Партнёры:
Хостинг:
fdcontrol - display and modify floppy disk parameters
Commands are implemented to query the current device density settings as well as the underlying device hardware as registered with the driver, to manipulate debugging levels, and to adjust the device density settings. All the operations that manipulate the kernel settings are restricted to the superuser (by the device driver), while all inquiry requests only require read access to device
The device argument should always be given as a full path name, e.g. /dev/fd0
In order to add some descriptive text that makes the output better human readable, the flag -v can be added.
Specifying flag -F will report the device's density settings in a form that is suitable as input to the -s fmtstr option (see below). Again, together with -v some more text will be returned, including the total capacity of the density settings in kilobytes.
KB sectrac secsize ncyls speed heads flags 1721 21 2 (512) 82 500 2 MFM 1476 18 2 (512) 82 500 2 MFM 1440 18 2 (512) 80 500 2 MFM 1200 15 2 (512) 80 500 2 MFM 820 10 2 (512) 82 250 2 MFM 800 10 2 (512) 80 250 2 MFM 720 9 2 (512) 80 250 2 MFM
KB sectrac secsize ncyls speed heads flags 1200 15 2 (512) 80 500 2 MFM 1232 8 3 (1024) 77 500 2 MFM 1476 18 2 (512) 82 500 2 MFM 1440 18 2 (512) 80 500 2 MFM 1200 15 2 (512) 80 500 2 MFM 820 10 2 (512) 82 300 2 MFM 800 10 2 (512) 80 300 2 MFM 720 9 2 (512) 80 300 2 MFM 360 9 2 (512) 40 300 2 MFM,2STEP 640 8 2 (512) 80 300 2 MFM
KB sectrac secsize ncyls speed heads flags 720 9 2 (512) 80 250 2 MFM
KB sectrac secsize ncyls speed heads flags 360 9 2 (512) 40 250 2 MFM
The second form to specify a device density uses -s fmtstr to explicitly specify each parameter in detail. The argument fmtstr is a comma-separated list of values of the form:
sectrac , secsize , datalen , gap , ncyls , speed heads , f_gap , f_inter , offs2 , flags
The meaning of the parameters is:
For any missing parameter, the current value will be used, so only actual changes need to be specified. Thus to turn off a flag bit (like +mfm which is the default for all drive types), the form with a leading minus sign must explicitly be used.
$ fdcontrol /dev/fd0 1.44M
Same as above, but with verbose output. Note that the result is about the drive type as opposed to a device density so it is independent from the actual subdevice being used for device
$ fdcontrol -v /dev/fd0 /dev/fd0: 1.44M drive (3.5" high-density)
Inquiry about the density settings:
$ fdcontrol -F /dev/fd0 18,512,0xff,0x1b,80,500,2,0x6c,1,0,+mfm
The verbose flag makes this human readable:
/dev/fd0: 1440 KB media type
Format: 18,512,0xff,0x1b,80,500,2,0x6c,1,0,+mfm
Sector size: 512
Sectors/track: 18
Heads/cylinder: 2
Cylinders/disk: 80
Transfer rate: 500 kbps
Sector gap: 27
Format gap: 108
Interleave: 1
Side offset: 0
Flags <MFM>
As indicated, trailing commas in the parameter list may be omitted.
In order to access archaic 160 KB single-density (FM encoded) 5.25 media in a modern 1.2M drive, something like the following definition would be needed. (Note that not all controller hardware is actually capable of handling FM encoding at all.)
# fdcontrol -s 16,128,0x80,0x2,40,300,,0x10,,,-mfm,+2step /dev/fd1.1
It is still possible to hook up 8" drives to most modern floppy controllers, given the right cable magic. (On PC hardware, tell the BIOS that it is a 5.25" drive.) The classical 128/26/2/77 format can be read with this entry
fdcontrol -s 26,128,0x80,0x2,77,500,2,0x10,,,-mfm /dev/fd0
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