Newsgroups: comp.sys.amiga
Path: utzoo!utgpu!jarvis.csri.toronto.edu!csri.toronto.edu!drz
From: drz@csri.toronto.edu (Jerry Zarycky)
Subject: Re: Hard Drive & Chip Contention
Message-ID: <8903232240.AA05683@yorkville.csri.toronto.edu>
Organization: University of Toronto, CSRI
References: <16061@cup.portal.com>
Date: Thu, 23 Mar 89 17:40:39 EST

In article <16061@cup.portal.com> Bruce_Eric_Bowers@cup.portal.com writes:
>
>  
>I've read the discussion about the A2090A with interest, as I am planning
>to buy a A2500 or A2000HD soon. What are the symptoms of the contention
>problem? Is it just slower disk access time, slower disk *and* slower
>screen updates, glitchy screen :-(, hung machine :-( :-( ?
> 

The symptoms are VERY SLOW disk access time.  I've only had these
problems with static screens (not that animation would help :-)).

>What types of screen displays cause how much of a problem? (IE, does

I believe that any 640x200 or 640x400 display with 4 bit-planes
is guaranteed to cause a problem.

>the problem get better and worse depending on the display mode, or is
>it no problem at all until its a big problem? (Is it every a *big*
>problem?))
> 

There is no problem until there is a problem, and EVERY problem
is a BIG problem.  When one of these screens comes up, a picture
that would take a few (< 5) seconds to load, now takes MINUTES to load,
with the hard disk controller LED on SOLID, with the drive making a
steady noise. (To be fair, I'm not sure how many minutes it takes to
load, since I abort it before it has a chance to finish).

>I would consider an A2000 with a third party hardcard, but those package
>prices for the 2000HD and 2500 make it awfully tempting (especially the
>2500).

Flipping to a "normal" screen via the screen to back/to front gadgets
will cause the transfer to complete quickly, but this is a pain to
have to do all the time, and could be EXTREMELY frustrating if the
screen you are on has no such gadgets.
All in all, when you are demoing a program which uses this type of
screen (Professional Page, I think) to some potential Amigaphile
and he sees the contortions you have to go through to load a file,
he may be sufficiently turned off.  ("How come you have to flip
to another screen to load/save a file????", he asks).
Apparently, this problem can be minimized if you have real FAST
RAM (i.e. non-CHIP RAM), but the standard computer won't come
that way.

> 
>As always, thanks to everyone for any information offered!  

You're welcome.
   ^
   |
   spelled correctly!



Jerry Zarycky

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