I've managed to get my grubby paws on a Seagate ST22R RLL controller,
and a matching ST-277R-1 hard drive (half-height 5.25in, 60MB ish). As
part of my "pre-installation research", I Googled the part number of the
one apparently-non-Seagate-custom part on the ST22R -- an Adaptec
AIC-010 RLL controller. Turns out the datasheet for this part is on
The datasheet provides a decent overview of the on-disc format
(specifically: it's a tweaked variant of the IBM floppy disc low-level
format, sitting on top of (2,7)RLL). What it doesn't really cover is the
32-bit error-correction code and its polynomial. There is a slightly
oblique reference to Fire codes, there are two polynomials (forward and
reverse), and data is loaded in shift-register style.
Does anyone know what sort of error-correction codes were used on the
AIC-010 and AIC-100 controller chips, or the polynomials used?
classiccmp at philpem.me.uk