Progress on NEC APC

On Fri, 21 Apr 2000, Don Maslin wrote: In THIS case, due to sector size differences. But not ALWAYS. I have seen non-CP/M disks with E5 where a CP/M directory would have been. MS-DOS will give a big FAT :-) error message when trying to read CP/M (actually "Probable Non-DOS disk") because it is picky about what it expects to see in the F.A.T. Due to reserved tracks, on 8" double density, CP/M's DIRectory will fall AFTER the end of the MS-DOS directory, where the first file would otherwise be likely to be. You're right that that would almost certainly be content that would choke CP/M. But with very short files and large clusters, and with sector interleave, it is entirely possible to have CP/M looking at unused sectors. Both MS-DOS and CP/M will accept and assume "empty" when encountering a DIRectory (not the MS-DOS F.A.T.) sector of all E5. MOST MS-DOS formats fill the empty directory sectors with 00, but not all. Some use E5, some F6 with E5 every 32 bytes, ... What would CP/M-86 report for a directory sector of all 00? An MS-DOS format with a large directory could easily leave the END of the MS-DOS directory sectors where the first of the CP/M directory sectors would be. I don't often see use of USER in CP/M disks. Sometimes, but not often. I think that it is more likely that they gave Sellam blank formatted diskettes. -- Fred Cisin cisin(a)xenosoft.com XenoSoft http://www.xenosoft.com 2210 Sixth St. (510) 644-9366 Berkeley, CA 94710-2219