Path: utzoo!utdoe!generic!pnet91!taob
From: taob@pnet91.cts.com (Brian Tao)
Newsgroups: comp.sys.apple2
Subject: Re: RamFast Write-Through Cache?
Message-ID: <623@generic.UUCP>
Date: 18 Apr 91 18:45:02 GMT
Sender: root@generic.UUCP
Organization: People-Net [pnet91], Etobicoke, ON
Lines: 22

From asslk@acad2.alaska.edu (Kingry Shane L):

> 1)  The RamFAST/SCSI will write to the disk if it doesn't recieve any
>     data to read from the computer for awhie.  e.g., you send the card
>     a 20K file, and continue with your work.  It writes it when it wants
>     to
> 2)  THe RamFAST will write to the computer when its RAM is full (256K).
>
> My guess is that it uses both.  Either way - it is really worth the money!

    I would much rather have the option of configuring the RAMFast with a
write-through cache.  The Quantum HD I'm using is very fast, so there won't be
much of a delay anyway.  My original beef has to do with the speed of the
writing, however.  If the RAMFast does wait for the 256K to fill up before
writing it out, it takes an awfully long time (relatively speaking) for it to
fill up.  I suspect that perhaps DMA only works in ONE direction: from RAMFast
to GS memory.  It looks like the GS has to do all the data transfer from RAM
back to the SCSI buffer, which is why it can't do high-speed writes to the
drive.  Too bad.

Brian T. Tao   *B-) |  t569taob@bluffs.scar.utoronto.ca  | "Though this be
U of Metro Toronto  |               - or -               |  madness, yet there
Scarberia, ON       |        taob@pnet91.cts.com         |  is method in 't."