Path: utzoo!attcan!uunet!ginosko!xanth!ames!attctc!wnp From: wnp@attctc.DALLAS.TX.US (Wolf Paul) Newsgroups: comp.unix.microport Subject: Re: screwy format message Keywords: software, 386/3.0e Message-ID: <8593@attctc.DALLAS.TX.US> Date: 9 Jul 89 12:52:54 GMT References: <1003@hawkmoon.MN.ORG> <8249@saturn.ucsc.edu> <1029@hawkmoon.MN.ORG> Reply-To: wnp@attctc.Dallas.TX.US (Wolf Paul) Organization: The Unix(R) Connection BBS, Dallas, Tx Lines: 66 In article <1029@hawkmoon.MN.ORG> det@hawkmoon.MN.ORG (Derek E. Terveer) writes: >> There is a coding scheme >> built into the minor device number of the file (device node) that was opened >> and in it contains info such as hi/low density, etc. My guess is that you've >> got some way bogus minor device number for f13ht or a corrupted binary. >Ok -- that begs the question: "what are the correct minor device numbers for >3.5" floppies?" This is what i currently have: > ... >Also, what do each of the bits in the minor device numbers mean? There doesn't >seem to be any documentation for these things. I have sort of made some >guesses but, these guesses are probably wrong. See below. This table was originally posted by Mark Zenier about a year ago, and I confirmed/modified it in conversation with John Plocher who was then Microport's Customer Service Manager. >When i *do* format a 3.5" disk, >it reports that 80 (0..79) tracks have been formatted; the same as for 5.25" >disks, so it must not have the correct minor device number. That does not follow; both 720K and 1.44M 3.5" disks ARE INDEED formatted as 80 tracks -- 720K disks with 9 sectors/track, 1.44M disks with 18 sectors/track. The message from format would properly be the same. Here is the table for minor number coding: 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | +-- if set, drive has 9 sectors/track | | | | | | +---- if set, drive is double-sided | | | | | +------ if set, drive has 80 cylinders | | | | +-------- Drive number ( 0 or 1 ) | | | +---------- if NOT set, drive is high density (1.2 or 1.44) | | +------------ if set, drive is 3.5" | +-------------- if NOT set, read 40-cyl disk on 80-cyl drive (double-step) +---------------- if set, skip cylinder #0 (INSTALL floppies, 0s25) From this then, result the following minor numbers: For Drive 0: Standard AT 1.2M : 01000110 70 (fd096ds15, 0s24) Standard XT 360K : 00010111 23 (fd048ds9) Old XT 320K : 00010110 22 (fd048ds8) Old XT 160 : 00010100 20 (fd048ss8) Quad Density 720K 5.25" : 01010111 87 (fd096ds9) Double Density 720K 3.5" : 01110111 119 (fd0mf2dd) High Density 1.4M 3.5" : 01100110 102 (fd0mf2hd) And for Drive 1: (Add 1000 binary, or 8 decimal to the numbers for Drive 0) Standard AT 1.2M : 01001110 78 (fd096ds15, 0s24) Standard XT 360K : 00011111 31 (fd048ds9) Old XT 320K : 00011110 30 (fd048ds8) Old XT 160 : 00011100 28 (fd048ss8) Quad Density 720K 5.25" : 01011111 95 (fd096ds9) Double Density 720K 3.5" : 01111111 127 (fd0mf2dd) High Density 1.4M 3.5" : 01101110 110 (fd0mf2hd) I have used these minor numbers successfully on my Uport 286 system until I sold it late last year. -- Wolf N. Paul * 3387 Sam Rayburn Run * Carrollton TX 75007 * (214) 306-9101 UUCP: {texbell, attctc, dalsqnt}!dcs!wnp DOMAIN: wnp@attctc.dallas.tx.us or wnp%dcs@texbell.swbt.com NOTICE: As of July 3, 1989, "killer" has become "attctc".