An Ancient 8 Inch Floppy, With A PC

Most of us may have gratefully abandoned the floppy disk a decade or more since, but even today many PCs and their operating systems retain the ability to deal with these data storage relics. The PC was widely fitted with either 5.25″ or 3.5″ disk drives, but other formats such as the older 8″ discs were not a fixture in the 16-bit desktop computing world. It’s something [Jozef Bogin] has taken aim at, with his exploits in connecting a variety of 8″ drives to a PC.

In the early 1970s there were a variety of different 8″ drive standards that weren’t all entirely compatible, but a de facto standard emerged as clones of the Shuggart drives used by IBM. It’s a modified version of this interface that can be found in a PC floppy controller. While there is enough electrical compatibility to connect the two there remains a variety of connectors used on the drives. There are also a wide range of power supplies, with drives requiring 5, 12, and 24 volts, and some of them even requiring AC mains with different versions for 50Hz and 60Hz mains frequencies.

With an 8″ drive hooked up to a PC, how might DOS, or even older Windows versions, interface with it? To that end he’s created a piece of software called 8format, which not only allows 8″ disks to be formatted for the PC, but also provides a driver that replaces the BIOS floppy settings for these drives. This doesn’t work for imaging disks from other older platforms, but he provides pointers to more capable floppy controllers for that.

If these drives interest you, there’s more to be gleaned from a tale of interfacing them with 8-bit retrocomputers.

41 thoughts on “An Ancient 8 Inch Floppy, With A PC

      1. About fifteen years ago I found a box of 8 8 inch outside a church after a rummage sale.

        It really made me wonder if I missed something very interesting, or if they only got the box of floppies.

      1. I got that beat. Loaded OS/2 2.x from floppies, followed by the Warp 3 upgrade – onto a Packard Bell 486 with a 63 Mhz Pentium Overdrive. It had a curious problem where if I wasn’t *constantly* moving the mouse while it was copying files from the disks during install, it would crash and I’d have to start all over. Crashed on me 3 or 4 times. But once I finally got it installed it was fine. Don’t recall how I figured out that keeping the mouse moving kept it from crashing.

  1. When I was student, some poor guy put up a sign in the computer lab, offering a reward for the return of the 8-inch floppy he had left in the PDP-8, but missing when he went back to retrieve it. It contained (obviously) the only copy of his term project, and he desperately needed it back.

    Word is he eventually got a printout of the contents of the floppy. In octal.

    1. At university in the early 1980’s, I saved my Pascal programs that ran on a PDP-11 on an 8” floppy disk. Kept that disk for many years afterwards but, alas, I eventually tossed it in the bin. :-)

    1. Nice… possible even 22Nice (CP/M to DOS utility joke) … I been scouring teh internetz for ages looking for a simple ‘duino floppy solution, guess I should just get a bluepill and do this.

      1. That’s 22Disk. 22Nice is the Z-80 emulator, or activator if you have a PC with a NEC V20 or V30 CPU. 22Nice also allows running CP/M on a PC.

        My PCjr with a V20 and using 22Nice ran CP/M faster than a 12 Mhz 80286 (with 12 megabytes RAM, all but 512K on three ISA cards), or a Xerox 820-II.

  2. Perhaps a Raspberry Pi Pico would be a great way to connect floppy drives to modern PCs for archiving data? Or bypass the demod logic and send the raw signal to some ADCs connected to a FX2, in order to try to recover data on degraded disks.

  3. I made a modest side-living building and selling systems with 8″ drives on IBM PC clones.

    I still have a ready-to-ship 8″ drive and cabinet with an ISA “CompatiCard” controller, sitting in the shop. Weighs about 30 lbs, worth about the same (-:

    1. Had a CompatiCard IV. No ISA bus system board now. :( Lucky you! Had it running a Tandon DSDD drive. A Z-80 CP/M emulator under DOS worked with the 128 byte single-density just peachy. *Sigh*

  4. The only dumpster diving I ever did I came out with about 10 8″ floppy drives, a whole lot of 8″ discs and a paper tape punch machine.

    Unfortunately I still have them. They, along with a WWII Radar Head unit, have been holding down the concrete in my basement for 20 years and I’m pretty sure they’re worth less now than they were 20 years ago.

        1. Do you have a dropbox or other link I can post an email address to? I hate to leave an email exposed to scrapers. Or, if you have a disposable, one-time email, maybe post that?

  5. Around 1980 we had an HP-9845 desktop computer that used those disks. It was awesome.

    I had never seen a floppy before. The only non-volatile storage medium I had used was paper tape.

    1. I seemto recall an article about making a punch card reader. But it woukd have been manual.

      People definitely made punched tape readers, and a company sold one to the small computer market. Eight photodiodes, some Schmidt triggers, and a mechanical arrangement to keep the tape straight. You’d pull the tape through the mechanism, and light from a table lamp would be seen by the sensors if the hole was punched.

      The idea being that paper tape was viable for distribution, so some needed to read it, but few needed to punch it.This was just for a few years after 1975, when an ASCII teletype machine, might have been used as a terminal.

  6. A previous missile-making employer used PDP-11/70’s for guidance system test stations up through 1999, the 8″ floppy drives for which were strictly for bootstrapping, the RL02 removable platters doing the real storage work and running RSX-11. 1999 brought PDP-11 emulator PCI card in a rack mount PC. Out went the floppies, but the RL02’s stayed, despite the emulated storage on the PC’s internal SCSI drive.

  7. I used 8″ floppies in an Intel intellec(TM) development system for building PL/M code for a medical device. The “big blue box” had dual 8″ floppies, a bunch of Multibus cards, an 8085 in-circuit emulator, and an EPROM burner. When we really wanted to be exotic, we’d boot CP/M on the machine. The medical device turned out great, but I sure don’t miss those days. Visual Studio and Eclipse, even the Arduino IDE, are so, soo much better.

  8. Been using a Shugart 851 with LINUX just fine. A lot of system boards still had a native floppy port on them, typically with a 765 compatible FDC. LINUX can handle 1024 bit sectors natively, and I use the ‘superformat’ utility (ftools) without a hitch. Even can get 1.6 meg per disk without errors (512 byte sectors) as I have a stash of never-opened discs… The old 50-pin Shugart interface was the prototype and the 34-pin PC interface descended from it. Then only possible issue was with the TG43 line for reduced write current. Thankfully the last generation of 8″ drives would do that automatically. I should try the 8format and see if DOS will then be able to see the FAT file system created with the mformat LINUX tool. Hmmmm.

  9. The very first time I even touched a computer was in the gymnasium of Junior High school. It was 8th grade and the school was seeking to get us exposed to computers. They invited a host of computer vendors to showcase their wares. Many years later, I recalled this event and distinctly remember seeing a Texas Instruments TI 99/4A and for the first time ever I got to touch one of those humongous Tandy/RadioShack TRS-DOS machines that had one or two vertical 8″ floppy drive slots. It is amazing how many years would go by before I came to realize what I had seen that school event: an 8 inch floppy drive! You see, I had only come to learn of and handled 5.25 inch floppies starting with the purchase of a Commodore 64 and 1541 5.25″ disk drive. I knew nothing of the era of computers before a Commodore VIC-20 and Compute! and Compute’s! Gazette magazines. Nowadays I am building a microcomputer from scratch using 5.25″ 360KB and 1.2MB floppy drives.

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