On Mar 31, 2005 4:27 PM, Glen Goodwin <acme at gbronline.com> wrote:
Okay, so out of curiosity I found the listing for the
Decmate on eBay:
Now, this is a pretty cool looking critter.
Please bear in mind that I'm essentially an 8-bit
However, the Decmate has a number of appealing qualities:
Small size -- will fit in my HideOut (computer room)
"Somewhat" PDP-8 compatible -- a whole new world for me
Affordable -- even with shipping it's within my budget
Attractive appearance -- looks like a computer my wife can relate to
instead of some gargantuan refugee from a '50s sci-fi movie
It is smaller and cheaper than, say, a PDP-8/e...
On the other hand, I have some questions (I did a
little Googling and
have more to do, but I know there are folks here who can answer my
questions quickly and accurately):
Is it a fair value at $200 plus (probably) another $200 for shipping?
Others have chimed in, but let me put it this way... _I_ didn't
consider a bid for it.
OTOH, if one has a number of DEC machines, one can one or both of the
RX02s in the pedestatl with, say, a PDP-11. They are indepenent, BTW,
so one could hook one RX02 to the DECmate, and the other to a MINC-11
(same DB-25 external cable pinout).
Is technical documentation available?
Yes, on bitsavers. I was just reviewing the docs for it the other
day, and the schematics look complete.
What OSes will run on it? (OS/8 ?) Are they available
OS/278 has the necessary patches to deal with the differences in the
console IOT behavior that was well described in another post. Dunno
about download, but you'd have a problem with the downloaded file,
since the RX02 format can _not_ be written by a PC FDC (it's a hybrid
format that only the RX02 drive (and DEC-compatible 3rd-party
drives/controllers) can write.
What software, languages, assemblers, etc. are
Once one has OS/278 up, the list is the same as for OS/8. Primarily,
folks wrote in FORTRAN or 12-bit MACRO, but there are a few other
How compatible is it with the PDP-8 -- ie, will it run
Yes, except for the aforementioned console incompatibilities. It's
not hard to tweak stuff to work with the DECmate, but stuff that does
its own console IOTs _does_ need to be slightly tweaked. Much easier
with the MACRO source than without.
Does it have a free serial port so I can download
software onto a PC and
then serial-transfer it to the Decmate?
I don't remember. If one has the communications board (DP278?), one
has the spare port for sure. The only problem then is a
chicken-and-the-egg problem... how to get a program into memory
without already having a program that understands that protocol. The
quickest answer (but not necessarily the easiest answer) is to get a
bootable RX02 disk with Kermit on it.
How expandable is it? What sort of bus does it have?
It is in-cabinet expandable only... the available options are more
serial ports (DP-278), and an external hard disk (RL278?) I have
never personally held either option.
The bus is a proprietary one, that happens to fit on two slots
mechanically identical to, say, an Qbus. The pinout is described in
the pdfs on bitsavers.
What are the Decmate's disadvantages?
Not console IOT compatible
EAE not possible to attach.
Is there a better machine I should hold out for which
is small and in
the same price range?
DECmate IIs and DECmate IIIs are cheaper... I don't consider them if
they are loaded with standard equipment and priced above about $40.
It's easy to add a hard disk (ST-225, for example) to a DECmate II,
making it attractive. The DM II and DM III also use 5.25" 'RX50'
diskettes which *can* be read/written from a Linux/Windows/etc machne.
There's also the possibility for going with an SBC6120
), but the SBC6120 is *not* cheaper
(but it is smaller and more compatible) than this DECmate I. With
front panel and I/O board, I have several hundred dollars in my
SBC-6120, but at the moment, they are a lot rarer than even the