Hyperformat
Hyperformat was born out of a clinical condition known as sector envy.
When I got my first ST,
religious wars waged between Atari and Amiga owners. (Might be amusing
and/or embarassing to revisit those exchanges now...) Every little detail
of the two systems was compared with fervor. Because floppy disks
were the storage medium de rigeur at the time, (floppy) disk space
was one of those details.
Amiga systems stored roughly 880 KB on one double-density
floppy disk. Atari's TOS, however, stored only 720 KB by default.
Very soon, clever Atari programmers found that it was possible to
use 10 instead of 9 sectors per track, increasing the disk space
to roughly 800 KB.
Not bad, I thought, but I wasn't satisifed; the extra 80 KB
on the Amiga bothered me. And so I set out to learn the low-level
details of how both the Amiga and the Atari stored their data on
floppy disk.
I disassembled operating system code. I dug through system programming
manuals. I tried to understand floppy disk controller principles,
and the particulars of Western Digital's 1772 floppy disk controller
which was used in the Atari. My head was spinning.
Hyperformat was the result. By tuning the track parameters to the
maximum, it allowed the Atari to match the Amiga's capabilities -
880 KB on a standard DD floppy disk, and even more by using extra
tracks. (Most floppy disk drives allowed to store data even beyond
track 79, which was nominally the "last" track for DD disks.)
Hyperformat was indeed a real breakthrough. Other formatters came
after it, but it was this little piece of code, written entirely
in 68000 assembly language, which proved that it could be done.
I published an article on it in ST-Computer magazine; the article
turned into a a series on disk programming - and from the series,
the idea of a book came up: Scheibenkleister.
So basically, it was the Amiga which led me into writing a book
on Atari disk and system programming. Only one of the reasons why
I still think that the Amiga was a fine system in
many respects.
An extended version of Hyperformat
was shipped with Scheibenkleister, and later Hyperformat broke even more
records - for example, it was the first formatter which supported
overclocked FDCs and high-density disks. If you wanted to squeeze
the maximum out of your floppy disk, Hyperformat was your weapon.
- Programming information for the WD1770/1772 (funet.fi)
- Original 1772 product spec by WD (scanned images)
- Probing the FDC (Dave Small)
- Hyperformat
Revision: r1.2 - 05 Jan 2005 - 22:52 - ClausBrod