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Documentation / filesystems / adfs.txt




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Based on kernel version 3.15.4. Page generated on 2014-07-07 09:02 EST.

1	Mount options for ADFS
2	----------------------
3	
4	  uid=nnn	All files in the partition will be owned by
5			user id nnn.  Default 0 (root).
6	  gid=nnn	All files in the partition will be in group
7			nnn.  Default 0 (root).
8	  ownmask=nnn	The permission mask for ADFS 'owner' permissions
9			will be nnn.  Default 0700.
10	  othmask=nnn	The permission mask for ADFS 'other' permissions
11			will be nnn.  Default 0077.
12	  ftsuffix=n	When ftsuffix=0, no file type suffix will be applied.
13			When ftsuffix=1, a hexadecimal suffix corresponding to
14			the RISC OS file type will be added.  Default 0.
15	
16	Mapping of ADFS permissions to Linux permissions
17	------------------------------------------------
18	
19	  ADFS permissions consist of the following:
20	
21		Owner read
22		Owner write
23		Other read
24		Other write
25	
26	  (In older versions, an 'execute' permission did exist, but this
27	   does not hold the same meaning as the Linux 'execute' permission
28	   and is now obsolete).
29	
30	  The mapping is performed as follows:
31	
32		Owner read				-> -r--r--r--
33		Owner write				-> --w--w---w
34		Owner read and filetype UnixExec	-> ---x--x--x
35	    These are then masked by ownmask, eg 700	-> -rwx------
36		Possible owner mode permissions		-> -rwx------
37	
38		Other read				-> -r--r--r--
39		Other write				-> --w--w--w-
40		Other read and filetype UnixExec	-> ---x--x--x
41	    These are then masked by othmask, eg 077	-> ----rwxrwx
42		Possible other mode permissions		-> ----rwxrwx
43	
44	  Hence, with the default masks, if a file is owner read/write, and
45	  not a UnixExec filetype, then the permissions will be:
46	
47				-rw-------
48	
49	  However, if the masks were ownmask=0770,othmask=0007, then this would
50	  be modified to:
51				-rw-rw----
52	
53	  There is no restriction on what you can do with these masks.  You may
54	  wish that either read bits give read access to the file for all, but
55	  keep the default write protection (ownmask=0755,othmask=0577):
56	
57				-rw-r--r--
58	
59	  You can therefore tailor the permission translation to whatever you
60	  desire the permissions should be under Linux.
61	
62	RISC OS file type suffix
63	------------------------
64	
65	  RISC OS file types are stored in bits 19..8 of the file load address.
66	
67	  To enable non-RISC OS systems to be used to store files without losing
68	  file type information, a file naming convention was devised (initially
69	  for use with NFS) such that a hexadecimal suffix of the form ,xyz
70	  denoted the file type: e.g. BasicFile,ffb is a BASIC (0xffb) file.  This
71	  naming convention is now also used by RISC OS emulators such as RPCEmu.
72	
73	  Mounting an ADFS disc with option ftsuffix=1 will cause appropriate file
74	  type suffixes to be appended to file names read from a directory.  If the
75	  ftsuffix option is zero or omitted, no file type suffixes will be added.
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