Emulating the Early Macintosh Floppy Drive(thomasw.dev) |
Emulating the Early Macintosh Floppy Drive(thomasw.dev) |
Pardon my nitpick, but there were two versions of the SE and the author has the dates mixed up here. The original 1987 model had the same disk capabilities as the Mac Plus except it could have two of them installed internally instead of just one on the Plus. Or one 800K drive and an internal SCSI HDD in the other bay — your choice! (Mine actually has all three thanks to a third party internal HDD bracket!)
The FDHD (floppy disk high density) version was released in 1989 as a standalone computer and also as an upgrade kit for the original model containing one (1) SuperDrive, SWIM, updated ROM, and little “FDHD” and “800K” badges to put next to the upgraded and remaining original drives respectively.
The Amiga did its own thing, same as the Mac, but at least it got some extra storage. 880 KB per disk!
(880 KB was also an option on the ST, but only for disks written a track at a time, which was impossible to guarantee if using the OS. With 11 sectors per track, writing individual sectors wasn't reliable as the gaps between them are so small. The OS didn't support irregular disk geometry so you couldn't have more sectors on the outer tracks.)
The variable drive speed comes of the development of the "Twiggy" drive, which was an 850 kB 5.25 disk format originally intended for the Apple III in 1980 but never worked reliably.
BTW, the Atari ST uses the same floppy disk format as the IBM PC, 360 kB per side.
The Amiga uses a variable drive speed like the Mac, but they eke out extra capacity by eliminating sectors. This allows an extra 512 bytes per track, but the trade off is that the disk controller can only read or write an entire track at a time, rather than individual sectors.
An infamous Apple II copy protection scheme used the same trick to expand 5.25 disk capacity from 16 sectors to 18 sectors (512 bytes per track).
Amiga uses standard PC drives with slight tweaked pinout https://linuxjedi.co.uk/2020/12/05/converting-a-pc-floppy-dr...
(18 sectors per track with 256 byte sectors is also possible with the 1770 series. This was one of the disk format options on the BBC Micro. Definitely not written a track at a time! There just wasn't the memory for that.)
Hardware got better really quickly in the 1980's and 90's, including floppy disks. By the end of the 20th century, there were 120MB floppies. Basically Moore's Law seemed to apply to spinning rust for awhile.
In the form of Zip disks, yes. I’m reasonably sure 3.5” disks, the last thing to be called “floppies”, topped out at 2.88M.
In the same way, disk operations themselves are generally blocking and will hand back control to the OS and apps during their read/write cycles so that other things can happen on the computer.
It's a external USB attached floppy drive controller that uses a normal PC floppy drive.
It reads the raw disk stream and software then decodes that for whatever disk format it was. It seems old Mac disks can be recovered with it:
https://www.kryoflux.com/?page=home http://forum.kryoflux.com/viewtopic.php?t=135
Apple got Sony to make cav drives, (MacIIx and SE HD to the 9600 )and when they raised the price, no floppy. Sneaker net was over until USB drives became cheap.
One disk on archive that is unrecoverable is Adobe Type Manager. The areas where the fonts are is corrupted, but the data is available elsewhere, but the program isn't.
Now it sits in the cloud ( someone else's hard disk ) in a corrupted state. Wish I had an SE 30 to restore the disk, and put it's compressed image up as a replacement.
It does not show how kryoflux assists in recovery. They can be archived, and preserved, but not recovered. ( Just try the 800k ATM disk on archive.org )
Or you can get something like a Greaseweazle[1] and go that route if you want to do more advanced extraction.
If Zip disks, CD-R and USB flash drives hadn't showed up, these drives would have been pretty widely recognized as the next generation of floppies.
"Ordinary" floppies peaked in 1988 (yes, before IBM 1990 PS/2 2.88 ED) with 'Triple' or '2TD' format developed and shipped by NEC inside PC-88 VA3. 13MB unformatted, _9,120 kB_ formatted capacity. Triple because it tripled track density from 80 to 240 while reusing ED barium ferrite magnetic media and perpendicular recording head of ED drive, same ~100KB/s speed.
https://necretro.org/PC-88_VA3
https://en.wikipedia.org/wiki/List_of_floppy_disk_formats#:~...
It had a 'click of death'-like failure like Zip did though, and lost the battle during its recall and redesign. (IOMEGA were lucky in that the click of death didn't really kill Zip's market until about the time that CDR/CDRW was beating them anyway)
It was delayed so long that by the time it actually reached the market it didn't get noticed.