Path: utzoo!censor!hugh
From: hugh@censor.UUCP (Hugh D. Gamble)
Newsgroups: comp.sys.amiga
Subject: Re: Info Recommendations on system
Summary: maxtransfer honesty
Message-ID: <851@censor.UUCP>
Date: 30 Jul 89 23:34:10 GMT
References: <1350@amigash> <419500002@S67.Prime.COM>
Organization: Bell Canada, Business Development, Toronto
Lines: 61

In article <419500002@S67.Prime.COM>, CFW@S67.Prime.COM writes:
... 
> We have 2 of these configurations, except with the 80mb disk (it's a disk,
> not a hardcard - I mounted mine in the left half-height floppy drive slot).
> I was interested in getting the 100mb disk, but GVP said (and still says
> as of 7/21/89) that they are having manufacturing problems with the 100mb
> disk and it is not available.  I have been told by GVP that a 160mb disk
> will be available "by the end of the quarter" - which quarter I don't know.
> 
> Note that the disk uses an AT driver - it is not a SCSI device.
> 
> Seems to work just fine, although I discovered a problem with the max
> transfer rate of the disk's AT driver.  Seems that it wasn't being set
> at all, and this caused problems because the drive loaded data TOO FAST
> for some software (like DPaintIII 3.1) to handle it - it hung the system.
> GVP has a fix for this (they told me this on 7/26/89) and will be shipping
> out new drivers to registered owners with the max transfer rate set to 128K.

Sounds like you're being snowed by "marketspeak".  I'm sure it makes GVP
owners feel better if they think their drive is "too fast" for normal S/W,
but the truth is that maxtransfer is a kludge that Commodore added for
3rd party HD controller vendors who don't know how to write proper driver
S/W.  Specifically, there is a limit on the largest IO transfer that the
controller can handle in a single request.  If a number larger than this is
requested, the proper thing for the driver to do is to break it up into
requests of a suitable size, & everything gets handled transparently to
all higher level S/W.

The fix C= provided for people with controllers with driver S/W that
doesn't do this, is maxtransfer.  It keeps requests bigger than a
specified size from ever getting to the controller (does what the
driver should be doing).

DeluxePaint III is a good test for this flaw, because it has a very large
load module likely to cause this problem to show up.

Controller vendors who had this problem originally, should have fixed
their S/W.  If GVP still hasn't fixed their flawed S/W you should ask them
why not. Setting maxtransfer will patch over the problem, but isn't the
real solution.

[rest of article deleted]
> 
> >    ///  /_\         	Scot L. Harris    !hoptoad!peora!rtmvax!amigash!scot
> >  \XX/  /   \ M I G A   	    		
> >[If you can keep your head when all about you are losing theirs, perhaps
> > you have misunderstood the situation.]
> 
> Christopher Wroten
> Prime Computer Inc.
> 500 Old Connecticut Path
> Framingham, Ma. 01701
> 508-879-2960 x4336 (7:30am-4pm EST)
> Internet: CFW@S67.PRIME.COM


-- 
Hugh D. Gamble (416) 581-4354 (wk), 267-6159 (hm) (Std. Disclaimers)
hugh@censor, kink!hugh@censor
# Jimmi Hendrix isn't dead, I saw him on channel 10.
# (unknown)