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Path: utzoo!utgpu!water!watmath!clyde!cbosgd!cwruecmp!neoucom!wtm
From: wtm@neoucom.UUCP
Newsgroups: comp.sys.att,comp.sys.ibm.pc
Subject: Re: Wanted: GRAPHICS.COM for AT&T 6300 hires
Message-ID: <653@neoucom.UUCP>
Date: Mon, 10-Aug-87 11:42:39 EDT
Article-I.D.: neoucom.653
Posted: Mon Aug 10 11:42:39 1987
Date-Received: Wed, 12-Aug-87 04:19:22 EDT
References: <806@sask.UUCP> <2614@ur-tut.UUCP>
Organization: Northeastern Ohio Universities College of Medicine
Lines: 29
Keywords: AT&T 6300, graphics, MS-DOS
Xref: utgpu comp.sys.att:786 comp.sys.ibm.pc:5774
Summary: Spaeking of graphics bugs...


There are some minor bugs in the CGA screen mode (320 * 200, four
colors) in AT&T's GW-BASIC (tm Microslush).  Sometimes, red objects
will be offset a few pixels to the right of where they should be.
The bug (um... feature?) exists up thgouh version 3.1 release 1.01
of the O/S.  I've comfirmed that this problem exists with several
copies of GW-BASIC fresh out of the box on a number of 6300s.  I've
found that the red-shift bug does not exist in Xerox's release of
GW-BASIC for their version of the Ollivetti M-24 AKA Xerox 606x or
AT&T 6300.

Here's another one for the record.  IBM's "MOTOR" statement for
controlling the motor relay on the original PeeCee is an illegal
statement in AT&T's GW-BASIC.  I guess that makes sense since there
isn't a casette port on the 6300.  Some other incarnations of
GW-BASIC simply ignore the MOTOR statement as if it were a REM.  In
this case, I'd say that the AT&T implementation is "more correct"
since it is more likely to catch bugs due to ports of old programs.

Lastly, AT&T's GW-BASIC will trap a floating divide error
correctly, thus allowing you to handle divide-by-zeros within your
program.  IBM basic simply terminates the user program when error
number 11 happens.  I'm glad to see that IBM's ways have been
righted here as it makes writing plotting programs much easier
since it is possible to detect exceptional values without crashing
the user program!

  --Bill
(wtm@neoucom.UUCP)