Ah yes, I remember what I spent most of Sunday doing now . . .

Owing to the injured knee, I spent most of today salvaging bits of computer hardware to make into a single, working PC. So now I have a Intel-based 486DX, with two hard-drives (totalling less that 1.5GB), lying on my bed, not quite working. I turn the power on, the boot-up sequence completes the L, I and L of LILO but when it gets to O, I just get a minus sign:

LIL-

I know what this means:

The descriptor table is corrupt. This can either be caused by a geometry mismatch or by moving /boot/map without running the map installer. Invalid map file data or /boot/boot.b has been moved without reinstalling LILO or a disk error has occurred.

. . . but not how to fix it.