Introductions
The TRS-80 Model 1 was introduced to Japan in 1979, with a custom keyboard and Kana support. The keyboard PCB and ROMs were completely different. In order to support the Japanese Kana characters, multiple changes were made to the ROM, resulting in a larger ROM size and an extra ROM chip on board. One side effect of this is that none of the original DOS programs work on the Japanese TRS-80 Model 1, as the ROM layout and usable memory allocation are different. A special TRSDOS (CAT. NO. 26-7113) was released in Japan to handle the different ROM mapping. Until now, I have not found any archived copy of DOS that works for the Japanese TRS-80 Model 1.
Acquisition
I was initially unaware of the hardware differences. I already had the Japanese TRS-80 Model 1 on hand but didn’t yet have an Expansion Interface or Disk Drive. I actively kept my eyes out to see if one would go up for sale. Last year, a disk drive was listed as junk up for auction in Japan, which I purchased. I was pretty lucky to have won the auction as the only bidder, the cut-off power cable probably helped keep the price low.
When the disk drive arrived, a floppy disk was stuck inside. I removed the drive cover, pulled the floppy out, and set it aside for the future to see if there was anything interesting on there. At the time, I didn’t have an Expansion Interface yet, so I wouldn’t even be able to test it, although it did look to be in dire shape.
Several months later, I finally got my hands on an Expansion Interface unit. At this time, I noticed that none of the existing DOS programs would boot on my Japanese TRS-80 Model 1. I then realized the importance of the disk that was found stuck in the drive; there was a small possibility that a copy of Japanese DOS existed on it.
I didn’t just want to put the disk in to check what was on it, as just attempting to boot from the floppy could damage the contents. I instead needed to get the disk dumped. Joseph from the Game Preservation Society was able to help out with this. There was a noticeable amount of mold on the outside tracks of the disk. After cleaning the disk, the first attempt of dumping the disk resulted in several errors on track 0. But from looking at the contents, we were able to tell that this disk indeed was a copy of TRSDOS. After a second round of disk cleaning with stronger chemicals, we were able to read and dump the disk contents without any errors fully!
Now that we had the disk dumped, I went ahead and tried to boot from the disk. To my delight, my Japanese TRS-80 Model 1 was able to boot into TRSDOS v2.3 successfully!
Disk Contents
Upon booting from the disk, you’re welcomed with the TRSDOS v2.3 welcome screen
One of the interesting things on the disk is the TEST1/CMD program. It tests the Kana ROM on the TRS-80,
I’ve made the disk available for download in four formats. The original HxCStream dump, as well as HFE, JV3, and DMK. Most users will likely want the JV3 or DMK format. The JV3 file was exported via HXCFloppyEmulater, and the DMK was generated by converting the JV3 file using Applesauce.
I’ve also converted the disk into WAV format for use with Jürgen’s Bootstrap utility. This is for those users who’d like to create a physical floppy disk directly on their TRS-80 using the cassette audio input.
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