1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
|
<HTML
><HEAD
><TITLE
>The root filesystem</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
REL="HOME"
TITLE="The Linux System Administrator's Guide"
HREF="index.html"><LINK
REL="UP"
TITLE="Overview of the Directory Tree"
HREF="dir-tree-overview.html"><LINK
REL="PREVIOUS"
TITLE="Background"
HREF="x282.html"><LINK
REL="NEXT"
TITLE="The /etc directory"
HREF="x416.html"></HEAD
><BODY
CLASS="sect1"
BGCOLOR="#FFFFFF"
TEXT="#000000"
LINK="#0000FF"
VLINK="#840084"
ALINK="#0000FF"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>The Linux System Administrator's Guide: </TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="x282.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
>Chapter 4. Overview of the Directory Tree</TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="x416.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="sect1"
><H1
CLASS="sect1"
><A
NAME="AEN336"
></A
>4.2. The root filesystem</H1
><P
>The root filesystem should generally be small, since
it contains very critical files and a small, infrequently
modified filesystem has a better chance of not getting corrupted.
A corrupted root filesystem will generally mean that the system
becomes unbootable except with special measures (e.g., from a
floppy), so you don't want to risk it.</P
><P
>The root directory generally doesn't contain any files, except
perhaps the standard boot image for the system, usually called
<TT
CLASS="filename"
>/vmlinuz</TT
>. All other files are in
subdirectories in the root filesystems:
<DIV
CLASS="glosslist"
><DL
><DT
><B
><TT
CLASS="filename"
>/bin</TT
></B
></DT
><DD
><P
>Commands needed during bootup
that might be used by normal users (probably after
bootup).</P
></DD
><DT
><B
><TT
CLASS="filename"
>/sbin</TT
></B
></DT
><DD
><P
>Like <TT
CLASS="filename"
>/bin</TT
>, but the
commands are not intended for normal users, although they
may use them if necessary and allowed.
<TT
CLASS="filename"
>/sbin</TT
> is not usually in the default
path of normal users, but will be in root's default
path.</P
></DD
><DT
><B
><TT
CLASS="filename"
>/etc</TT
></B
></DT
><DD
><P
>Configuration files specific to the
machine.</P
></DD
><DT
><B
><TT
CLASS="filename"
>/root</TT
></B
></DT
><DD
><P
>The home directory for user root. This is
usually not accessible to other users on the
system</P
></DD
><DT
><B
><TT
CLASS="filename"
>/lib</TT
></B
></DT
><DD
><P
>Shared libraries needed by the programs on
the root filesystem.</P
></DD
><DT
><B
><TT
CLASS="filename"
>/lib/modules</TT
></B
></DT
><DD
><P
>Loadable kernel modules, especially those
that are needed to boot the system when recovering from
disasters (e.g., network and filesystem
drivers).</P
></DD
><DT
><B
><TT
CLASS="filename"
>/dev</TT
></B
></DT
><DD
><P
>Device files. Some of the more commonly
used device files are examined in <A
HREF="device-list.html"
>Chapter 5</A
>
</P
></DD
><DT
><B
><TT
CLASS="filename"
>/tmp</TT
></B
></DT
><DD
><P
>Temporary files. Programs running after
bootup should use <TT
CLASS="filename"
>/var/tmp</TT
>, not
<TT
CLASS="filename"
>/tmp</TT
>, since the former is probably on a
disk with more space. Often /tmp will be a symbolic link to
/var/tmp.</P
></DD
><DT
><B
><TT
CLASS="filename"
>/boot</TT
></B
></DT
><DD
><P
>Files used by the bootstrap loader,
e.g., LILO. Kernel images are often kept here instead
of in the root directory. If there are many kernel
images, the directory can easily grow rather big, and it
might be better to keep it in a separate filesystem.
Another reason would be to make sure the kernel
images are within the first 1024 cylinders of an IDE
disk.
<A
NAME="AEN392"
HREF="#FTN.AEN392"
><SPAN
CLASS="footnote"
>[1]</SPAN
></A
>
</P
></DD
><DT
><B
><TT
CLASS="filename"
>/mnt</TT
></B
></DT
><DD
><P
>Mount point for temporary mounts by
the system administrator. Programs aren't supposed to mount
on <TT
CLASS="filename"
>/mnt</TT
> automatically.
<TT
CLASS="filename"
>/mnt</TT
> might be divided into
subdirectories (e.g., <TT
CLASS="filename"
>/mnt/dosa</TT
> might
be the floppy drive using an MS-DOS filesystem, and
<TT
CLASS="filename"
>/mnt/exta</TT
> might be the same
with an ext2 filesystem).</P
></DD
><DT
><B
><TT
CLASS="filename"
>/proc</TT
>,
<TT
CLASS="filename"
>/usr</TT
>, <TT
CLASS="filename"
>/var</TT
>,
<TT
CLASS="filename"
>/home</TT
></B
></DT
><DD
><P
>Mount points
for the other filesystems.
<A
NAME="AEN412"
HREF="#FTN.AEN412"
><SPAN
CLASS="footnote"
>[2]</SPAN
></A
>
</P
></DD
></DL
></DIV
>
</P
></DIV
><H3
CLASS="FOOTNOTES"
>Notes</H3
><TABLE
BORDER="0"
CLASS="FOOTNOTES"
WIDTH="100%"
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="5%"
><A
NAME="FTN.AEN392"
HREF="x336.html#AEN392"
><SPAN
CLASS="footnote"
>[1]</SPAN
></A
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="95%"
><P
>This 1024 cylinder limit is no
longer true in most cases. With modern BIOSes and
later versions of LILO (the LInux LOader) the 1024
cylinder limit can be passed with logical block
addressing (LBA). See the <B
CLASS="command"
>lilo</B
>
manual page for more details.</P
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="5%"
><A
NAME="FTN.AEN412"
HREF="x336.html#AEN412"
><SPAN
CLASS="footnote"
>[2]</SPAN
></A
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="95%"
><P
>Although <TT
CLASS="filename"
>/proc</TT
> does not
reside on any disk in reality. See the section about
<TT
CLASS="filename"
>/proc</TT
> later in the
chapter.</P
></TD
></TR
></TABLE
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="x282.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="x416.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Background</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="dir-tree-overview.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>The <TT
CLASS="filename"
>/etc</TT
> directory</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>
|
