🚀 go-pugleaf

Chaim Manaster (manaster@yu1.yu.edu) wrote:
: >> If SmartDrive is unsure its
: >>a good idea to install in anyway.
: >
: >I disagree. Trying it on my SCSI drive, the start-up time of windows
: >doubles with double buffering installed. And this also reflects on all
: 
: Fine, but if you then discover that you needed double buffering,
: what consequences have you  suffered.
: 
: In other words, if your system needs double buffering and you did
: not invoke it what disasters befall your system. Are these
: consequences gradual, or do they occur in one fell swoop. Where do
: you look to find these consequences that may or may not occur.
: 
: What is it about SCSI and ESDI drives (Ihave one of each) that
: incur the wrath of no double buffering?
: 

Where the problem comes in, is with DMA bus master type cards. These need
an area of low memory for their DMA buffers. An ASPI manager (at least
Adaptec's) provides this, and hooks INT13 to make sure all plays well.

What will happen most likely, is that if you don't have an ASPI manager,
and you load your disk cache into high memory, then invoking Windows will
usually corrupt your disk, and do so very quickly. This is because Windows
uses upper memory regions, and will conflict with the DMA buffer.

SmartDrv in double buffer mode will avoid this by using 2 buffers, but
performance suffers. Loading a good cache, like hyperdisk in low memory,
also avoids the problem. If you want the cache loaded high, and run
Windows, then load the ASPI manager and all will be OK.

Russ Poffenberger               DOMAIN: poffen@sj.ate.slb.com
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