diff options
Diffstat (limited to 'Documentation/filesystems/affs.txt')
| -rw-r--r-- | Documentation/filesystems/affs.txt | 59 |
1 files changed, 35 insertions, 24 deletions
diff --git a/Documentation/filesystems/affs.txt b/Documentation/filesystems/affs.txt index 85d5a58b1..f63a6e3aa 100644 --- a/Documentation/filesystems/affs.txt +++ b/Documentation/filesystems/affs.txt @@ -1,8 +1,8 @@ -Amiga filesystems Overview -========================== +Overview of Amiga Filesystems +============================= Not all varieties of the Amiga filesystems are supported for reading and -writing. The Amiga currently knows 6 different filesystems: +writing. The Amiga currently knows six different filesystems: DOS\0 The old or original filesystem, not really suited for hard disks and normally not used on them, either. @@ -26,7 +26,7 @@ DOS\5 The Fast File System with directory cache. Supported read only. All of the above filesystems allow block sizes from 512 to 32K bytes. Supported block sizes are: 512, 1024, 2048 and 4096 bytes. Larger blocks -speed up almost everything with the expense of wasted disk space. The speed +speed up almost everything at the expense of wasted disk space. The speed gain above 4K seems not really worth the price, so you don't lose too much here, either. @@ -45,12 +45,13 @@ setgid[=gid] Same as above, but for gid. mode=mode Sets the mode flags to the given (octal) value, regardless of the original permissions. Directories will get an x - permission, if the corresponding r bit is set. + permission if the corresponding r bit is set. This is useful since most of the plain AmigaOS files will map to 600. reserved=num Sets the number of reserved blocks at the start of the - partition to num. Default is 2. + partition to num. You should never need this option. + Default is 2. root=block Sets the block number of the root block. This should never be necessary. @@ -66,16 +67,18 @@ verbose The volume name, file system type and block size will be written to the syslog when the filesystem is mounted. mufs The filesystem is really a muFS, also it doesn't - identify itself as one. This option is neccessary if + identify itself as one. This option is necessary if the filesystem wasn't formatted as muFS, but is used as one. prefix=path Path will be prefixed to every absolute path name of - symbolic links on an AFFS partition. Default = / + symbolic links on an AFFS partition. Default = "/". + (See below.) volume=name When symbolic links with an absolute path are created - on an AFFS partition, volume will be prepended as the + on an AFFS partition, name will be prepended as the volume name. Default = "" (empty string). + (See below.) Handling of the Users/Groups and protection flags ================================================= @@ -92,11 +95,13 @@ The Amiga protection flags RWEDRWEDHSPARWED are handled as follows: - H and P are always retained and ignored under Linux. - - A is always reset when written. + - A is always reset when a file is written to. User id and group id will be used unless set[gu]id are given as mount options. Since most of the Amiga file systems are single user systems -they will be owned by root. +they will be owned by root. The root directory (the mount point) of the +Amiga filesystem will be owned by the user who actually mounts the +filesystem (the root directory doesn't have uid/gid fields). Linux -> Amiga: @@ -111,7 +116,7 @@ The Linux rwxrwxrwx file mode is handled as follows: - All other flags (suid, sgid, ...) are ignored and will not be retained. -Newly created files and directories will get the user and group id +Newly created files and directories will get the user and group ID of the current user and a mode according to the umask. Symbolic links @@ -121,7 +126,7 @@ Although the Amiga and Linux file systems resemble each other, there are some, not always subtle, differences. One of them becomes apparent with symbolic links. While Linux has a file system with exactly one root directory, the Amiga has a separate root directory for each -file system (e.g. partition, floppy disk, ...). With the Amiga, +file system (for example, partition, floppy disk, ...). With the Amiga, these entities are called "volumes". They have symbolic names which can be used to access them. Thus, symbolic links can point to a different volume. AFFS turns the volume name into a directory name @@ -139,12 +144,12 @@ might be "User", "WB" and "Graphics", the mount points /amiga/User, Examples ======== -Command line - mount Archive/Amiga/Workbench3.1.adf /mnt -t affs -o loop,reserved=4 +Command line: + mount Archive/Amiga/Workbench3.1.adf /mnt -t affs -o loop,verbose mount /dev/sda3 /Amiga -t affs -/etc/fstab example - /dev/sdb5 /d/f affs ro +/etc/fstab entry: + /dev/sdb5 /amiga/Workbench affs noauto,user,exec,verbose 0 0 Bugs, Restrictions, Caveats =========================== @@ -159,10 +164,10 @@ can be changed by setting the compile-time option AFFS_NO_TRUNCATE in include/linux/amigaffs.h). Case is ignored by the affs in filename matching, but Linux shells -do care about the case. Example (with /mnt being an affs mounted fs): - rm /mnt/WRONGCASE +do care about the case. Example (with /wb being an affs mounted fs): + rm /wb/WRONGCASE will remove /mnt/wrongcase, but - rm /mnt/WR* + rm /wb/WR* will not since the names are matched by the shell. The block allocation is designed for hard disk partitions. If more @@ -170,14 +175,20 @@ than 1 process writes to a (small) diskette, the blocks are allocated in an ugly way (but the real AFFS doesn't do much better). This is also true when space gets tight. +You cannot execute programs on an OFS (Old File System), since the +program files cannot be memory mapped due to the 488 byte blocks. +For the same reason you cannot mount an image on such a filesystem +via the loopback device. + The bitmap valid flag in the root block may not be accurate when the system crashes while an affs partition is mounted. There's currently -no way to fix this without an Amiga (disk validator) or manually -(who would do this?). Maybe later. +no way to fix a garbled filesystem without an Amiga (disk validator) +or manually (who would do this?). Maybe later. A fsck.affs and mkfs.affs will probably be available in the future. -Until then, you should do - ln -s /bin/true /etc/fs/mkfs.affs +If you mount them on system startup, you may want to tell fsck +that the fs should not be checked (place a '0' in the sixth field +of /etc/fstab). It's not possible to read floppy disks with a normal PC or workstation due to an incompatibility with the Amiga floppy controller. |