• Please review our updated Terms and Rules here

DEC PCP-11 Laptop

L

leeb

Veteran Member
Joined
Jan 21, 2009
Messages
709
Location
Palm Springs CA
I spend most of my time in the Tandy section, but I recently acquired a PCP-11 Laptop...
It is a mechanical duplicate of the Tandy/GRiD 1755, one of which I got 'sometime back'... both of which is a rebranded Panasonic...

Unfortunately it also suffers from the power-up issue common to many of the models that use the 16 to 5/-22v converter such as the (tandy) 2810/20 etc., its immedate relative, the Panasonic CF-270 (Business Partner), the aforementioned GRiD and, I suspect, some others.
It also had the expansion RAM card installed as well as what appears to be a good modem, subject to test.

Although the design of the PCP11/1755 is significantly different than the 2810/CF270, I am certain that there is ONE SIMPLE fix that will restore all these machines... and I only need to put enough 'free time' into finding it.

Which will happen soon enough, as I get to go on temporary medical disability during/after the scheduled stem-cell bone marrow transplant coming up soon!

Hopefully before the end of the next year I can publish a 'fix' for all these excellent (IMO) machines!

:D
 
When I first read this thread, I thought I saw "DEC PDP-11 Laptop", and the concept was mind-blowing. On second reading I suspect it's an x86 laptop in DEC clothing, but I still hope you can fix it. Is it this one?

eBay listing 271337752594

If so, then I'd say you got a good deal on an uncommon (?) pig-in-a-poke computer project. Looks neat!

Now, somebody please tell me that there was an actual PDP-11 laptop. If not, then we MUST invent one! Or maybe a VAXtop… :crazy:

Hey, I hope your procedure goes smoothly!
 
Yes... IMO the shipping was WAY high, but fortunately for me noone else bid on it, and I didnt ending up spending a Benjamin on it.

I too thought PDP when I first saw the listing, then assumed it was of the '2830' type... the 386 version of the 2810/20... possibly with the 35-pin RAM in it...
Nope.

IF IT WORKED I would say I got a good deal. At least I have a new clock/battery to put in it (an extra from the 1755 replacement) :D

Would a PDP-11 laptop be so difficult in these OMG-fast chip days? Admittedly I dont know enuf about them to venture...

Tho a 10" touch-screen VAX would DEF be a cool addition to the menagerie which is my computer (dead & alive) collection! :D
 
I think that it would definitely be do-able to implement a PDP-11 system in an FPGA, and cram it into some repurposed laptop case. It wouldn't be trivial, but it would be possible. Battery life would probably be poor, but who cares? :)

Even a VAX 11/780 should be do-able, and it would probably be practical to run it 10x-100x as fast as the real iron. But I wouldn't. It would run at 1.0 VAX MIPS, dang it! :)
 
PDP-11 in an FPGA has already been done by a number of folks. VAX in an FPGA is a different beast altogether however. I am not aware that anyone has even attempted to do such an implementation

That being said, there is really no point in doing custom hardware design. Take any recent laptop (maybe less than 10 years old) and run SIMH on it on top of Windows and/or Linux in full screen terminal mode. This would give you any PDP that is emulated (8, 11 or VAX, plus other older models) at much greater than legacy performance. No hardware design required.

By the way doing a hardware implementation of a PDP-x in an FPGA at a performance level that can come anywhere near that of SIMH running on a modern X86 CPU is a non-trivial design effort. Getting an FPGA implementation of a PDP-x to run 10X faster than legacy hardware is possible with some reasonable level of effort. However SIMH will get you 50X to 100X faster on a 3+GHz CPU.

Don
 
NF6X said:
When I first read this thread, I thought I saw "DEC PDP-11 Laptop", and the concept was mind-blowing.
Click to expand...
I have to admit I did the same and thought "A pdp-11 laptop?". Cool. Then I realized what I had done. But still sounds cool. Good
luck with it.
 
Running SIMH on a regular laptop would certainly be a more practical solution than building custom hardware, but it just doesn't excite me at all.
 
Shoulda complained sooner?

Shoulda complained sooner?

Now that Ive been here byching about the 'dead' PCP-11...

I managed to get it to come up last nite!!! Multiple times!!!
Obviously I need to pull the board and look at solder connections... wiggling the power connector has been able to get it to power up.

A bizzare situation that Ive never considered trying to duplicate on any of the other machines. This may be some fluke of a problem, but...

The 80Mb HD (Conner) that came in it sounds like it may be having spin-motor problems... but comes up so far!
NONE of the usual device-specific setup software seems to exist... hopefully the 1755 config program is compatible. (Likely so)

So far, :D
 
Cool! Hmm, once you get it working reliably will you run SIMH on it? Despite what I posted above, something about simulating DEC hardware on a DEC-branded laptop seems proper to me.
 
Dont see any reason I couldnt...
386-20 CPU, (too slow perhaps?)
Plenty of RAM available (not yet counted),
Have various DDO-ed large drives available.

Just have to confirm that I still have the 1755 config software and that it DOES work on this board, and then swap out the old DALLAS clock/battery for the new one.
Of course Ive NEVER used a PDP-11/VAX so Id have NO CLUE what to do with it... :rolleyes:

... I wonder how hard it would be to rewrite VAX/VMS for the ARM chips? :rolleyes: :cool:
 
Last edited:
>Now, somebody please tell me that there was an actual PDP-11 laptop. If not, then we MUST invent one! Or maybe a VAXtop…

At a long long ago DECUS symposium (mid 80s or so), the DEC group that was responsible for the T-11 chip (the group was called something like the Technical Volume Group) had a prototype PDP-11 laptop system they were using to showcase the T-11. It had a 8 or so line LCD text display and was running a modified RT-11. Unfortunately, it never became a product. It's a shame, it would have been a handy little system.
 
You must log in or register to reply here.
Back
Top