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From: jbn@glacier.UUCP
Newsgroups: comp.sys.ibm.pc,comp.graphics
Subject: Re: AutoCad -- How much memory overhead for a block?
Message-ID: <15076@glacier.STANFORD.EDU>
Date: Wed, 28-Jan-87 15:08:07 EST
Article-I.D.: glacier.15076
Posted: Wed Jan 28 15:08:07 1987
Date-Received: Fri, 30-Jan-87 04:09:01 EST
References: <1710@k.cc.purdue.edu>
Reply-To: jbn@glacier.UUCP (John B. Nagle)
Organization: Stanford University
Lines: 30
Keywords: AutoCad, Graphics
Xref: watmath comp.sys.ibm.pc:1231 comp.graphics:216

In article <1710@k.cc.purdue.edu> ag0@k.cc.purdue.edu (Colin Jenkins) writes:
>
>
>...load it into AutoCad representing each pixel as a block.
       A block is a large entity.  This is a very expensive representation.
Try using LINE entities for runs of dark pixels, which produces a sort of
raster scan effect at high magnifications but at the right level of zoom
will reproduce the raster quite nicely.

>
>	If the problem is not AutoCad block sizes, it may be in the hardware.
>The PC tends to be a bit brain damaged and does not operate properly at 10MHz
>speed.  In fact, AutoCad blows up with a "parity error" if it is run at 
>anything higher than 6MHz.
>
      Let's put it this way.  If you undertake to "speed up" a computer,
you are going into the electronic engineering business.  You should know
what you are doing.  A good understanding of such concepts as "operating
margins", "MTBF", "derating", "semiconductor part selection", "temperature
ranges" and "burn-in testing" is essential.  The absolutely essential tools
for someone trying to speed up a computer are a really good set of diagnostic
programs and the facilities to run the machine at a controlled, elevated
temperature for an extended period of time.  Just changing the crystal and
observing that the machine still boots is NOT enough.  Sometimes you have
a faster machine.  More often you now have a machine which makes errors.

      Incidentally, you can get in touch with Autodesk directly on
CompuServ; use "GO ADESK".  

					John Nagle