17 Jan
2010
17 Jan
'10
7:25 a.m.
Part of what makes them desirable is
that they are now over 40 years old and when found, usually complete
enough to run and quite portable.
Portable, yes. But also quite useless. You can
add peripherals to the IO bus - if you have them. But
you cannot run OS/8 on the machine. For that purpose you'd need an expansion box with
further 4K.
And then you're at the 8/L's maximum. AFAIK the basic system can be fitted with
paper tape
interfaces. That makes it a bit more usable. If you have the bare machine, you can toggle
in
programs and run paper tape software and - very important - spend your day waiting for the
teletype
to read in your program.
They use individual TTL chips, so they are somewhat
easy to repair
(I've fixed several), and of them have core memory (unlike later
models which might or might not).
Core memory was quite common with /e/f/m systems
as well! Even the /a sold with core. But I have no
info about the relation between /a with and without core.
My first -8 experience was with an -8/L. As I've
posted many times
about this exact model, in 1982, they weren't expensive (mine cost $35
and some swap goods) because they were "old". Add 28 years of demand
going up and the supply going down and you have these sorts of prices
(others, perhaps on this very list, had similar experiences with the
PDP-8/S a few years before that - same effect, but with more
scarcity).
I initially only played with my Honeywell H316. One day I got a call
that someone had a pdp8/l to
dispose. After arrival it came out that there were three machines. Quite rotten, but
complete. I
saved them. One of the machines was in a partially runnable state. It has been completely
restored
to stable operation in fall 2009 - by a retired DEC field service engineer. He liked to do
it. And
he will probably fix the other two machines as well.
So pdp8/l was my first (own) pdp8 experience as well. I rescued them only to demonstrate
the
difference in quality between Honeywell and DEC stuff :-)
But with time I realized that the fact that the DEC stuff was very widely sold and that
therefore
the internet is full of /8 software makes the /8 very interesting.
I added some /e/f/m style machines to my collection and play with them - if I just
don't fix
something. Currently fighting a pile of TU56 and RK05 drives which need some care to get
working.
I'm quite curious about the 8/i's end price on eBay!
Philipp
--
http://www.hachti.de