calcomp 8" drive motors available

Roy J. Tellason rtellason at
Thu Sep 27 17:50:26 CDT 2007

On Thursday 27 September 2007 18:36, Paul Anderson wrote:
> The Calcomp drives had a cast aluminum frame, while the dec drives are made
> from sheets. The DEC RX02 can be used as an 01 or a 02, while the Calcomp
> was designed to be an 01 only. Some of the earlier DEC drives were stamped
> "RX01 only."

Back in early 1978 was the first time I'd gotten my hands on any sort of a 
real working computer...

The company I worked for at that time bought a Heathkit H11,  and I got to put 
it together.  :-)

Initially,  all we had for storage was paper tape,  which was great fun -- a 
power glitch,  and you had to start all over again,  typing in the boot 
loader sequence,  loading the absolute loader tape,  then the BASIC tape,  
then (if you were lucky enough to have saved something of what you were 
working on),  your saved program.  Later on they got a disk drive,  I'm 
pretty sure a Digital of one flavor or another.  It ran RT-11,  I think 
version 2.

In my initial floundering around one of the things I was playing with was a 
rather crude database,  so they could justify the machine.  Data being stored 
in the form of character strings,  and the software being written in BASIC.  
A big mistake on my part was trying to take a simple sort (bubble sort?) that 
would work on an array of stuff in memory,  and to try and make that work 
with a disk file.

That was the only time I've ever seen TO-220 cased transistors actually melt 
down,  after I went home and left the program running...    :-)

> On 9/27/07, J Blaser <oldcpu2 at> wrote:
> > Chuck wrote: > On 26 Sep 2007 at 17:13, Richard wrote:
> > > > > In article <000f01c8008d$38c89f80$6400a8c0 at BILLING>,
> > > > >
> > > > >     "Jay West" <jwest at>  writes:
> > >> > > > Two drive motors from Calcomp 8" floppy drives are available.
> > > > >
> > > > > Calcomp made floppies?!?!  I thought they just made plotters!
> > >
> > > Nope--my first drives were Calcomp 104's.  Miserable things.  I
> > > believe they were also the stock drive for the Imsai 8080 floppy box.
> >
> > I just finished resurrecting an old PDP-11/03, racked in some
> > old-timer, 1950s-style radio gear cabinet that looks like it
> > came right out of an old NWS monitoring station.  Anyway, the
> > system has two RX01 subsystems.
> >
> > As I disassembled everything for thorough cleaning, I, like
> > Richard, was a little surprised to see that one drive of each
> > RX01 pair was really a CalComp drive.  In both cases the mate
> > was a DEC branded drive.
> >
> > The construction of CalComp and the mated DEC drives are
> > essentially identical, with only a few minor changes to some
> > of the plastic parts.  I wonder if the CalComp line was actually
> > acquired by DEC (or vice-versa?).  These RX01s both date from
> > 1978.
> >
> > - Jared

Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin

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