1 .. SPDX-License-Identifier: GPL-2.0
2
3 =============================
4 Overview of Amiga Filesystems
5 =============================
6
7 Not all varieties of the Amiga filesystems are
8 writing. The Amiga currently knows six differe
9
10 ============== ==============================
11 DOS\0 The old or original filesystem
12 hard disks and normally not us
13 Supported read/write.
14
15 DOS\1 The original Fast File System.
16
17 DOS\2 The old "international" filesy
18 a bug has been fixed so that a
19 in file names are case-insensi
20 Supported read/write.
21
22 DOS\3 The "international" Fast File
23
24 DOS\4 The original filesystem with d
25 cache speeds up directory acce
26 but slows down file creation/d
27 sense on hard disks. Supported
28
29 DOS\5 The Fast File System with dire
30 ============== ==============================
31
32 All of the above filesystems allow block sizes
33 Supported block sizes are: 512, 1024, 2048 and
34 speed up almost everything at the expense of w
35 gain above 4K seems not really worth the price
36 much here, either.
37
38 The muFS (multi user File System) equivalents
39 are supported, too.
40
41 Mount options for the AFFS
42 ==========================
43
44 protect
45 If this option is set, the pro
46
47 setuid[=uid]
48 This sets the owner of all fil
49 system to uid or the uid of th
50
51 setgid[=gid]
52 Same as above, but for gid.
53
54 mode=mode
55 Sets the mode flags to the giv
56 of the original permissions. D
57 permission if the correspondin
58 This is useful since most of t
59 will map to 600.
60
61 nofilenametruncate
62 The file system will return an
63 standard maximum filename leng
64
65 reserved=num
66 Sets the number of reserved bl
67 partition to num. You should n
68 Default is 2.
69
70 root=block
71 Sets the block number of the r
72 be necessary.
73
74 bs=blksize
75 Sets the blocksize to blksize.
76 1024, 2048 and 4096. Like the
77 never be necessary, as the aff
78
79 quiet
80 The file system will not retur
81 mode changes.
82
83 verbose
84 The volume name, file system t
85 be written to the syslog when
86
87 mufs
88 The filesystem is really a muF
89 identify itself as one. This o
90 the filesystem wasn't formatte
91 as one.
92
93 prefix=path
94 Path will be prefixed to every
95 symbolic links on an AFFS part
96 (See below.)
97
98 volume=name
99 When symbolic links with an ab
100 on an AFFS partition, name wil
101 volume name. Default = "" (emp
102 (See below.)
103
104 Handling of the Users/Groups and protection fl
105 ==============================================
106
107 Amiga -> Linux:
108
109 The Amiga protection flags RWEDRWEDHSPARWED ar
110
111 - R maps to r for user, group and others. On
112
113 - W maps to w.
114
115 - E maps to x.
116
117 - D is ignored.
118
119 - H, S and P are always retained and ignored
120
121 - A is cleared when a file is written to.
122
123 User id and group id will be used unless set[g
124 options. Since most of the Amiga file systems
125 they will be owned by root. The root directory
126 Amiga filesystem will be owned by the user who
127 filesystem (the root directory doesn't have ui
128
129 Linux -> Amiga:
130
131 The Linux rwxrwxrwx file mode is handled as fo
132
133 - r permission will allow R for user, group
134
135 - w permission will allow W for user, group
136
137 - x permission of the user will allow E for
138
139 - D will be allowed for user, group and othe
140
141 - All other flags (suid, sgid, ...) are igno
142 not be retained.
143
144 Newly created files and directories will get t
145 of the current user and a mode according to th
146
147 Symbolic links
148 ==============
149
150 Although the Amiga and Linux file systems rese
151 are some, not always subtle, differences. One
152 with symbolic links. While Linux has a file sy
153 root directory, the Amiga has a separate root
154 file system (for example, partition, floppy di
155 these entities are called "volumes". They have
156 can be used to access them. Thus, symbolic lin
157 different volume. AFFS turns the volume name i
158 and prepends the prefix path (see prefix optio
159
160 Example:
161 You mount all your Amiga partitions under /ami
162 <volume> is the name of the volume), and you g
163 "prefix=/amiga/" when mounting all your AFFS p
164 might be "User", "WB" and "Graphics", the moun
165 /amiga/WB and /amiga/Graphics). A symbolic lin
166 "User:sc/include/dos/dos.h" will be followed t
167 "/amiga/User/sc/include/dos/dos.h".
168
169 Examples
170 ========
171
172 Command line::
173
174 mount Archive/Amiga/Workbench3.1.adf /mnt
175 mount /dev/sda3 /Amiga -t affs
176
177 /etc/fstab entry::
178
179 /dev/sdb5 /amiga/Workbench affs no
180
181 IMPORTANT NOTE
182 ==============
183
184 If you boot Windows 95 (don't know about 3.x,
185 have an Amiga harddisk connected to your PC, i
186 the bytes 0x00dc..0x00df of block 0 with garba
187 the Rigid Disk Block. Sheer luck has it that t
188 area of the RDB, so only the checksum doesn't
189 Linux will ignore this garbage and recognize t
190 before you connect that drive to your Amiga ag
191 restore or repair your RDB. So please do make
192 before booting Windows!
193
194 If the damage is already done, the following s
195 (where <disk> is the device name).
196
197 DO AT YOUR OWN RISK::
198
199 dd if=/dev/<disk> of=rdb.tmp count=1
200 cp rdb.tmp rdb.fixed
201 dd if=/dev/zero of=rdb.fixed bs=1 seek=220 c
202 dd if=rdb.fixed of=/dev/<disk>
203
204 Bugs, Restrictions, Caveats
205 ===========================
206
207 Quite a few things may not work as advertised.
208 tested, though several hundred MB have been re
209 this fs. For a most up-to-date list of bugs pl
210 fs/affs/Changes.
211
212 By default, filenames are truncated to 30 char
213 'nofilenametruncate' mount option can change t
214
215 Case is ignored by the affs in filename matchi
216 do care about the case. Example (with /wb bein
217
218 rm /wb/WRONGCASE
219
220 will remove /mnt/wrongcase, but::
221
222 rm /wb/WR*
223
224 will not since the names are matched by the sh
225
226 The block allocation is designed for hard disk
227 than 1 process writes to a (small) diskette, t
228 in an ugly way (but the real AFFS doesn't do m
229 is also true when space gets tight.
230
231 You cannot execute programs on an OFS (Old Fil
232 program files cannot be memory mapped due to t
233 For the same reason you cannot mount an image
234 via the loopback device.
235
236 The bitmap valid flag in the root block may no
237 system crashes while an affs partition is moun
238 no way to fix a garbled filesystem without an
239 or manually (who would do this?). Maybe later.
240
241 If you mount affs partitions on system startup
242 fsck that the fs should not be checked (place
243 of /etc/fstab).
244
245 It's not possible to read floppy disks with a
246 due to an incompatibility with the Amiga flopp
247
248 If you are interested in an Amiga Emulator for
249
250 http://web.archive.org/web/%2E/http://www.frei
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