VG 93

Hello, All! The subject is unclear. In Fedin’s book it is written like this: Port #FF. The system register is used to select disk drives and perform other other auxiliary actions. Its structure: 7 6 5 4 3 2 1 0 │ │ │ │ └─┴─Disk drive number (0 - 3). │ │ │ └─────VG-93 reset, if 0. │ │ └───────Head loading. │ └─────────Disk side (0 - bottom). └─────────────Recording method (0 - FM, 1 - MFM). But in Solonov’s book, “repairing disk drives” is not at all like that. bit 2 - not used bit 3 - reset bit 4 - side bit 5 - FM/MFM bits 6 and 7 of type are free :-/ Not a word about head loading. Where is the truth? #2C and #3C rule, but still? And why in all the things I have seen in programs is the 5th bit always one? By the way, does MFM coding have practical applications? It's somewhere Is it used by anyone? What is it all about? WBR, Jason. /*e-mail: jason2000(scary dog)yandex.ru ICQ: 62235830*/ /np:/ *silence*