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From: res@cbnewsc.ATT.COM (Rich Strebendt)
Newsgroups: unix-pc.general,comp.sys.att
Subject: Re: Should I buy a 3b1?
Summary: UNIX PC graphics emulation very poor
Keywords: PC graphics on AT&T 7300
Message-ID: <12766@cbnewsc.ATT.COM>
Date: 11 Jan 90 22:53:59 GMT
References: <2421@ttardis.UUCP>
Organization: AT&T Bell Laboratories
Lines: 40

In article <2421@ttardis.UUCP>, rlw@ttardis.UUCP (Ron Wilson) writes:
| In article <10678@rama.UUCP>, lvw@rama.UUCP (Lyndon VanWagner) writes:
| |I'm considering purchasing a used unix-pc (3b1, 7300) as a home machine.
| |However, I would like to check on its MSDOS (if any) compatibility, when
| |the DOS board is installed.  Can anyone give me their experiences with
| |this?  Is the screen compatible with some IBM PC graphics board?
| 
| I am reading from the AT&T "UNIX-PC Reference Manual."  In the section
| describing the "DOS-73 Coprocessor" card, page 1.2, "General Description,"
| the manual claims that the DOS coprocessor emulates a Hercules MONOCHROME
| graphics card.  
| ... However, I don't have a DOS coprocessor card, so I can't tell you how
| well it really works.

I have a DOS-73 board, so I can comment from experience.  For
character graphics the emulation is quite acceptable.  I run programs
like Harvard Total Project Manager (Version 1.0) on it and the PERT
charts and Gantt charts look just fine.  For bit level graphics the
DOS board is absurd.  For example, if I try to run TETRIS on it, the
display looks like a TV set with a horrible horizontal sync problem.
Each line of the display is offset from its predecessor by a large
amount.  Any program that tries to do Hercules bit-level graphics
simply trashes the display.  This appears to be because the PC and the
UNIX PC screens have different numbers of pixels per row(?).

Add to this problem the problem that the memory is terribly undersized
for modern applications.  For example, HTPM versions beyond 1.0 are
too big to fit into the undersized DOS board's memory.  While it is
claimed that there is 512K of memory, only about 400K of it is
available for applications to use.

So, if you are looking to do fancy graphic applications using the
DOS-73 board, you may be disappointed.  However, if character level
graphics are sufficient for your needs, the board will probably do
fine as long as your application will fit.  Despite these limitations,
I personally have found the DOS-73 board to do a good job for the
kinds of things I want to do with it.

					Rich Strebendt
					...!att!ihlpb!res