Retro dual-mode floppy disk discovered in a swap meet bin
Not only did Trixter, an amateur PC historian, find two old unreleased videogame titles in a box of diskettes he picked up at a swap meet, he also happened to find a mysterious floppy that works in both C64 and IBM diskette drives.
The manual for Mental Blocks (see previous message) claims that, for both C64 and IBM, you put the diskette in label-side up. I thought that had to be a typo, since every single mixed C64/IBM or Apple/IBM diskette I have ever seen is a “flippy” disk where one side is IBM and the other side is C64 or Apple — until I looked at the FAT12 for the disk and saw that tons of sectors in an interleaved pattern were marked as BAD — very strange usage.A DIR on the disk shows that only about 256K of it is usable as space, instead of 360K. My Central Point Option Board’s Track Editor (TE.EXE) confirmed that every other track on side 0 cannot be identified as MFM data. So the manual is correct, and this truly is a mixed-format, mixed-architecture, mixed-sided diskette.
This diskette has officially blown my mind.
The diskette that blew Trixter’s mind [Trixter.Wordpress.com] (Thanks, Brett!)
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A discovery like this shouldn't deserve top exposure on the main page of BoingBoing?!
The Commodore disk drives were highly intelligent and totally programmable. The 1571 (5.25") and 1581 (3.5") drives could read and write both Commodore and MFM (IBM & CP/M) format disks. There were people who did even wackier stuff than this with Commodore equipment.
And some of us are still doing it. :)
That's crazy. I mean, like wow, that's REALLY CRAZY. Isn't there some doomsday hell-freezes-ver prophecy attached to this?
Enochrewt: tomorrow, a secret new Amiga will rise from the seas, swinging catweazles, and end man's time on earth.
iAAA, iAAA!
And this is important... why?
If you don't know the shattering importance of a central point option board’s track editor confirming that every other track on side 0 of a 20-year old diskette cannot be identified as MFM data, you really shouldn't be on the internet.
I can't express how disappointed I am in you, Marley.
My bad, my bad. I will call T-online and have them disconnect me promptly.
...There were a few commercial disks that interleaved like that, some were Apple ][, but most were Commode-Door format. Most of them were for swapping between C64 and Apple, and I can only recall two disks that could be read by both IBM and C64. Came across these back in the mid-80's when my consulting company was doing data file conversions from businesses that bought Apple ][s and wanted to move to PCs. Note that the catch was that while the disks could be read by both drives, the data had to be written to both sections of disk. Ergo, if an Apple wrote data the IBM couldn't read it.
Amigas that twirl idiotic time-travelling wizards? At least the endtimes will be interesting.
(you can take my typo in the previous post as a mini-review of a the Microsoft wireless keyboard. Dumb-random-key-non-transmitting-piece-of-shat.)
Catweasel!
http://en.wikipedia.org/wiki/CatWeasel
I spelled it wrong :)
This actually WAS terribly clever. Well, it still IS terribly clever.
There was no way for IBM and Commodore machines to really "share" floppies, since the recording technology was so completely different on the two machines.
The essence of this "hack" is realizing that DOS keeps the basic info about the disk on the first track, while Commodore keeps the data in track 18. So, track 18 tells the Commodore to only use the track that held Commodore data, and that the rest of the disk was not used. The IBM information, however, marked every Commodore track as bad, so they would never used. In essence, this kept two entirely separate file systems living on the same disk.
I like this. It is quite completely and utterly cool
yeah, I have a ¨sounds of slashdot¨ CD with a bootable debian installer on the first track and music on the remainder... I have read it on linux, windows, HP-UX and Mac and I have never been able to duplicate it perfectly with any toolchain.
This IS interesting.
I'd like to think that Amigas will twirl both catweasels and catweazels today. You have to admit, as spelling mistakes go that one makes a pretty awesome mental image.