This is my own little contribution to the world of formatting hard discs, a Winchester verifier.
It uses the Adaptec Mode Sense command to read the disc's parameters, then it uses the Read Capacity command to read the size of the disc, and by subtracting the total sectors on the disc by the capacity of the disc, it works out how many bad sectors there are.
It then performs a verify, operating on a block of sectors at once. The Adaptec Verify command has two bytes for the number of sectors to be verified, so that's up to 65,536 sectors. The trouble with this is that the Beeb is lost to the disc controller whilst this is going on, so we don't get a very instructive display of progress on screen. So (unlike Superform) I get it to verify about 4,096 sectors at a time.