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> Commodore produced a great many Amiga models, but for several years the gold standard was an Amiga 500 expanded with half a meg of RAM (bringing the total to

> Commodore produced a great many Amiga models, but for several years the gold standard was an Amiga 500 expanded with half a meg of RAM (bringing the total to a full megabyte) and an external floppy drive (bringing the total number to two) Indeed, I had that very setup, but with a little twist... I still have my very weird oddity which is an external, non-official, 5"1/4 (not 3"1/2, like most people had) floppy drive. Among our group of friends we'd all do that because, at that time and in the EU at least, 5"1/4 floppies were so much cheaper than the 3"1/2 ones that for the price of about 3 boxes of 3"1/2 floppies we could buy 3 boxes of 5"1/4 floppies and the external 5"1/4 floppy disk drive reader (which I take it were assembled by amateur/hobbyist: they didn't look anything like official drives and were very raw, bought through friends-of-friends-of-friends). Now that Amiga Internet forums are flourishing people have accepted that this was a thing (there are even rare pictures of the thing) but in the past I've had Amiga users explain me that this didn't exist and that I was seeing things (!). To make the matter even more confusing Commodore did sell official 5"1/4 drives for the Amiga too, but these were different. The "bootleg" 5"1/4 were, for all matter and purpose, identical to the 3"1/2 ones and we'd install a switch on the Amiga to decide if we were booting from the 3"1/2 or 5"1/4 and the OS had zero way to tell the difference.

ekianjo 3y ago
So these disks had the exact same capacity? or could fit more data?
- TacticalCoder 3y ago
  In practice, it was the exact same identical capacity. The OS couldn't see any difference. We'd use them as exact replacement of the 3"1/2 disks. So we'd use them as double-sided 880 KB floppies.
- snvzz 3y ago
  The track format is what is different. Note that in a PC, the controller abstracts the tracks from the operating system. You read and write sectors, floppy controller does everything. In an Amiga, the controller reads and writes raw data, full tracks. CPU does handle the format of the track. The track format is described in chapter 2 of the ADF FAQ[0]. The main reason it is more efficient is that there's no gaps between sectors; only one gap after the end of the track. This is because the Amiga way is to read or write a full track, starting at any sector in the track. One reason the PC's controller does not do this is the cost of RAM when the PC was introduced. A full raw track takes a significant amount of memory. 0. http://lclevy.free.fr/adflib/adf_info.html#p2 http://lclevy.free.fr/adflib/adf_info.html#p2

ekianjo 3y ago

So these disks had the exact same capacity? or could fit more data?

TacticalCoder 3y ago
In practice, it was the exact same identical capacity. The OS couldn't see any difference. We'd use them as exact replacement of the 3"1/2 disks. So we'd use them as double-sided 880 KB floppies.
snvzz 3y ago
The track format is what is different. Note that in a PC, the controller abstracts the tracks from the operating system. You read and write sectors, floppy controller does everything. In an Amiga, the controller reads and writes raw data, full tracks. CPU does handle the format of the track. The track format is described in chapter 2 of the ADF FAQ[0]. The main reason it is more efficient is that there's no gaps between sectors; only one gap after the end of the track. This is because the Amiga way is to read or write a full track, starting at any sector in the track. One reason the PC's controller does not do this is the cost of RAM when the PC was introduced. A full raw track takes a significant amount of memory. 0. http://lclevy.free.fr/adflib/adf_info.html#p2 http://lclevy.free.fr/adflib/adf_info.html#p2