NAME

omap − optical file system index map

SYNOPSIS

omap [−is] [−b size] [−f size] [−l length] [−q quota] [−r [date]] [-volume] od [filename ...]

DESCRIPTION

omap extracts or constructs index records in an optical file system.  The file system od is a character-special device node referencing the od device driver or an ordinary file containing an optical file system.  If any filenames are specified, an index map of the selected files is generated on the standard output. If no filenames are specified, and od is not writable, an index map of all files is generated.  Otherwise, index map text is accepted on the standard input. 

The map text comprises one line for each file mapped.  The initial portion of an index map line (up to the first space) represents the path name of the file relative to the root of the file system.  Special characters in the remainder of the line identify specific fields in the file index record:

space The following value is the user code in decimal. 

.  The following value is the group code in decimal. 

, The following value is the file update time in date format %y/%m/%d_%H:%M:%S (see date(1)).  The first time value sets the create and modify times; the second time value sets only the modify time. 

∗ The following value is the file mode in octal. 

= The following value is the file size in decimal. 

; The following value is the number of blocks in the next logical range of data blocks in the file. 

@ The following value is the initial block number in the next logical range of data blocks in the file. 

If no address is specified for a range of logical blocks in a file, that range of logical blocks remains unmapped.  Unmapped blocks within a file appear as all-zero blocks. 

OPTIONS

−b The following value is the logical block size in bytes.  This number must be a power of two not less than 256.  The true block size is sensed automatically whenever an optical volume is accessed, so this option is used only for testing.  The default block size is 512 bytes. 

−f Emulate an optical file system in an ordinary file.  The following value specifies the size of the file in megabytes.  od names the file to be used, which must already exist.  The default file size is 1 megabyte. 

−i Invert the byte order of numeric fields when writing index records and directory entries.  This option may be specified to maintain consistency on file systems imported from machines employing a different byte order in numeric values.  It only controls the byte order written; index records and directories recorded in either byte order will always be interpreted correctly. 

−l The following value is the file buffer length in blocks.  To optimize access latency, physical data transfers from the optical storage media are accumulated and performed several blocks at a time.  This parameter may be varied to take optimal advantage of the characteristics of various optical disk drives.  The default buffer length is 96 kilobytes. 

−q The following value is the maximum number of contiguous errors accepted without producing a fatal I/O fault.  If this value is zero, no error quota is imposed.  The default error quota is 24. 

−r Read — A map of index records is sent to the standard output.  This option is assumed if any filenames are specified, or if od is not writable.  Otherwise, a map of index records is read from the standard input. 

The following value, if supplied, represents a time in the past to which the file system should regress.  All files and directories on the volume will appear exactly as they were at that instant in time.  More recent files and changes will disappear, and deleted or altered files will be restored to their previous state.  The regression time is specified as a single number in any of the forms DD, MMDD, MMDDYY, MMDDhhmm or MMDDYYhhmm, where YY, MM and DD represent the year, month and day, respectively, and hh and mm represent the hour and minute.  An initial zero may be omitted.  If the month or year is not specified, the most recent matching date is selected.  If the hour or minute is not specified, zero is assumed. 

−s Slow — Examine every file index record while accessing a file system.  The normal fast sequence locates file index records using an index map.  If any record cannot be read, the corresponding file cannot be accessed.  Using the slow option allows an earlier version of such an index record to be identified. 

−# Specify the volume reference number.  This informs omap where the volume was previously mounted so it can find the volume index map and cache files.  The volume reference number is the minor device number of the OFS device node used to mount the volume (see omount(8)). 

EXAMPLES

To produce a map of an optical file system:
omap -r /dev/od0 > map

To obtain a map of a specific optical file:
omap /dev/od0 file > map

To incorporate a fresh or revised file map:
omap /dev/od0 < map

FILES

/ofs/#<volume> optical disk volume index map. 

/ofs/$<volume> optical disk volume index cache. 

SEE ALSO

ofs(4), ofsd(8), ofsck(8), ofind(8), ofile(8), omount(8)

  —  30 June 1992