Yes, TRS-80 Day!
I spent most of my time yesterday in building a system that can read my old TRS-80 disks. It's much more difficult than it sounds as the floppy controllers prior to the early 90's worked differently than those of today. Western Digital had the most popular chips (yes chips, not chipsets). Their first chip line (FD177x) only supported single density floppies, and their second chip line (FD179x) supported single and double density. These were not smart chips either. When you formatted a diskette, you wrote the entire track including the filler bytes, and had full control over the sector header to sector data separation.
On top of all that, the TRS-80 used 256 byte sectors like almost all of the other personal computers at the time. When working with an 8 bit microprocessor, 256 byte sectors are much easier to process, thus the reason it was used. None of computers that were purchased in the last 10 years were able to read any of the disks, so I rebuilt an old 486 machine and was able to get it working. The biggest problem I had was creating a set of MS-DOS 6.22 disks. The disk writer that comes packaged with the MSDN download only works from DOS. It will not work from a DOS window or Command Prompt window.
You might be asking, "Why the hell is this guy trying to read those damn old TRASH-80 disks?" For those who don't know, TRASH-80 was the affectionate name given to us by Apple users. Well, here are some links to tell you why:
I started with a TRS-80 Model I with 4K RAM and Level I BASIC, went through quite a few upgrades and in the end had a Model 4 with 128K RAM. I probably spent 90% of my free time from 1978 through 1979 (sophomore and junior years in high school) at the local Radio Shack until I got my first computer. I went to OCTUG (Orange County TRS-80 Users Group) every month and showed off my latest wares. If you saw a 6'3", 136#, blond haired, blue eyed guy there, that was me. Do any of you remember BBGS, KEY-80 or SYS29 for NEWDOS80? Well, I wrote them. I also made my own Orchestra 80/85 boards, CPU accelerators, Floppy Controller, and Clock card.
Anywho, I need to get back to extracting all of my disks, but I wanted to get this posted while I had a few minutes. I spent a lot of time on some algorithms way back then, which I want to convert to C# and reuse. If I'm successful, I'll post more about.