Le vendredi 07 juin 2013, Gene Heskett a écrit :
On Friday 07 June 2013 09:04:36 Martin Gregorie did opine:
Some time back my 68000-based OS/9 system died and I needed to get stuff off the 3.5" floppies I use to back it up.
I'm a Linux user, so I used setfdprm to fiddle with the parameters in the 'floppy' driver and was able to image the disks successfully and then use the os9exec OS/9 emulator to access their contents.
The reason I'm mentioning this is that I used a standard Linux driver, which normally uses 512b blocks and a standard 3.5" drive to read OS/9 floppies while the parameters needed to read the OS/9 floppies were:
hd sect=34 ssize=256 head=2 cyl=80 tracksize=8704 dtr=0 zerobased
I haven't yet tried it on any Flex-09 disks: mine all use single density for track zero and deduce the format of the other tracks from its contents. I wrote the drivers and may have diddled with the formatter when I replaced the original two disk FD card with a Windrush card that that handles 4 drives off a pair of FDC chips.
I'm posting this to say thanks for writing such a good "get out of jail free" utility and as an indication to any other Linux users of just what setfdprm is capable of.
Martin
I don't want to rain on this parade, but there are FDC's on some motherboards that flat will not access disks other than 512 byte/sector.
The board in this box is one such. Doing a setfdparm to the 256 byte format that the 6809 os9 machines use, and then sending dd to either read or write a disk image will churn and hammer the drive for several retry cycles, then apparently tosses the dice to see if it locks this quad core phenom up, requiring a hardware reset or returns an error. If a write was attempted, I can take the disk to a real os9 system and inspect it with dEd, and it has not been touched. This is an ASUS M2N-SLI Deluxe board I paid nearly 300 USD for, not too long after the phenoms came out.
The moral I guess is that if you need to access 256 byte per sector disks, make sure the FDC on the board you are buying will indeed work before dropping the card for it.
Cheers, Gene
------------------------------------ Hi Gene,
It worked ”well enougth” for me. I used such commands:
fdrawcmd drive=/dev/fd0 readid 0 rate=0 need_seek track=0 espectigng a restore command, and for most of the work: fdrawcmd read 0 0 0 3 1 52 0x1b 0xff length=256 Could it be working because of the length parameter, the 256 remaining bytes being silently ignored?
I tryed first to read full track by full track (26 sectors x 256 bytes each, two sides by cylinder), but unsuccessfully. That's why I thought to such a "256 remaining bytes being silently ignored" reason.
I wrote ”well enougth” because I have problems with 3 or 4 of the 16 disks. A side, allways the same, seems to randomly miss sectors. I wonder if a head of the driver would not be durty or near its end of life. Could it be a Media problem, that would result in too low level signals? I configured the drive, in the BIOS, as a 1.2M, 5.25" floppy: could matter? The medias are marked "double sided, high density, 96 TPI/1.6 M.B. Sect: soft". Who could tell me how many types of media (the magnetic coating point of view) existed for the 5.25" floppy (but the "soft" sector case, then).
Cheers, Patrick
Excuse, pleas my poor english writing.