6 is
   corrupted (Finder reports required 300K during bootup, I have never
   encountered this message except after quitting some applications)

2. I reinstalled System 6, everythings work fine.

Thus I tried to switch off the DMA of High Speed SCSI, now it works. 
So, I think it must be the DMA conflicts, but why? The friend I bought the
card from also used OctoRAM, but he does not used a Zip GS. So...

1. Is it because of Zip that cause the problem? 
2. Is it because not all OctoRAM are the same (that is, some OctoRAM is
   DMA-compatible and some are not)?
3. Is it because of some other thing I am not aware of?
4. Can I use RAMFast instead? 


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          Lim Thye Chean: Lim is my surname. My name is Thye Chean.
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