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From: wa60@sdcc12.UUCP (paul van de graaf{})
Newsgroups: net.micro.atari8
Subject: 256K Upgrades and Ramdisks
Message-ID: <553@sdcc12.UUCP>
Date: Mon, 17-Mar-86 07:44:54 EST
Article-I.D.: sdcc12.553
Posted: Mon Mar 17 07:44:54 1986
Date-Received: Tue, 25-Mar-86 02:57:50 EST
Organization: U.C. San Diego, Academic Computer Center
Lines: 33

I recently upgraded my 800XL to 256K using a revised version of the Byte
article mod.  The new version pages in memory in 16K chunks, and is pretty
much compatible with XE software.  I'd guess it's similar in design to the
CDY 256KXL upgrade.  It's 8-256K RAM chips, and either 3 or 5 TTL chips de-
pending on which ANTIC chip you have.  I built it for $35.00 and an afternoon
of my time.  If you're interested in this mod, check with your user-group --
mine printed it in their newsletter.  I would have posted it, but I doubted
I could ASCII-fy the scematic.

Anyway, I'm using the patch to DOS 2.5 that was posted to Usenet a while back.
It is supposed to give you two 720 sector ramdisks.  Well... I tried it and
I'm having a few problems.  Sure enough, I have 2 ramdisks, but I'm getting
some errors from DOS when the ramdisks get close to full.  It appears that
somehow files near the end of the disk get corrupted and their file numbers
get changed somehow.  This gets DOS upset, and renders the files unuseable.
My guess is that somehow the wrong memory page gets bank-switched in, or
the ramdisk gets overwritten.  I haven't looked into it too closely.

Has anyone else had this problem?  For a while there I was suspecting the
hardware, but I did some memory tests and could find nothing wrong.
I'll be glad to try and find a patch to DOS 2.5, if I can confirm that it's
a software problem.  To duplicate the problem on your system, copy a disk
with about 700 sectors on it to D8, and then try to copy the files on D8 to
a blank disk.  IE. C(opy) D1:*.*,D8:  then  C(opy) D8:*.*,D1:.

By the way, did anyone try the homebrew Action! run-time library I posted
here a couple of weeks ago?  I expected some kind of response to it, but
nada.  In the past, UCSD has had some problems with postings not getting
out of the local net.  Perhaps it's happened again.  The posting is ~400
lines long, so I hesitate to post it again.  Send me mail in either event,
as I can't be sure this post will get out either!

Paul van de Graaf		sdcsvax!sdcc12!wa60		U. C. San Diego