mirror of https://github.com/mkerrisk/man-pages
233 lines
7.4 KiB
Groff
233 lines
7.4 KiB
Groff
.\" Copyright (c) 1993 Michael Haardt (michael@cantor.informatik.rwth-aachen.de)
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.\" and 1994,1995 Alain Knaff (Alain.Knaff@imag.fr)
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.\"
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.\" %%%LICENSE_START(GPLv2+_DOC_FULL)
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.\" This is free documentation; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License as
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.\" published by the Free Software Foundation; either version 2 of
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.\" the License, or (at your option) any later version.
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.\"
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.\" The GNU General Public License's references to "object code"
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.\" and "executables" are to be interpreted as the output of any
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.\" document formatting or typesetting system, including
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.\" intermediate and printed output.
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.\"
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.\" This manual is distributed in the hope that it will be useful,
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.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
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.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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.\" GNU General Public License for more details.
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.\"
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.\" You should have received a copy of the GNU General Public
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.\" License along with this manual; if not, see
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.\" <http://www.gnu.org/licenses/>.
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.\" %%%LICENSE_END
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.\"
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.\" Modified, Sun Feb 26 15:00:02 1995, faith@cs.unc.edu
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.\"
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.TH FD 4 2020-08-13 "Linux" "Linux Programmer's Manual"
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.SH NAME
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fd \- floppy disk device
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.SH CONFIGURATION
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Floppy drives are block devices with major number 2.
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Typically they
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are owned by
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root:floppy
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(i.e., user root, group floppy) and have
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either mode 0660 (access checking via group membership) or mode 0666
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(everybody has access).
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The minor
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numbers encode the device type, drive number, and controller number.
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For each device type (that is, combination of density and track count)
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there is a base minor number.
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To this base number, add the drive's
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number on its controller and 128 if the drive is on the secondary
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controller.
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In the following device tables, \fIn\fP represents the
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drive number.
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.PP
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\fBWarning: if you use formats with more tracks
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than supported by your drive, you may cause it mechanical damage.\fP
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Trying once if more tracks than the usual 40/80 are supported should not
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damage it, but no warranty is given for that.
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If you are not sure, don't create device
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entries for those formats, so as to prevent their usage.
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.PP
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Drive-independent device files which automatically detect the media
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format and capacity:
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.TS
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l c
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l c.
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Name Base
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minor #
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_
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\fBfd\fP\fIn\fP 0
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.TE
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.PP
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5.25 inch double-density device files:
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.TS
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lw(1i) l l l l c
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lw(1i) c c c c c.
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Name Capacity Cyl. Sect. Heads Base
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KiB minor #
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_
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\fBfd\fP\fIn\fP\fBd360\fP 360 40 9 2 4
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.TE
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.PP
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5.25 inch high-density device files:
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.TS
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lw(1i) l l l l c
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lw(1i) c c c c c.
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Name Capacity Cyl. Sect. Heads Base
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KiB minor #
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_
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\fBfd\fP\fIn\fP\fBh360\fP 360 40 9 2 20
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\fBfd\fP\fIn\fP\fBh410\fP 410 41 10 2 48
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\fBfd\fP\fIn\fP\fBh420\fP 420 42 10 2 64
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\fBfd\fP\fIn\fP\fBh720\fP 720 80 9 2 24
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\fBfd\fP\fIn\fP\fBh880\fP 880 80 11 2 80
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\fBfd\fP\fIn\fP\fBh1200\fP 1200 80 15 2 8
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\fBfd\fP\fIn\fP\fBh1440\fP 1440 80 18 2 40
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\fBfd\fP\fIn\fP\fBh1476\fP 1476 82 18 2 56
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\fBfd\fP\fIn\fP\fBh1494\fP 1494 83 18 2 72
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\fBfd\fP\fIn\fP\fBh1600\fP 1600 80 20 2 92
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.TE
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.PP
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3.5 inch double-density device files:
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.TS
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lw(1i) l l l l c
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lw(1i) c c c c c.
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Name Capacity Cyl. Sect. Heads Base
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KiB minor #
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_
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\fBfd\fP\fIn\fP\fBu360\fP 360 80 9 1 12
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\fBfd\fP\fIn\fP\fBu720\fP 720 80 9 2 16
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\fBfd\fP\fIn\fP\fBu800\fP 800 80 10 2 120
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\fBfd\fP\fIn\fP\fBu1040\fP 1040 80 13 2 84
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\fBfd\fP\fIn\fP\fBu1120\fP 1120 80 14 2 88
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.TE
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.PP
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3.5 inch high-density device files:
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.TS
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lw(1i) l l l l c
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lw(1i) c c c c c.
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Name Capacity Cyl. Sect. Heads Base
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KiB minor #
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_
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\fBfd\fP\fIn\fP\fBu360\fP 360 40 9 2 12
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\fBfd\fP\fIn\fP\fBu720\fP 720 80 9 2 16
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\fBfd\fP\fIn\fP\fBu820\fP 820 82 10 2 52
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\fBfd\fP\fIn\fP\fBu830\fP 830 83 10 2 68
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\fBfd\fP\fIn\fP\fBu1440\fP 1440 80 18 2 28
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\fBfd\fP\fIn\fP\fBu1600\fP 1600 80 20 2 124
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\fBfd\fP\fIn\fP\fBu1680\fP 1680 80 21 2 44
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\fBfd\fP\fIn\fP\fBu1722\fP 1722 82 21 2 60
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\fBfd\fP\fIn\fP\fBu1743\fP 1743 83 21 2 76
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\fBfd\fP\fIn\fP\fBu1760\fP 1760 80 22 2 96
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\fBfd\fP\fIn\fP\fBu1840\fP 1840 80 23 2 116
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\fBfd\fP\fIn\fP\fBu1920\fP 1920 80 24 2 100
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.TE
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.PP
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3.5 inch extra-density device files:
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.TS
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lw(1i) l l l l c
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lw(1i) c c c c c.
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Name Capacity Cyl. Sect. Heads Base
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KiB minor #
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_
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\fBfd\fP\fIn\fP\fBu2880\fP 2880 80 36 2 32
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\fBfd\fP\fIn\fP\fBCompaQ\fP 2880 80 36 2 36
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\fBfd\fP\fIn\fP\fBu3200\fP 3200 80 40 2 104
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\fBfd\fP\fIn\fP\fBu3520\fP 3520 80 44 2 108
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\fBfd\fP\fIn\fP\fBu3840\fP 3840 80 48 2 112
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.TE
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.SH DESCRIPTION
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\fBfd\fP special files access the floppy disk drives in raw mode.
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The following
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.BR ioctl (2)
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calls are supported by \fBfd\fP devices:
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.IP \fBFDCLRPRM\fP
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clears the media information of a drive (geometry of disk in drive).
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.IP \fBFDSETPRM\fP
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sets the media information of a drive.
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The media information will be
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lost when the media is changed.
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.IP \fBFDDEFPRM\fP
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sets the media information of a drive (geometry of disk in drive).
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The media information will not be lost when the media is changed.
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This will disable autodetection.
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In order to reenable autodetection, you
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have to issue an \fBFDCLRPRM\fP.
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.IP \fBFDGETDRVTYP\fP
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returns the type of a drive (name parameter).
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For formats which work
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in several drive types, \fBFDGETDRVTYP\fP returns a name which is
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appropriate for the oldest drive type which supports this format.
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.IP \fBFDFLUSH\fP
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invalidates the buffer cache for the given drive.
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.IP \fBFDSETMAXERRS\fP
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sets the error thresholds for reporting errors, aborting the operation,
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recalibrating, resetting, and reading sector by sector.
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.IP \fBFDSETMAXERRS\fP
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gets the current error thresholds.
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.IP \fBFDGETDRVTYP\fP
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gets the internal name of the drive.
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.IP \fBFDWERRORCLR\fP
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clears the write error statistics.
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.IP \fBFDWERRORGET\fP
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reads the write error statistics.
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These include the total number of
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write errors, the location and disk of the first write error, and the
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location and disk of the last write error.
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Disks are identified by a
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generation number which is incremented at (almost) each disk change.
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.IP \fBFDTWADDLE\fP
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Switch the drive motor off for a few microseconds.
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This might be
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needed in order to access a disk whose sectors are too close together.
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.IP \fBFDSETDRVPRM\fP
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sets various drive parameters.
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.IP \fBFDGETDRVPRM\fP
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reads these parameters back.
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.IP \fBFDGETDRVSTAT\fP
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gets the cached drive state (disk changed, write protected et al.)
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.IP \fBFDPOLLDRVSTAT\fP
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polls the drive and return its state.
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.IP \fBFDGETFDCSTAT\fP
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gets the floppy controller state.
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.IP \fBFDRESET\fP
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resets the floppy controller under certain conditions.
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.IP \fBFDRAWCMD\fP
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sends a raw command to the floppy controller.
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.PP
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For more precise information, consult also the \fI<linux/fd.h>\fP and
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\fI<linux/fdreg.h>\fP include files, as well as the
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.BR floppycontrol (1)
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manual page.
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.SH FILES
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.I /dev/fd*
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.SH NOTES
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The various formats permit reading and writing many types of disks.
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However, if a floppy is formatted with an inter-sector gap that is too small,
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performance may drop,
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to the point of needing a few seconds to access an entire track.
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To prevent this, use interleaved formats.
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.PP
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It is not possible to
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read floppies which are formatted using GCR (group code recording),
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which is used by Apple II and Macintosh computers (800k disks).
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.PP
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Reading floppies which are hard sectored (one hole per sector, with
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the index hole being a little skewed) is not supported.
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This used to be common with older 8-inch floppies.
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.\" .SH AUTHORS
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.\" Alain Knaff (Alain.Knaff@imag.fr), David Niemi
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.\" (niemidc@clark.net), Bill Broadhurst (bbroad@netcom.com).
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.SH SEE ALSO
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.BR chown (1),
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.BR floppycontrol (1),
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.BR getfdprm (1),
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.BR mknod (1),
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.BR superformat (1),
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.BR mount (8),
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.BR setfdprm (8)
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