Evenin' all... I've found a slight problem with Prodos (including Johnathan's version) and external drives...
Basically, the seek command in Prodos doesn't hold the correct value -- it disables the spin-up sequence. To get it to work, you should poke the bit which does: LD A,31 OUT (C),A with LD A,%10111 .... Hope that helps -- it got Prodos working nicely on our system anyway Si
