These days, the vast majority of portable media users are storing their files on some kind of Microsoft-developed file system. Back in the 1980s and 1990s, though, things were different. You absolutely could not expect a floppy disk from one type of computer to work in another. That is, unless you had a magical three-format disk, as [RobSmithDev] explains.
The tri-format disk was a special thing. It was capable of storing data in Amiga, PC, and Atari ST formats. This was of benefit for cover disks—a magazine could put out content for users across all three brands, rather than having to ship multiple disks to suit different machines.
[RobSmithDev] started investigating by reading the tri-format disk with his DiskFlashback tool. The tool found two separate filesystems. The Amiga filesystem took up 282 KB of space. The second filesystem contained two folders—one labelled PC, the other labelled ST. The Atari ST folder contained 145KB of data, while the PC folder used 248 KB. From there, we get a breakdown on how the data for each format is spread across the disk, right down to the physical location of the data. The different disk formats of each system allowed data to be scattered across the disk such that each type of computer would find its relevant data where it expected it to be.
It’s a complex bit of disk engineering that allowed this trick to work, and [Rob] explains it in great detail. We love nitty gritty storage hacks around here. Video after the break.
[Thanks to Mathieuseo for sending this in!]
Would be fun if you could write your own double format disk. (I’ve looked at the video and it seems that the DOS and ST use the same FAT12 portion of the disk. The format is better then the previous he featured and seems more mature.
I remember from my ST days that the ST floppy format was very nearly compatible with that for DOS – to the extent that you could use a DOS format floppy in your ST (but not vice versa).
Once I took the magnetic disk out of a (hard) floppy and added it to another then tried to get a school computer to read it but.. it just jammed everything up. I was like 8 & never used one before so cut me some slack lol.
Old school hardware hacks are always an interesting topic to look into.
A slight nitpick here… the vast majority of mobile media uses these days are likely using their phones, not a pc – and as the top two players in that market are both *nix based, that statement is probably incorrect.
And yet, an android phone cannot mount an ext4 flash drive…
Or NTFS most of the time, despite using either ext4 or f2fs internally. This isn’t a bug, it’s by system policy since Android 5. Is it stupid? Yes, but that’s a different issue.
Note that having NTFS support is pretty uncommon itself, and some devices don’t allow exfat either, it’s entirely dependant on the vendor.
I found this out yesterday after formatting a new flash drive. I don’t get why Google has done this. Why should I need to use a FAT partition on my *nix based mobile computer
“Portable” not “mobile”.
Oh the wonders of all that storage space on a 720kb floppy, and then the mindblowing excess of the 1.44Mb successors.
As I explained to my daughter when she got her first MP3 player, a 3.5 inch floppy can hold about half a song. That’s what she found mind-blowing!
880kb and 1.96Mb for the Amiganaughts out there.
Oh, I miss my Amiga 500.
Hes refering to fat32 not ntfs thats on 99% of mobile devices
The Cat-Weasel floppy drive! I have fond memories of this. It allowed PC/ST and Amiga formats on one drive.
I miss those simple times.
the amiga system will have been tip top,
it’s too bad they don’t sell integrated pc versions now