How to format 720K floppies in todays PC's

Floppy disksThe humble floppy disk has powered the Amiga family, Atari ST family, and its successors for years, providing file storage and programs for countless people, along with the ability to move files long before the invention, never mind adoption of USB flash drives. But while floppy disks are still available and most floppy drives will read them, many newer operating systems no longer format 720K disks and support is slowly dwindling.

Or is it?

With the launch of Windows XP, it was announced that while XP would read 720K floppy disks, formatting and writing to them was not supported. As it turned out you could still write data, but all formatting options wre removed, so unless you had a program on the ST that would format to PC standards, or a later version of TOS, you had to sacrifice a disk that you knew the PC would read to get information to your platform of choice. With Windows Vista and Windows 7, the situation remains, though now there is the threat on the horizon to remove support for the floppy disk altogether.

But for the moment, despite rumblings from Microsoft saying otherise, it is possible to format floppy disks for the Atari to use, you just have to know how.

One thing that Microsoft never quite moved away from, and is actually moving back towards in the server products, is the command line, and one of the commands that has pretty much stayed the same since the days of DOS is the format command. So long as you know what format you want on your disk you have always been able to format whatever you wanted to from the DOS prompt, and the same is true today from the newer Windows Command Line.

If you have never opened a command prompt window before and don't know where to start, click on the START button (The round windows logo in Windows Vista and Windows 7) and in the Run box at the bottom, type cmd then press return. The monochrome glory of the command prompt now awaits, this my dear readers was the only way to operate computers before the launch of the Apple Macintosh which itself led to the likes of GEM, Windows, Gnome and many other windows based interfaces we take for granted today.

So what do we do now? We put our 720K floppy disk into the floppy drive and type format a: /t:80 /n:9, which will the format the disk in the floppy drive in a way that the ST can read and understand. To figure out what is happening and why this command works, we need to know a little about the format of a floppy disk.

In the ST and the PC, the 720K format is made up of tracks and sectors, for a normal format it's 80 tracks with 9 sectors per track. The sectors are numbered 0 to 79, which means it is often incorrectly reported that the 720K format uses 79 tracks and confusingly, the sectors are labeled 1 to 9, there is no sector 0. The really confusing bit though is that track 0 cannot be written to normally as it is known as the boot sector, and does include a sector 0. This is used by DOS on the PC to place its boot program, while the ST (And the Amiga) uses it as a boot block for games (And virus programs too, yes the ST and Amiga had a virus problem too).

The principles of the format command is used by programs to get more space out of the humble floppy disk, the trade off being that you would not be able to read the floppy directly in a PC, and if you pushed the format to the absolute limits, the disk could be unreadable in any floppy drive other than the one you formatted the disk in. As an example, one program I used to have could format up to 85 tracks with 11 sectors per track for a staggering 940K of storage from a 720K floppy disk, the downside was that only a few people I knew could read the disks! Messing about with the format command above could also give you a disk with additional capacity, though it will not be readable by the PC, and if you want to copy something on it from the internet, your going to be out of luck.

But it's not just the Atari series that we may need this information for, the Yamaha SY series of synthesizers also used the 720K floppy, as did the Clavinova piano series, Roland's MC500 sequencers and various other pieces of kit need these disks and sometimes you need to format them on a PC to transfer data onto them.

So with the command above, you can once again format floppies on your PC that your ST will happily read, and you can also give your Atari some new software from this very site.

NOTE: This is know to work with internal floppy drives on PC's, however many people are using USB attached floppy drives. None of these devices support all functions of the older built in floppy controllers, though some support more of these functions than others. If this command does not work for you on your USB floppy drive, it may not support the function level required by this command.