fdrawcmd
Hurricane Electric Internet Services
NAME
fdrawcmd - send raw commands to the floppy disk controller
SYNOPSIS
rawcmd [drive=drive] [rate=rate] [length=length]
[repeat=count] [seek=physical_track] command
[parameters...] [mode]
DESCRIPTION
fdrawcmd is used to send raw commands to the floppy disk
controller, after having selected a given drive. You must
have write permission to the selected drive.
When writing to a disk, data is read from stdin; when
reading, data is printed to stdout. Diagnostic messages,
return values from the controller, and the value of the
disk change line after the command are printed to stderr.
OPTIONS
All numbers may be given in octal (0209), decimal (137),
or hexadecimal (0x89).
drive=drive
Selects the drive. The default is drive 0
(/dev/fd0).
rate=rate
Selects the data transfer rate. Use 0 for high den-
sity disks, 1 for double density 5 1/4 disks (or 2
Mbps tapes, if the appropriate rate table is se-
lected), and 2 for double density 3 1/2 disks.
length=length
Describes the length of the transferred data for
commands reading from and writing to the disk. The
default is to continue until EOF.
repeat=count
Repeat the command count times. This only works
correctly for commands which don't do any data
transfer.
command
The name of the command to send. command may be a
spelled out name (like read or write), or a number.
A named command has already a mode, whereas for a
number the mode parameter should be described using
the appropriate option.
parameter
The parameter for the command.
mode Various flags or'ed together describing the proper-
ties of the command.
COMMANDS
The description of the various floppy commands given in
this manpage is very sketchy. For more details get the
82078 spec sheet which can be found at http://www-tech-
doc.intel.com/docs/periph/fd_contr/datasheets/. Look for
the chapter COMMAND SET/DESCRIPTIONS . Older FDCs only
support a subset of the commands described therein, but
the syntax for the commands that do exist is the same.
Commands available on all FDCs
read drivesel track head sector sizecode sect_per_track
rw_gap sizecode2
Reads length bytes of data from the disk. drivesel
is the drive selector. Bit 0 and 1 describe the
drive, and bit 2 describes the head. The remaining
parameters give the track, head (yes, again), sec-
tor, size of the sector (128 * 2 ^ sizecode), sec-
tors per track (used to switch to the second head
when the first side has been read), and size of the
read-write gap. sizecode2 should be 0xff. read
returns ST0 ST1 ST2 and track head sector sizecode
of the next sector to be read; see /usr/in-
clude/linux/fdreg.h.
write drivesel track head sector sizecode sect_per_track
rw_gap sizecode
Analogous to read.
sense drivesel
Returns the third status byte (ST3).
recalibrate drivesel
Recalibrates the drive and returns ST0 ST1.
seek drivesel track
Moves the head to track and returns ST0 ST1.
specify drivesel spec1 spec2
Specify various parameters to the drive.
format drivesel sizecode sect_per_track fmt_gap fmt_fill
Formats the track. The new sectors are filled with
fmt_fill. The header information comes from the
input, which is made up of track head sector size-
code quadruples. The sizecode parameter from the
command line is used to describe the actual size of
the sectors, and the sizecode from the input is
used to write into the header. However, the first
write to these sectors will use the header informa-
tion, and might overwrite the following sectors if
the sizecode parameter from the command line was
too small.
readid drivesel
reads the first sector header that comes and re-
turns ST0 ST1 ST2 and track head sector sizecode of
the encountered header.
Commands available on 82072 and later
dumpregs
Prints the contents of the FDCs registers, if sup-
ported.
Commands available on 82072A and later
configure conf1 conf2 conf3
Configures FIFO operation.
Commands available on 82077 and later
version
Echoes 0x90 if the FDC is more recent than 82072A,
and 0x80 otherwise
perpendicular rate
Sets the perpendicular mode. Use 0 for normal, 2
for 500Kbps perpendicular, and 3 for 1Mbps perpen-
dicular.
seek_out drivesel n
does a relative seek of n tracks towards track 0.
seek_in drivesel n
does a relative seek of n tracks towards the high
numbered track.
Commands available on 82077AA and later
lock Locks the FIFO configuration, so that it survives a
FDC software reset.
unlock Unlock the FIFO configuration
Commands available on 82078
partid echoes a byte describing the type of the FDC in the
3 high bits, and the stepping in the three low
bits.
powerdown powerconf
configures automatic power down of the FDC. The old
configuration is echoed
option iso
enables/disables ISO formats. Odd values of iso en-
able these formats, whereas even values disable
them. ISO formats don't have index headers, and
thus allow to fit slightly more data on a disk.
save prints out 16 internal registers of the FDC.
restore r1 r2 r3 ... r16
restores the 16 internal registers of the FDC.
format_n_write drivesel sizecode sect_per_track fmt_gap
fmt_fill
formats the track and writes initial data to it.
The input data is made up of a sequence of headers
(4 bytes) and data: header1 data1 header2 sector2
... headern sectorn
drivespec dspec1 dspec2 ... specn terminator
chooses rate tables for various drives. Each dspec
byte describes one drive. Bits 0 and 1 say which
drive is described. Bits 2 and 3 describe the rate
table. Only tables 0 and 2 are interesting. Both
tables only differ in the meaning og rate 1. For
table 0 (the default) rate 0 is 300 Kbps (used for
5 1/4 DD disks), whereas for table 1 it is 2 Mbps
(used for fast floppy tape drives). Bit 4 is the
precompensation table select bit. It should be set
to 0. Bit 5-7 should be zero as well. The termina-
tor byte ends the drivespec command. It is either
0xc0 or 0x80. If it is 0xc0, no result phase fol-
lows; if it is 0x80, the current data rate table
configuration for the four drives is echoed.
MODES
The mode option is only needed when you describe the com-
mand as a numerical value. Some mode names are also valid
command names. They are considered as command name if the
command name has not yet been given, and as mode name oth-
erwise. If you give a command name and an explicit mode,
both the implicit flags of the command name, and the ex-
plicit mode are or'ed together. Several modes may be or'ed
together too.
read Read data from disk using DMA.
write Write data to the disk.
intr Wait for an interrupt.
spin wait for the disk to spin up
need_seek
Seeks the drives head to the correct track (as giv-
en by the seek parameter) before sending the com-
mand.
disk Aborts the operation if no disk is in the drive.
This only works if need_seek is also chosen.
no_motor
Don't switch on the drive motor while issuing the
command
no_motor_after
Switch off the motor immediately after the command
returns.
RESET
fdrawcmd opens the device node with the NDELAY flag. This
means that the driver should not try to autodetect the
disk type (it might not be formatted), and that it should
not reset the FDC. If a reset was needed, the command sim-
ply fails. If that happens, execute floppycontrol --reset-
now 0, and try again.
FILES
/dev/fd* - Floppy devices
AUTHOR
Alain Knaff, Alain.Knaff@inrialpes.fr
SEE ALSO
superformat(1), getfdprm(1), floppycontrol(1)
Hurricane Electric Internet Services
Copyright (C) 1998
Hurricane Electric.
All Rights Reserved.