wrp@biochsn.acc.Virginia.EDU (William R. Pearson) (10/12/89)
I have just installed a high density 3.5" floppy on my genuine vintage IBM-PC/AT (with Inboard 386). I told the CMOS rom that I had two high density drives, and DOS 3.31 works just fine. Unfortunately, Xenix cannot read dos disks with dosdir /dev/fd196ds18, or any other combination of things that I have tried. When Xenix boots, it says it thinks that the floppy #2 is a /fd196ds15 drive, which is what it is being told by the CMOS RAM. How do I tell it otherwise? I have Xenix 2.3.2 for the 386. Bill Pearson
bblue@toshi.cts.com (Bill Blue) (10/13/89)
In article <2095@hudson.acc.virginia.edu> wrp@biochsn (William R. Pearson) writes: > Unfortunately, Xenix cannot read dos disks with dosdir /dev/fd196ds18, >or any other combination of things that I have tried. When Xenix boots, >it says it thinks that the floppy #2 is a /fd196ds15 drive, which is >what it is being told by the CMOS RAM. How do I tell it otherwise? >I have Xenix 2.3.2 for the 386. A 3.5" standard density (720k) should use /dev/fd[01]135ds9 and the 3.5" high density (1.44mb) should use /dev/fd[01]135ds18. Further, the bios has to be set to the appropriate drive type. I.e., you can't have the bios set for a 1.2mb floppy and expect Xenix to deal with them as 1.44mb correctly. Xenix will, however, talk correctly to a 720k 3.5" even if the bios is set at 1.2mb 5.25" floppy -- At least on the two different machines I've tried it on here. GEAR CHANGE Which brings me to another question. Can anyone tell me why, in the mkdev fd script (/usr/lib/mkdev/fd), there is no support for 1.44mb 3.5" disks? Now, I've modified my fd script to include all drive types and sizes, and allowed it to produce a 1.44mb boot/root 3.5" floppy (modifications available for the asking). But for the life of me I can't figure out why this seemingly obvious option would have been left out. rosso? Anyone? It seems to work just fine... --Bill
aryeh@eddie.mit.edu (Aryeh M. Weiss) (10/18/89)
In article <7@toshi.cts.com> bblue@toshi.cts.com (Bill Blue) writes: >In article <2095@hudson.acc.virginia.edu> wrp@biochsn (William R. Pearson) writes: >> Unfortunately, Xenix cannot read dos disks with dosdir /dev/fd196ds18, >>or any other combination of things that I have tried. When Xenix boots, >>it says it thinks that the floppy #2 is a /fd196ds15 drive, which is >>what it is being told by the CMOS RAM. How do I tell it otherwise? >>I have Xenix 2.3.2 for the 386. > >A 3.5" standard density (720k) should use /dev/fd[01]135ds9 and the >3.5" high density (1.44mb) should use /dev/fd[01]135ds18. Further, >the bios has to be set to the appropriate drive type. I.e., you can't >have the bios set for a 1.2mb floppy and expect Xenix to deal with >them as 1.44mb correctly. Xenix will, however, talk correctly to a >720k 3.5" even if the bios is set at 1.2mb 5.25" floppy -- At least ^^^^ Huh? Bios? Xenix does not deal with the bios, you mean the cmos ram. I bought a 3.5" floppy and had the same problem. The setup program for the computer only knew about 720KB 3.5" disks. The key is to set the cmos configuration byte for the floppies, as Mr. Pearson surmised above. This can be done via the /etc/cmos program. Byte 0x10 in the cmos is the floppy configuration byte. The upper nibble (4 bits) of the byte is for the 1st drive and the low order nibble is the second drive. The nibble values are: 0 = no drive installed 1 = low density 5.25" 2 = high density 5.25" (1.2MB) 3 = low density 3.5" (720 KB) 4 = high density 3.5" (1.44 MB) Example: if, like me, drive one is a 1.2MB drive and drive two is 1.44MB then your configuration byte should be 0x24. To set this byte run /etc/cmos 0x10 0x24 Reboot and Xenix should report the two drives as 96ds15 and 135ds18 respectively. Enjoy. -- eliot%lees-rif@eddie.mit.edu