[GreenKeys] [External] Kleinschmidt 7302 ?

[dave.g4ugm at gmail.com]

> -----Original Message-----
> From: greenkeys-bounces at mailman.qth.net <greenkeys-
> bounces at mailman.qth.net> On Behalf Of Jones, Douglas W
> Sent: 31 July 2022 03:39
> To: David I. Emery <die at dieconsulting.com>
> Cc: Greenkeys <greenkeys at mailman.qth.net>
> Subject: Re: [GreenKeys] [External] Kleinschmidt 7302 ?
> 
> From: David I. Emery [die at dieconsulting.com] -- Friday, July 29, 2022 5:53
PM
> 
> On Fri, Jul 29, 2022 at 08:47:56PM +0000, Jones, Douglas W wrote:
> >         As someone around computers back then (70s) I'd say in my
> > experience it was considerably more than half of the really seriously
> > high speed high volume LPRs.   These were not table top units... more
> > things the size of a Cooper Mini  ...
> 
> They weren't that big, but I really do like using the Mini as a unit of
volume for
> comparison purposes.  The drum printer that left me (50 years later) with
minor
> hearing loss was about the size of the slant-front desk I'm sitting at
right now.
> That one was from DEC, attached to a PDP-11.
> 
> >         I was aware of IBM chain printing, but actually used and even
> > owned
> medium size Data Products drum printers and one or two larger ones at
work...
> and I'm not particularly aware they ever made chain printers then (or
maybe
> later)
> 

The weirdest drum printer I ever met was attached to a Honeywell H61/60 Mini
Computer.
It did not have a full width drum, to save money it had type wheels, one for
every fourth space.
There was a weird mechanism to move the paper across, so it made weird
noises as it printed.

To reduce smudging it had a mylar template with slot like holes for the
hammers.
It was an obnoxious machine. You had to power the whole computer down to
changes the ribbon which was great except it ran four terminals....
.. we also had a real fun day when it stopped printed on one of the wheels.
The engineer changed everything he could think of. Still not print.
Turns out we had been printing labels and a sticky label had got stuck over
a hole in the mylar shield.....

> I think Data Products made the printer we got for our Modcomp IV
super-mini
> computer back in 1974 at the U of Illinois.  It was a chain printer, and
we went
> out of our way to get a printer that handled the full 96 characters of
ASCII,
> Upper and Lower case.  My only print sample for that printer is my MS
thesis:
> -- http://homepage.cs.uiowa.edu/~dwjones/plato/JonesMS.pdf
> 
> I had to overprint each line 5 times (using a new ribbon) to get print
quality high
> enough to submit as a thesis.  Unlike drum printers, this one never had
jitter
> problems (they'd be horizontal jitter on a chain printer, not vertical
like a drum
> printer).  We used the printer fairly regularly for 6 years before I left
the U of
> Illinois Medical Computing Lab.  This printer was also about the size of
the desk
> I'm now sitting at.
> 

I suspect IBM had some kind of patent on chain printers, hence many used
drums.

>            Doug Jones
>            jones at cs.uiowa.edu

Dave
G4UGM