Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!erast1
From: erast1@unix.cis.pitt.edu (Evan R Aussenberg)
Newsgroups: comp.unix.sysv386
Subject: Re: VPix & Dos partition (Was: Simple database software for sysV?)
Message-ID: <88612@unix.cis.pitt.edu>
Date: 7 Feb 91 04:28:57 GMT
References: <6332@spdcc.SPDCC.COM> <1991Feb03.210343.18244@chinet.chi.il.us> <87004@unix.cis.pitt.edu> <1991Feb07.011850.19550@chinet.chi.il.us>
Reply-To: erast1@unix.cis.pitt.edu (Evan R Aussenberg)
Organization: University of Pittsburgh, CIS
Lines: 45

In article <1991Feb07.011850.19550@chinet.chi.il.us> les@chinet.chi.il.us
(Leslie Mikesell) writes:

|[I say]:
| >writing [ with VPix & ISC ] to our Micropolis 320meg scsi is
| >noticably slower than if I access the DOS partition via native DOS...

| >For your reference, the computer is an Intel model 302, 25mhz, 8meg.

|On mine, there is only a slight difference, but I'm running a Conner
|IDE drive which has on-board buffering.  Perhaps you are close to
|missing the interleave on the disk and the overhead of VP/ix is
|enough to miss and require another disk revolution.

|Les Mikesell
|les@chinet.chi.il.us

The Micropolis we have is a voice coil hd with on-board cache as
well.  The interleave of the whole drive is 1:1 because our adaptec
scsi board supports it.  It may well be that the drive is too fast
at 1:1 for VPix.  I don't think you can change the interleave of 
a partition?

The slowdown is typically in the writing.  Reading the DOS partition
under VPix is at least as fast as naitive DOS.

On a semi-related note.  The adaptec 154xB scsi board we have supports
synchronous data transfers to/from its peripherals.  The Mircropolis
drive has a jumper which puts it in "synchronous mode" if available
(that's the best I gather from the docs).  Is there any way to know
for sure that the two are talking synchronously?

Also, how high has anyone set the transfer rate on the adaptec board.
From memory, I think I put the shunt on the 6.x transfer rate.
(It goes to 10ish I think).

Thankyou for all the replies, here and email.  For those interested,
my email replies have concurred with the public posts.


Evan
-- 
Evan Ron Aussenberg
erast1@unix.cis.pitt.edu
IN%"erast1@pittunix"