PC-DOS and PC Compatible MS-DOS floppy formats (Was: "Smartcom II" package available

On Thu, 18 Sep 2014, steve shumaker wrote: OK, to get you started: These are PC-DOS and PC compatible MS-DOS systems. NON-PC-compatible MS-DOS machines often did many things differently (see Victor 9000) MS-DOS and PC-DOS 1.00 used 5.25" MFM, 8 sectors per track, single sided (aka "160K") Note: there were some patches for using DS drives with DOS 1.00, treating the second side of each disk as an additional drive! MS-DOS 1.25 and PC-DOS 1.10 added double sided. ("160K", "320K") MS-DOS,PC-DOS 2.00 added 9 SPT ("160K", "320K", "180K", 360K") PC-DOS 2.10 added no new formats, but slowed down the drive access to work with the Qume142 drives. MS-DOS 2.11 (THERE WAS NO PC-DOS 2.11) was readily customized by OEMs. Some added 80 track SS and/or DS drives, including 3.5" (such as Gavilan) Many/most of the 2.11 3.5" formats were NOT the same as PC-DOS 3.5" "720K", which came with PC-DOS 3.20 MS-DOS,PC-DOS 3.00 added "1.2M". Note that that is VERY much like an 8"DSDD format. NEC people (MS-DOS not PC compatible) can now giggle joyfully. MS-DOS,PC-DOS 3.10 added the [undocumented?] "network redirector", which among other things, let MSCDEX take a large drive, such as a CD-ROM (~660M) and present it to the computer as if it were a remote device on a network. MS-DOS,PC-DOS 3.20 provided officially sanctioned 3.5" "720K" Systems with 5.25" 80 track NOT-HD drives sometimes conflated them with 3.5" "720K" (see IBM PC/JX) Both had DRIVER.SYS for such drives. (particularly on machines whose CMOS did not have "720K") Both had DRIVPARM, documented in MS-DOS, undocumented in PC-DOS. However, DRIVPARM (MS-DOS OR PC-DOS) would work with most after market BIOS, but would FAIL with real OEM IBM PC/AT BIOS! MS-DOS,PC-DOS 3.30 added support for "1.4M" MS-DOS 3.31 was the next heavily customized version. There was no PC-DOS 3.31. 3.31 also broke the 32M hard drive limit. MS-DOS,PC-DOS 4.00 continued the "large" drive support, but was not completely compatible with Norton fUtilities, which created a flood of "bug reports". 4.01 fixed some bugs, and was also compatible with the new version of Norton fUtilities (re-written to work with "large" drive support) Some versions of 4.01 had a minor bug of misreporting version number as 4.00 MS-DOS 5.00 was the first RETAIl/NOT-OEM version of MS-DOS. Any versions of MS-DOS prior to that were only allowed to be sold with a PC, although there are some reports that there were [millions of] gray-market copies in existence! MS-DOS 6.00 and PC-DOS 6.10 each came bundled (DIFFERENT bundles!) with disk compression, backup programs, etc. It installed an agressive configuration of SMARTDRV that caused most of the press and ignorant users to blame "disk compression" for many problems with data loss. MS-DOS 6.20 was updated to solve the "disk compression caused data losses". It did that ENTIRELY by reining in SMARTDRV. MS-DOS 6.21 was due to Microsoft losing an infringement lawsuit to STAC Electronics over their disk compression software. It was the same as 6.20 with no disk compression. MS-DOS 6.22 was the same as 6.20 and 6.21 with non-infringing disk compression. I don't remember which version of DOS introduced the "2.8M" format. -- Grumpy Ol' Fred cisin at xenosoft.com