Playing with a Panasonic JD-850M


I didn't really want to add anything else to my overflowing computer collection. No, it's the truth! Having over 50 models of various shapes and sizes is a serious squeeze on the computer shack. I now had most of what I considered "the classics". That said, it's hard to pass a boxed 1982 vintage machine when it's offered for free.

Such was the case with this Panasonic JD-850M.

I was alerted to this machine by a friend on the New Zealand Vintage Computer Forums. Essentially it was a rescue mission. This computer just had to go and the owner would rather it go to someone who had an interest in these things than simply junking it. For my part, I never like to see clean supposedly-working machines of this vintage scrapped. The intention was to take it, store it and at some stage give it to someone who had more room than me.

I picked it up at a location about 40 minutes drive from where I live. With the computer came a dot-matrix printer, some manuals for the various business packages and 46 8" floppy disks. Once home it was laid to rest in a dark corner of the garage.

About two months later, I dragged it out for a look....

First Impressions

The first observation was just how HEAVY this machine is. The case is solid steel! No cheap plastics here. It weighs a TON!..easily over 20 KG. I seriously considered my sanity when lugging this thing up the stairs to the computer shack. Had I tripped, that would have been the end of both the computer and me. I wasn't even sure my flimsy desk would support it!

Panasonic JD-850M at rest

Figure 1. The Panasonic JD-850M at rest

It was worth it though. I hadn't realised just what a gem was sitting in that unwanted box. The computer looks GREAT. Practically museum quality. This is due to the fine engineering, the fact it has been looked after during its working days, its proper storage and that there was no white plastic to yellow! The dual 8 inch disk drives are very impressive. Three serial ports and an IEEE- 488 port on the back. All in all it's a very tidy package.

Research on this machine told me it was 64k, ran CP/M and was powered by an 8085A CPU. Those eight inch floppy drives were double sided, 77 track and serviced by a double density controller. They could read and write disks of around 1MB in storage size which was a credible amount in 1982!

Two questions remained. Were the electronics ok and, if so, was there a working boot disk somewhere in the boxes of disks accompanying the machine?

Powering up

Holding my breath I powered on. With machines of this vintage, anything could happen so I had the odds at 50:50 that I was going hear, see and smell the smoky death of a capacitor or two. Even if that didn't happen, surely I was going to see a garbage screen, if indeed anything at all. Actually I saw this...

Panasonic JD-850M boot message

Figure 2. Boot screen

Whoo hoo! It works!!! The image was stable. There was the gentle hum of a fan. The leftmost drive was spinning. It was alive and needed feeding!


So far so good. However, would any of these disks be ok after so long? And where was the System disk?

A quick look through the disk pile uncovered what appeared to be one (and just one) System disk. It was the original CP/M 2.2. disk for the machine. Here is a picture of it with a 5.25 inch and a 3.5 inch disk for comparison.

Floppy disk size comparison

Figure 3. 8 inch disks are big!

But would it work? I pushed the disk in and clipped it home. Immediately the machine sprang to life...

Panasonic JD-850M

Figure 4. Booted and ready to go!

First up was a list showing what all the function keys that line the top of the keyboard do, then at the bottom, the familiar A> prompt. CP/M was once again beckoning a user of this machine after decades of sleep.

Typing "dir" for a directory revealed a host of files...

Panasonic JD-850M CP/M files

Figure 5. Files on the System Disk

All the usual suspects were there (common CP/M files, the Microsoft BASIC Interpreter/Compiler) plus some other utility files. Help.fil was a text file which explained what all these files did.

Panasonic JD-850M MS BASIC

Figure 6. Microsoft BASIC. A common standard on machines of the day

Also on the disk was a Roulette game (essentially this just provides a random 3-digit number and (joy of joys) Adventure or Colossal Cave as it is better known.

Adventure on the Panasonic 850M

Figure 7. Anyone for an Adventure?

The first thing I did was to re-format some of the other disks and make several backups of the System one. There was a damaged track on the original disk so I couldn't do a track by track copy. I had to Sysgen, then pip b:=*.* but eventually I got all the files off and on to a new disk. I then used (track by track) to make several disk copies.

Other disks in the pile contained accounting and record keeping programs from "Interactive Applications Ltd." and the data for these. Interestingly all the programs are written in BASIC. There was also a program disk for testing the printer and head cleaning and an 8 inch head-cleaning disk! Excellent!

It wasn't all good news though. About 2/3 of the disks were IBM and 1/3 were Verbatim brand. The latter were harbouring many fungal colonies. The media on that brand was obviously quite suitable for the growth of these microorganisms. The IBM disks were ok though.

fungal colonies on an 8 inch floppy

Figure 8. Fungal colonies on the Verbatim disks. The IBM disks were clean.


I've just spent several days exploring the machine and the software library with it. I'm so impressed with the solid functionality of the beast that I've decided not only to keep it, but to list it as part of the official collection.

panasonic JD-850M

Figure 9. Handsome and so fine. The Panasonic JD-850M

It's got a lot going for it. The keyboard is great to type on, the screen is crisp and clear and the computer's condition is superb. It's a good example of early 1980s well-engineered Japanese 8-bit technology before the IBM-PC standard started to dominate.

And I've just got to have at least one computer with those huge floppy disk drives!


22nd November, 2013

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