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