2.5" hds maded by IBM (brand can vary: IBM, Toshiba or even Apple, they are all the same) works great in A600/1200!
Last week I tried a 6.5 Gb IBM hd on my dusty A600 (ks 37300!) and hdtoolbox (2.1!) recognises it in the 1st try!
And I never got a single problem with those winchesters! :quickdraw: