Help me! Before I take the plunge

[vrs]

> 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

Well, sort of halfway between :-).

There are also smaller, cheaper DECmates, too.  My experience is mostly with
the DECmate III.  (Hopefully someone will correct me if something I say
doesn't apply to the DECmate I.)

> 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?

That's a subjective call.  However, if I didn't already have two (well, one
and a half, really), I'd be interested.

> Is technical documentation available?

Yes.  Too lazy to look up the URLs, but they aren't hard to find.  I think
the hardware info (at least) is available at bitsavers.

> What OSes will run on it? (OS/8 ?) Are they available for download?

There's a special version of OS/8 for DECmates, I think one of the other
OSes also runs on DECmates, but can't remember offhand which it was.  It
usually comes with a word processing system.

Yes.  I downloaded a bunch of floppy images a while back.  The trick will
probably be getting something to write the funky 8" floppies.

> What software, languages, assemblers, etc. are available?

> How compatible is it with the PDP-8 -- i.e., will it run PDP-8 software?

There is a silly incompatibility in the keyboard interface that can cause
characters to be lost with some programs, and I found a bug in the console
output firmware on a DECmate III that required a 1-word patch to Focal '69
to work around.

There is no EAE (extended arithmetic instructions) in a DECmate I, and that
software will hang if you try to use it.  Also, a lot of software used to
use the switch registers, and used to halt to let you look at the lights or
change the switches.  None of that will work, since the DECmate I cannot
continue from a halt.  (Since there aren't any switches or lights, you
likely wouldn't try to run that stuff anyway.)

Most of the programming languages and sort of mainstream stuff will probably
run (possibly with minor tweaks).  All the process control and funky
hardware stuff is (naturally) hopeless.

> Does it have a free serial port so I can download software onto a PC and
> then serial-transfer it to the DECmate?

It should, but you might need a DP278 board.

I think the 12 bit Kermit stuff is used for this kind of file transfer.

> How expandable is it?  What sort of bus does it have?

I understand there was an RL02 controller, and some COM (DP278) boards, for
the DECmate I.

> What are the DECmate's disadvantages?

Various minor software incompatibilities, mostly with the console interface.
Most of them have been well documented.

> Is there a better machine I should hold out for which is small and in
> the same price range?

The DECmate II is about the size of a large old fashioned PC-AT.  The
DECmate III is smaller (makes a fine stand for the monitor), but has no
second drive bay, so you get just the dual floppy drive it comes with.  Both
of these use 5.25" floppies in RX50 format instead of 8" floppies in RX01
format like the DECmate I.  Both come with a communications port.

IIRC, both these machines take coprocessor options which can run some flavor
of CP/M.  The DECmate II takes an option for a MFM hard disk.  These option
cards are pretty hard to find, if they don't come with the DECmate when you
buy it.

> If it has problems, are there people on this list who will help me
> troubleshoot the thing (I have a 'scope, logic probe, meter, soldering
> tools, etc.)?

Should be.  I've used my DECmate III a bit, debugged around some
compatibility issues, etc.  I haven't got 'round to trying out my DECmate I,
though.

    Vince