Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!oliveb!sun!wolf!dhelrod
From: dhelrod%wolf@Sun.COM (David Elrod)
Newsgroups: comp.graphics
Subject: Re: 4014 stuff
Message-ID: <51704@sun.uucp>
Date: 3 May 88 03:46:56 GMT
References: <206300001@prism> <2007@rtech.UUCP> <508@wsccs.UUCP>
Sender: news@sun.uucp
Lines: 44
Summary: Another OPINION on the 4014 stuff.

I had some experiences at Ohio State Universities 'ADML' lab
(Mechanical Engineering Department.) that might shed some light
on some of the confusion here.

The 4014 had two display modes:
1) Normally, anything written to the display was "stored" there until
   the whole screen was cleared.
2) "Write-through" mode that allowed users to temporarily write to the
   screen.

The cursors (text and crosshair) both used write-through mode.  This
was normally very limited in its usefulness.

It was possible to connect a high speed interface from a host (at
OSU it was a VAX 11/750) which would devote 110% of its time (or so
it seemed) to refreshing the display of the 4014 (using write-through
mode).  As I recall, the department had software (possibly from SDRC)
that would animate mechanical linkages using this interface.

Tektronix made an expansion board that had some memory, a 6800
microprocessor and 4 ROM sockets (of which 3 were empty). ADML's
system manager dis-assembled the code in ROM and extended it so that a
display list could be down loaded into the terminal across a 9600 baud
RS232 line.  The resulting product (after months of hacking) was the
ability to animate about 2K vectors per second (my memory is fuzzy on
the 2K number, but that seems about right). Doug's display list was
ring of frames that the 6800 stepped through.  You could get 100
vectors at 20 frames per second which looked pretty nice!  This
compared reasonably with the "high speed interface" version, and 6
students could all work simultaneously!

He talked with Tektronix and eventually sold his modification to
several big companies (GE, some big-3 auto company, SDRC, ...).  His
price varied from about $50 for the first ones to several hundred each
when he found out the demand.  The big companies liked it because they
owned hundred's of 4014's and could postpone the inevitable upgrade to
raster.

This kind of trick (and there may be others that have done something
similar) could account for all of us having such different ideas about
what the 4014 could do.

dhelrod@sun

(I wish I could think of things like that!)