Reading various format 5.25" floppies on a PC

--- "Fred Cisin (XenoSoft)" &lt;cisin(a)xenosoft.com&gt; wrote: Indeed - and it cuts both ways ;-) Those are two different skills. Soldering surface mount is a matter of vision, manual dexterity and practice. The correct tools help, but I can prove that you can do a lot with just a temp-controlled iron and a steady hand. Modifying the Mac disk controller is an entirely different kettle of fish - like the Amiga, unlike old ISA PCs, it's a custom affair. The oldest Macs use the "IWM" chip the Integrated Woz Machine. Single- sided Mac drives varied the drive speed to achieve several recording densities; later ones varied the bit clock under software control (similar to what the Commodore 2040/3040/1541/2031/etc. drives did). Between that and GCR vs MFM, there are major obstacles for getting different platforms to read each other's disks. The one that is the most universal is the Amiga - it uses part of the sound chip for a 4096-bit shift register to clock an entire track in or out. The hardware handles flux reversals - the *software* cobbles up the MFM formatting, intersector gap, headers, data and all. In practice, the graphics chips perform the binary<->MFM translation, but that's just because it can - it's doable purely in software, albeit more slowly. The biggest problem with Amiga FDC design is that it's limited to DD data rates - its high-density floppies spin at 50% and are somewhat scarce (AFAIK, the drive itself senses the HD hole and spins the disc at the right rate; it's not a software thing). Unless you start from scratch, I doubt there's any one platform that has a chance of reading "all" floppy formats - that's why they made the Catweasel. It's a shame that the software never lived up to the promise of the hardware. -ethan