🚀 go-pugleaf

In article <129...@sun.Eng.Sun.COM> linden@sun.UUCP (Peter van der Linden) writes:
>The PDP-8 was a peculiar system.  I first programmed one in 1977,
>and it was obsolete even then.   It has a 12-bit word length,
>leading to an astonishing 4K of memory.   This can be extended by
>bank switching to 12K or even more.

> [..]

On a somewhat related note, the DECMate I (and II and III, I think)
word processors, which DEC brought out in the early 80's, ran on a PDP-8
microprocessor.

The DECMate was also something of a peculiar system.  The DECMate I
consisted of a somewhat modified VT100 terminal, which in addition to
the usual VT100 innards was equipped with a slot for the PDP-8 motherboard.
The VT100 sat atop a compact wheeled box, which contained two to four
RX02 8-inch floppy drives (klunk! klunk!) and a couple of logic boards
to drive them.  The keyboard was supported by a removable metal "shelf"
that mounted to the front of the rolling case.  (The "grabbers" that held
the shelf onto the case were made of what appeared to be cheap pot-metal,
and the ones in use here were constantly breaking.  We finally had our
machine shop whip up a bunch of stainless steel ones for us when we ran
out of spares.)

Not a bad system to use, considering that DEC had more or less cobbled
it together as a quick first entry into the word processor market (although
I think there was an even older version, using a VT52 and a slightly
different disk format, and (I think) called something else), and I think
the price was pretty reasonable for the time.  However, despite the
fact that the monitor was a (full-screen) VT100, all editing occurred on
the bottom line of the screen.  This was a major annoyance to many, who
tended to flock to true full-screen products like WordPerfect when they
became available.

I always wondered what method had been used by DEC to optimize the
handling of all those 8-bit characters using a 12-bit machine, or if
in fact any optimization had been implemented at all.  Does anyone know
how this was handled?  Was 2/3 (the upper 4 bits of each word) of the
DECMate's memory "wasted", or were the characters packed into memory
across word boundaries?  Were the characters written to disk in 8 or
12 bit "bytes"?  It seems like a good use of the upper 4 bits might
have been to indicate things like whether the character was bold,
underlined, etc.  Anyone know?


A curious former DECMate repair-being

...who wonders, too, how many DEC LQP02 (El Kewpie :) printers out there
might today be leading more-or-less productive lives attached to IBM PC's,
if only the stupid things knew how to handle EIA flow control (they used
only XON/XOFF).  Then again, maybe it's the stupid IBM PC, whose standard
printer device is (or was) too dumb to know about XON/XOFF...
-- 

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"Puir Airnie"