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From: c55-hc@ucbbuddy.BERKELEY.EDU (Brent Chapman)
Newsgroups: net.micro.pc,net.lang.pascal
Subject: Turbo Pascal 3.00B BlockRead/BlockWrite bug
Message-ID: <11044@ucbvax.BERKELEY.EDU>
Date: Wed, 20-Nov-85 23:00:05 EST
Article-I.D.: ucbvax.11044
Posted: Wed Nov 20 23:00:05 1985
Date-Received: Sat, 23-Nov-85 00:43:38 EST
References: <3424@brl-tgr.ARPA> <11043@ucbvax.BERKELEY.EDU>
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Reply-To: chapman@ucbugs.UUCP (Brent Chapman)
Organization: University of California, Berkeley
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Xref: watmath net.micro.pc:5934 net.lang.pascal:381

If people already know of this, I apologize.  

There is a bug in MS-DOS Turbo Pascal,
version 3.00B, in the 'blockread' and/or 'blockwrite' procedures.
Version 3.01A is available from Borland, which fixes these bugs.
Also dealing with the blockread/blockwrite procedure, while not 
technically a bug, there is an undocumented limitation to these
procedures.  You cannot read/write more that 64K bytes (512 blocks) 
with a single blockread/blockwrite command.  This is due to the IBM
addressing structure (each segment addresses a max of 64K bytes).
If you try to access >=512 blocks, you end up dealing with (X mod 512).

Hope this helps some people!

Brent Chapman
ucbvax!ucbugs!chapman		chapman@ucbugs.berkeley.ARPA
ucbvax!ucbamber!chapman		chapman@ucbamber.berkeley.ARPA
ucbvax!ucbbuddy!c55-hc		c55-hc@ucbbuddy.berkeley.ARPA

Opinions expressed herein are strictly my own (but are available for
use by others for a reasonable fee).