man4/fd.4

   1 .\" Copyright (c) 1993 Michael Haardt (michael@cantor.informatik.rwth-aachen.de)
   2 .\" and 1994,1995 Alain Knaff (Alain.Knaff@imag.fr)
   3 .\"
   4 .\" SPDX-License-Identifier: GPL-2.0-or-later
   5 .\"
   6 .\" Modified, Sun Feb 26 15:00:02 1995, faith@cs.unc.edu
   7 .\"
   8 .TH FD 4 (date) "Linux man-pages (unreleased)"
   9 .SH NAME
  10 fd \- floppy disk device
  11 .SH CONFIGURATION
  12 Floppy drives are block devices with major number 2.
  13 Typically they
  14 are owned by
  15 root:floppy
  16 (i.e., user root, group floppy) and have
  17 either mode 0660 (access checking via group membership) or mode 0666
  18 (everybody has access).
  19 The minor
  20 numbers encode the device type, drive number, and controller number.
  21 For each device type (that is, combination of density and track count)
  22 there is a base minor number.
  23 To this base number, add the drive's
  24 number on its controller and 128 if the drive is on the secondary
  25 controller.
  26 In the following device tables, \fIn\fP represents the
  27 drive number.
  28 .PP
  29 \fBWarning: if you use formats with more tracks
  30 than supported by your drive, you may cause it mechanical damage.\fP
  31 Trying once if more tracks than the usual 40/80 are supported should not
  32 damage it, but no warranty is given for that.
  33 If you are not sure, don't create device
  34 entries for those formats, so as to prevent their usage.
  35 .PP
  36 Drive-independent device files which automatically detect the media
  37 format and capacity:
  38 .TS
  39 l c
  40 l c.
  41 Name    Base
  42         minor #
  43 _
  44 \fBfd\fP\fIn\fP 0
  45 .TE
  46 .PP
  47 5.25 inch double-density device files:
  48 .TS
  49 lw(1i) l l l l c
  50 lw(1i) c c c c c.
  51 Name    Capacity        Cyl.    Sect.   Heads   Base
  52         KiB                             minor #
  53 _
  54 \fBfd\fP\fIn\fP\fBd360\fP       360     40      9       2       4
  55 .TE
  56 .PP
  57 5.25 inch high-density device files:
  58 .TS
  59 lw(1i) l l l l c
  60 lw(1i) c c c c c.
  61 Name    Capacity        Cyl.    Sect.   Heads   Base
  62         KiB                             minor #
  63 _
  64 \fBfd\fP\fIn\fP\fBh360\fP       360     40      9       2       20
  65 \fBfd\fP\fIn\fP\fBh410\fP       410     41      10      2       48
  66 \fBfd\fP\fIn\fP\fBh420\fP       420     42      10      2       64
  67 \fBfd\fP\fIn\fP\fBh720\fP       720     80      9       2       24
  68 \fBfd\fP\fIn\fP\fBh880\fP       880     80      11      2       80
  69 \fBfd\fP\fIn\fP\fBh1200\fP      1200    80      15      2       8
  70 \fBfd\fP\fIn\fP\fBh1440\fP      1440    80      18      2       40
  71 \fBfd\fP\fIn\fP\fBh1476\fP      1476    82      18      2       56
  72 \fBfd\fP\fIn\fP\fBh1494\fP      1494    83      18      2       72
  73 \fBfd\fP\fIn\fP\fBh1600\fP      1600    80      20      2       92
  74 .TE
  75 .PP
  76 3.5 inch double-density device files:
  77 .TS
  78 lw(1i) l l l l c
  79 lw(1i) c c c c c.
  80 Name    Capacity        Cyl.    Sect.   Heads   Base
  81         KiB                             minor #
  82 _
  83 \fBfd\fP\fIn\fP\fBu360\fP       360     80      9       1       12
  84 \fBfd\fP\fIn\fP\fBu720\fP       720     80      9       2       16
  85 \fBfd\fP\fIn\fP\fBu800\fP       800     80      10      2       120
  86 \fBfd\fP\fIn\fP\fBu1040\fP      1040    80      13      2       84
  87 \fBfd\fP\fIn\fP\fBu1120\fP      1120    80      14      2       88
  88 .TE
  89 .PP
  90 3.5 inch high-density device files:
  91 .TS
  92 lw(1i) l l l l c
  93 lw(1i) c c c c c.
  94 Name    Capacity        Cyl.    Sect.   Heads   Base
  95         KiB                             minor #
  96 _
  97 \fBfd\fP\fIn\fP\fBu360\fP       360     40      9       2       12
  98 \fBfd\fP\fIn\fP\fBu720\fP       720     80      9       2       16
  99 \fBfd\fP\fIn\fP\fBu820\fP       820     82      10      2       52
 100 \fBfd\fP\fIn\fP\fBu830\fP       830     83      10      2       68
 101 \fBfd\fP\fIn\fP\fBu1440\fP      1440    80      18      2       28
 102 \fBfd\fP\fIn\fP\fBu1600\fP      1600    80      20      2       124
 103 \fBfd\fP\fIn\fP\fBu1680\fP      1680    80      21      2       44
 104 \fBfd\fP\fIn\fP\fBu1722\fP      1722    82      21      2       60
 105 \fBfd\fP\fIn\fP\fBu1743\fP      1743    83      21      2       76
 106 \fBfd\fP\fIn\fP\fBu1760\fP      1760    80      22      2       96
 107 \fBfd\fP\fIn\fP\fBu1840\fP      1840    80      23      2       116
 108 \fBfd\fP\fIn\fP\fBu1920\fP      1920    80      24      2       100
 109 .TE
 110 .PP
 111 3.5 inch extra-density device files:
 112 .TS
 113 lw(1i) l l l l c
 114 lw(1i) c c c c c.
 115 Name    Capacity        Cyl.    Sect.   Heads   Base
 116         KiB                             minor #
 117 _
 118 \fBfd\fP\fIn\fP\fBu2880\fP      2880    80      36      2       32
 119 \fBfd\fP\fIn\fP\fBCompaQ\fP     2880    80      36      2       36
 120 \fBfd\fP\fIn\fP\fBu3200\fP      3200    80      40      2       104
 121 \fBfd\fP\fIn\fP\fBu3520\fP      3520    80      44      2       108
 122 \fBfd\fP\fIn\fP\fBu3840\fP      3840    80      48      2       112
 123 .TE
 124 .SH DESCRIPTION
 125 \fBfd\fP special files access the floppy disk drives in raw mode.
 126 The following
 127 .BR ioctl (2)
 128 calls are supported by \fBfd\fP devices:
 129 .TP
 130 .B FDCLRPRM
 131 clears the media information of a drive (geometry of disk in drive).
 132 .TP
 133 .B FDSETPRM
 134 sets the media information of a drive.
 135 The media information will be
 136 lost when the media is changed.
 137 .TP
 138 .B FDDEFPRM
 139 sets the media information of a drive (geometry of disk in drive).
 140 The media information will not be lost when the media is changed.
 141 This will disable autodetection.
 142 In order to reenable autodetection, you
 143 have to issue an \fBFDCLRPRM\fP.
 144 .TP
 145 .B FDGETDRVTYP
 146 returns the type of a drive (name parameter).
 147 For formats which work
 148 in several drive types, \fBFDGETDRVTYP\fP returns a name which is
 149 appropriate for the oldest drive type which supports this format.
 150 .TP
 151 .B FDFLUSH
 152 invalidates the buffer cache for the given drive.
 153 .TP
 154 .B FDSETMAXERRS
 155 sets the error thresholds for reporting errors, aborting the operation,
 156 recalibrating, resetting, and reading sector by sector.
 157 .TP
 158 .B FDSETMAXERRS
 159 gets the current error thresholds.
 160 .TP
 161 .B FDGETDRVTYP
 162 gets the internal name of the drive.
 163 .TP
 164 .B FDWERRORCLR
 165 clears the write error statistics.
 166 .TP
 167 .B FDWERRORGET
 168 reads the write error statistics.
 169 These include the total number of
 170 write errors, the location and disk of the first write error, and the
 171 location and disk of the last write error.
 172 Disks are identified by a
 173 generation number which is incremented at (almost) each disk change.
 174 .TP
 175 .B FDTWADDLE
 176 Switch the drive motor off for a few microseconds.
 177 This might be
 178 needed in order to access a disk whose sectors are too close together.
 179 .TP
 180 .B FDSETDRVPRM
 181 sets various drive parameters.
 182 .TP
 183 .B FDGETDRVPRM
 184 reads these parameters back.
 185 .TP
 186 .B FDGETDRVSTAT
 187 gets the cached drive state (disk changed, write protected et al.)
 188 .TP
 189 .B FDPOLLDRVSTAT
 190 polls the drive and return its state.
 191 .TP
 192 .B FDGETFDCSTAT
 193 gets the floppy controller state.
 194 .TP
 195 .B FDRESET
 196 resets the floppy controller under certain conditions.
 197 .TP
 198 .B FDRAWCMD
 199 sends a raw command to the floppy controller.
 200 .PP
 201 For more precise information, consult also the \fI<linux/fd.h>\fP and
 202 \fI<linux/fdreg.h>\fP include files, as well as the
 203 .BR floppycontrol (1)
 204 manual page.
 205 .SH FILES
 206 .I /dev/fd*
 207 .SH NOTES
 208 The various formats permit reading and writing many types of disks.
 209 However, if a floppy is formatted with an inter-sector gap that is too small,
 210 performance may drop,
 211 to the point of needing a few seconds to access an entire track.
 212 To prevent this, use interleaved formats.
 213 .PP
 214 It is not possible to
 215 read floppies which are formatted using GCR (group code recording),
 216 which is used by Apple II and Macintosh computers (800k disks).
 217 .PP
 218 Reading floppies which are hard sectored (one hole per sector, with
 219 the index hole being a little skewed) is not supported.
 220 This used to be common with older 8-inch floppies.
 221 .\" .SH AUTHORS
 222 .\" Alain Knaff (Alain.Knaff@imag.fr), David Niemi
 223 .\" (niemidc@clark.net), Bill Broadhurst (bbroad@netcom.com).
 224 .SH SEE ALSO
 225 .BR chown (1),
 226 .BR floppycontrol (1),
 227 .BR getfdprm (1),
 228 .BR mknod (1),
 229 .BR superformat (1),
 230 .BR mount (8),
 231 .BR setfdprm (8)