4 ms·

Interesting - I should really try to find the specifics on how AmigaOS stored its data. I'm guessing it's not MFM as the optional driver slash virtual device fo

by krige 5y ago

Interesting - I should really try to find the specifics on how AmigaOS stored its data. I'm guessing it's not MFM as the optional driver slash virtual device for reading IBM floppies required an MFM driver (thus implying MFM is not in use for standard AOS floppies). [edit] it actually IS mfm after all https://wiki.amigaos.net/wiki/Amiga_Floppy_Boot_Process_and_Physical_Layout https://wiki.amigaos.net/wiki/Amiga_Floppy_Boot_Process_and_...

hilbert42 5y ago
FYI, the MFM/Modified Frequency Modulation is also described in the original Shugart SA800/SA801 8-inch floppy diskette drives manuals. The OEM Manual describes the basic MFM information and the Maintenance Manual contains the PCB layouts, logic information and the schematic diagrams. The first two links are to the OEM/Theory of Operation Manual and the third link is to the Maintenance Manual. https://hxc2001.com/download/datasheet/floppy/thirdparty/Shugart_Associates/50664-0_SA800_801_Theory_of_Operations_Apr76.pdf https://hxc2001.com/download/datasheet/floppy/thirdparty/Shu... http://avitech.com.au/mm-files/dilog-dq419/SA800-801_Diskette_Drive_OEM_Manual_1977_Shugart.pdf http://avitech.com.au/mm-files/dilog-dq419/SA800-801_Diskett... http://bitsavers.informatik.uni-stuttgart.de/www.computer.museum.uq.edu.au/pdf/SA800&801%20Diskette%20Storage%20Drive%20Maintenance%20Manual.pdf http://bitsavers.informatik.uni-stuttgart.de/www.computer.mu... BTW, I still have two SA800 drives from my old CompuPro 8/16 S-100 system that I thought would be nice to play with again when I had a moment but I've no 8" floppies either single or double density. Does anyone know where one can get some?
bcrl 5y ago
The Amiga floppy controller hardware just DMAs the bits to / from RAM. MFM encoding and decoding is implemented in the software trackdisk.device by using the blitter.

by krige 5y ago

hilbert42 5y ago

FYI, the MFM/Modified Frequency Modulation is also described in the original Shugart SA800/SA801 8-inch floppy diskette drives manuals. The OEM Manual describes the basic MFM information and the Maintenance Manual contains the PCB layouts, logic information and the schematic diagrams. The first two links are to the OEM/Theory of Operation Manual and the third link is to the Maintenance Manual. https://hxc2001.com/download/datasheet/floppy/thirdparty/Shugart_Associates/50664-0_SA800_801_Theory_of_Operations_Apr76.pdf https://hxc2001.com/download/datasheet/floppy/thirdparty/Shu... http://avitech.com.au/mm-files/dilog-dq419/SA800-801_Diskette_Drive_OEM_Manual_1977_Shugart.pdf http://avitech.com.au/mm-files/dilog-dq419/SA800-801_Diskett... http://bitsavers.informatik.uni-stuttgart.de/www.computer.museum.uq.edu.au/pdf/SA800&801%20Diskette%20Storage%20Drive%20Maintenance%20Manual.pdf http://bitsavers.informatik.uni-stuttgart.de/www.computer.mu... BTW, I still have two SA800 drives from my old CompuPro 8/16 S-100 system that I thought would be nice to play with again when I had a moment but I've no 8" floppies either single or double density. Does anyone know where one can get some?

bcrl 5y ago

The Amiga floppy controller hardware just DMAs the bits to / from RAM. MFM encoding and decoding is implemented in the software trackdisk.device by using the blitter.