berman@ihuxm.UUCP (11/30/83)
In a recently posted article, we are advised by Apple that: >Emulating a PC is a little tougher, though, because one wants PC disks >to run on the system. Well, the PC uses the index holes on diskettes >(it's hard sectored). Apple diskettes are completely soft-sectored, >so Apple doesn't bother to install the extra hardware necessary for >hard-sectoring. This makes reading PC disks a bit tough. Come on now, things are confusing enough without such blatent misinformation! Andy Berman
elwell@cwruecmp.UUCP (Clayton Elwell) (12/01/83)
It's not misinformation. The uPD765 (or 8272, if you like intel) in the PC needs the index hole, even for soft sectoring. The Apple Disk ][ drive/controller system doesn't even have the little LED for detecting the index hole. The Apple disk controller is a masterpiece of simplicity. It manages to pack 143K on a single-density, 35 track disk (using FM encoding, for hardware buffs). It uses a special self-synchronizing bit pattern in the interrecord gaps to find the start of a sector, so it doesn't need the index hole. In true Apple style, if you don't need it, why bother? The only practical way to read both formats with the same drive is to put an Apple controller and a 765 in parallel. The QuadLink board does precisely this. The only problem is that the Apple controller likes to control the stepper motor directly, so you have to emulate it. Details and documentation available upon request.
seaburg@uiucdcs.UUCP (seaburg ) (12/03/83)
#R:ihuxm:-73300:uiucdcs:24700033:000:58 uiucdcs!seaburg Dec 2 18:30:00 1983 I thought IBM diskettes were soft-sectored. Ain't so?
preece@uicsl.UUCP (12/07/83)
#R:ihuxm:-73300:uicsl:7300013:000:360 uicsl!preece Dec 5 09:39:00 1983 Sounds like the Apple's disks are softer than the IBM's. The IBM disks, however, are and have always been commonly referred to as soft-sectored. Once again we have a computer term that means exactly what the vendor means it to mean, no more and no less. Like Apple's 'high-resolution' display. Everything is relative. scott preece ihnp4!uiucdcs!uicsl!preece