Olivetti M10 with Interesting PicDisc Drive
I recently found and acquired an interesting peripheral for the Olivetti M10 portable computer. It is one of the “Model T” computers including the TRS-80 Model 100, NEC PC-8201, Olivetti M10 and the Kyocera Kyotronic 85. The PicDisc was made by Personal Integrated Computers in California, USA in the mid 80s when CP/M was still a somewhat viable option. The IBM PC was taking over at the time so a portable CP/M computer add-on for the Model T computers was
PicDisc advertisement.
likely a bit of a hard sell.
That said, the scarcity of these peripheral add-ons does make it a challenge for vintage computer collectors in finding one. Seeing one work is a whole other level. I saw this in an eBay auction in mid 2026 and didn’t really know what it was. What I saw was an Olivetti M10 computer with a 3.5″ floppy disk stuck on the side via a bottom plate that tied everything together. It was also in a briefcase. I don’t know about you but if I see an interesting vintage computer in a briefcase, I’m in.
There was no documentation or power supplies so that could present a challenge. I did a Google search and other than some advertisements that I found later, I only found two references. One was a forum post trying to sell one because they couldn’t get it to work and the other was from a person who had one back in the day that had posted disk info for the 22Disk program. The key to this would be to find the software that would go with this. I knew it was CP/M based and there was probably some sort of option ROM. Since it was in a briefcase packaged with an Olivetti M10 stuck to it, I was hopeful it was there.
The auction also came with a puzzling array of software. It was mostly early IBM PC business software but there were three or four diskettes that looked somewhat promising because they were single or double sided, double density 3.5 inch diskettes and that’s what the PicDisc would have used. The rest were high density 3.5″ MS-DOS based software disks that would
definitely not have been used. One of the disks had a handwritten label that said “T-Maker”. This was one of the pieces of software that was an optional purchase with the PicDisc so as I patiently waited for the PicDisc unit to arrive, I was praying it had CP/M on it too.
If it had not had CP/M on it, I’m not sure if I could ever find the software for it but it was worth a shot. For what I paid for it, the Olivetti M10 was worth the cost so it would not
have been a loss. I have a few items in my collection that are waiting for me to reunite them with something. It might be hardware parts, peripherals or software but those all await a very specific discovery of the missing item.
One of the PicDisc auction pictures.
Being that the M10 and PicDisc were in a briefcase, I figured it was relatively safe in transit so I did some digging while I waited and found a couple of ads (one above) and an article on the PicDisc being compared to the Chipmunk disk drive; another 3.5″ floppy disk drive that competed with Tandy’s Portable Disk Drive. It gave me a few hints. One of them being that I had to start it up with a one line BASIC program. That was going to be a problem with no documentation.
Well, the computer and disk drive finally arrived. I put some batteries in the Olivetti M10 and looked to see what would happen and nothing… I would have been more surprised if it worked, to be honest.
When it arrived, it had a bad battery. It was a rather beefy 12 volt DC 1.2 aH battery that I am certain has been dead for a while. I was able to find a
replacement relatively cheaply. The main PIC F-100 Controller board appeared fine but this is a small power supply board on top of the battery (not shown in the picture on the right) that had two diodes in parallel. One was open so I replaced that. While I waited for the battery, I tried to power up the M10. On the back of
PicDisc internals with battery
the PicDisc unit is a barrel jack. I now believe it’s a 12 VDC charging plug for the battery but I didn’t know that at the time. There is a makeshift wire with a barrel jack of the same type that connects to the battery leads of the M10. I thought, perhaps, this was the to be plugged into the PicDisc but I no longer think so because the M10 battery pack would be 6 VDC and the PicDisc needs 12 VDC. Well, I plugged it in anyway and fired up the M10 and it complained that the battery was low and shut down. It had life!
To make a long story short, I installed the 12VDC battery, blew the internal fuse at some point (maybe it was already blown?) and rather than use the batteries, I used a 6 VDC power adapter for the M10. That made it work, mostly.
I was getting garbled text when typing so the caps that I had previously inspected in the M10 that seemed okay, were replaced. They were not okay but it still did not fix it. Glad I replaced them anyway. The issue was with one of the keyboard ribbon cables internally. most of the metal bands has split at the flex joint closest to the connector so I cut it off, scraped away at the ribbon cable to essentially make a new connector and plugged it in. Now it is working perfectly.
PicDisc on Olivetti M10
While I waited for parts, I also archived four diskettes that looked like it might be for the PicDisc. Two were Single Sided Double Density (SSDD) and two were Double Sided Double Density (DSDD). Thankfully, I was right. I think three of the four had CP/M 2.2 on them but only minimal files. One was a data disc with some random T-Maker files (I think). This was also a bootable CP/M disk but exploring the disk image, it was a DBase II diskette that had all the files deleted (file names started with E5) and five or so word processing files written to it. I had to manually modify the disk image to replace the E5 with whatever the first letter of the file should be. Through this method, I was able to recover most of the CP/M files. I didn’t bother with the DBase files.
One of the files on that disk was MBASIC.COM or Microsoft BASIC. I gathered some Microsoft BASIC sample programs and they ran just fine. I now have two PicDisc disk images if anyone needs them. One with CP/M for the PicDisc and the files I could recover including a Modem program that I assume is custom written for the PicDisc and the TRS-80 Model 100. That would have been super useful but I used the 22Disk definition I previously mentioned to manipulate the floppies so I can copy anything to a disk. FORMAT and SYSGEN were some of the recovered files so I can make as many bootable CP/M diskettes as needed. The other is a bootable CP/M disk with MBASIC and sample programs.
The interesting part of the PicDisc is how it works. I spent some time trying to figure out voltages because I knew that the Teac FD-35E 3.5″ single sided drive mechanism would need 12 VDC and 5 VDC for its operation. I determined that 5 VDC was coming from the ribbon cable that connected the M10 to the PicDisk through the expansion connector on the bottom of the M10. We knew the battery is 12 VDC so the two voltages exist but they don’t intermingle in any way and
PicDisc/Olivetti M10 bottom
that was what I needed to confirm to determine the voltage needed for the PicDisc power jack. It’s just a straight 12 VDC and the label on the bottom of the PicDisc unit (that had fallen off and I later found in the briefcase when I cleaned it) showed is needs a 12 VDC 400 mA adapter. It doesn’t need a power adapter to run, it needs it for charging. The Olivetti M10 should be able to run on the 4 AA batteries to make it a truly portable CP/M 2.2 computer but I mainly used the 6 VDC adapter during testing. The mystery remains on the plug that is wired to the battery terminals. It looks like you can plug in into the PicsDisc jack and the advertisement above says the PicDisc is “rechargeable during use and powers your computer”. I don’t see how that would work unless the PicDisc jack is used with that plug that goes to the batteries but I measured that at 12 VDC. Unless the M10 can take 12 VDC for power, I don’t see how that would work. It’s not something I am willing to try right now. For that I really would love to have the PicDisc documentation that I do not have.
So for the “Model T” computer fans out there, here’s how it works from the software I have been able to find. As far as I know, the PicDisc only does CP/M 2.2. There is a custom ROM that fits into the M10 and replaces the Microsoft ROM at location M12 on the motherboard. This has almost nothing in it. At first glance, I thought it was corrupt but all it does is tell the PicDisc to boot a CP/M on diskette. I referred to a little BASIC program in one of the reviews. I guess at some point they decided to scrap that method and replace the Microsoft ROM with code that fires up the PicDisc on startup and looks for CP/M. It’s possible the software I am missing allow the normal Model T environment in some way but if it does, I haven’t experienced it. As far as this computer was used, it was strictly a portable CP/M computer.
One thing I did find was that the display has a 60 characters per line via a custom font and the normal 8 lines but the arrow keys allow panning and scrolling to 80 x 24 like normal CP/M software might expect. This makes it compatible (although a little kludgy) with a full screen display so compatibility with CP/M software would be quite high. Without documentation, it’s hard to poke around and see what you find so I’ll leave it at that for now.
I would really love to find the original software and manual for the PicDisc. If anyone has any of this, please contact me through the “Contact Us” link above.