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From: jb10320@uxa.cso.uiuc.edu (Jawaid Bazyar)
Newsgroups: comp.sys.apple2
Subject: Re: What does a ZIP/TWGS speed up?
Message-ID: <1991Jun29.013304.29029@ux1.cso.uiuc.edu>
Date: 29 Jun 91 01:33:04 GMT
References: <1991Jun28.213429.11556@risky.ecs.umass.edu>
Sender: usenet@ux1.cso.uiuc.edu (News)
Organization: University of Illinois at Urbana
Lines: 27

giovin@risky.ecs.umass.edu (Rocky J Giovinazzo) writes:

>I was wondering... will an accelerator card effect disk access time?
>I'm trying to decide whether to spend the extra $70 on a
>RAMFast SCSI card for a hard drive (as opposed to an Apple SCSI)
>since the RAMFast is apparently faster.  

>I assume that an accelerator might slightly speed up disk accessing
>since disk operations involve a little bit of CPU time (right?).  Is
>this amount of "speed up" on the order of the difference between
>RAMFast and Apple SCSI cards?  Or is the difference between the 
>RAMFast and Apple SCSI much more significant?

   The RAMfast is only significantly faster for Prodos 8 applications- GS/OS
isn't accelerated as much (although it is faster).  With an accelerator,
GS/OS can process the data being read much faster (especially in the case
of loading a program file- programs have to be converted from OMF to 
straight 816 assembly), but the actual transfer of data from controller
to main RAM won't be faster, since both the RAMFast and Apple cards use
DMA.  But again, it makes a significant difference in boot time and the time
it takes to run programs.
   
--
Jawaid Bazyar               |  "Twenty seven faces- with their eyes turned to
Graduated!/Comp Engineering |    the sky. I have got a camera, and an airtight
bazyar@cs.uiuc.edu          |     alibi.."
   Apple II Forever!        |  I need a job... Be privileged to pay me! :-)