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ltf(4)								       ltf(4)



NAME
  ltf -	labeled	tape facility

DESCRIPTION

  The term ltf (Labeled	Tape Facility) refers to the group of programs
  required to fulfill the features and functionality outlined here.

  References for the substance of this document	are based on:

    +  American	National Standard Institute magnetic tape labels and file
       structure for information interchange ANSI X3.27-1978

    +  The document/working paper: Draft Proposed Revision to ANSI X3.27-
       1978, Public Review Comment on ANSI X3L5/83-28T 15-Oct-84 (describes
       the version 4 ANSI standard)

  This proposed	implementation of the ltf does not claim to be 100% ANSI
  standard in all cases.  That is, the Tru64 UNIX ltf does not support the
  entirety of the functionality	or format capabilities outlined	in the
  documents/publications cited as references.

  It should be understood that the functionality and formats for Tru64 UNIX
  labeled tapes	are simply based on the	standards and formats referred to,
  and described	in, the	publications/documents listed previously.

  The ltf attempts to follow these documents as	working	precepts as accu-
  rately as it can, while meeting the needs of Tru64 UNIX systems.

  It should be further understood that where the cited documents specify pro-
  cedures or operational constricts that would conflict	with those
  features/functionality normally found	in a Tru64 UNIX	system,	the pro-
  cedures or operational constricts, by	necessity, have	been omitted from the
  ltf implementation.

  The goals of ltf are to create an accurate exchange of information between
  Tru64	UNIX systems and between Tru64 UNIX systems and	systems	other than
  Tru64	UNIX as	an import/export facility by providing a means to read/write
  tapes	in a format generally
  acceptable to	most systems providing support of ANSI-labeled tapes.

  It is	not a goal of ltf to provide the multivolume file sets or to provide
  100% of the ANSI specifications for the following labels on volumes gen-
  erated by other operating systems:

       VOL1
	   Accessibility Field
       VOL2 - VOL9
       UVL1 - UVL9 (User Volume	Labels)
       HDR1, EOV1, EOF1
	   File-set Identifier
	   Expiration Date
	   Accessibility Field
	   Block Count
       HDR2
	   Buffer Offset Content
       HDR3 - HDR9
       UHL1 - UHL9 (User Header	Labels)
       EOV3 - EOV9 (End	of Volume Labels)
       EOF3 - EOF9 (End	of File	Labels)
       ULT1 - UTL9 (User Trailer Labels)

  The FORMATS section provides the general ANSI	volume and label formats.
  Each label consists of 80 bytes of ASCII data	as specified.  Items enclosed
  in parentheses () indicate optional fields that may be present according to
  the ANSI standard.  The following terms are used as indicated:

  a	Refers to the sets of characters including uppercase (A-Z), numerals
	(0-9), and special characters (space ! " % & ' ( ) * + , - _ . / : ;
	< = > ?).

  BLOCK	A group	of consecutive bytes of	data treated as	a unit by the storage
	medium.	 Blocks	are separated by an interblock gap.  A block may con-
	tain part of a record, all of the record, or many records.

  BLOCK	LENGTH
	The minimum block size is 18 bytes and the maximum is 20480.

  RECORD
	A set of related data treated as a unit	of information.

  TAPE MARK
	A control block	used as	a delimiter.

  FORMATS for ANSI VERSION 3/4	-  MULTI-FILE /	SINGLE VOLUME

       bot	Beginning of tape marker
       VOL1	Volume Label (only 1 permitted for ANSI	version	3,
		ANSI version 4 OPTIONALLY permits Volume Labels
		2 through 9)
       (UVLn)	OPTIONAL User Volume labels ('n' varies	from 1 - 9)
       HDR1	First File Header Label
       HDR2	Second File Header Label
       (HDRn)	OPTIONAL File Header Labels ('n' varies	from 3 - 9)
       (UHLa)	OPTIONAL User File Header Labels (quantity
		unspecified)
       tm	Tape Mark
       DATA	data blocks of first file
       tm	Tape Mark
       EOF1	First End of File Label
       EOF2	Second End of File Label
       (EOFn)	OPTIONAL End of	File Labels ('n' varies	from 3 - 9)
       (UTLn)	OPTIONAL User Trailer Labels
       tm	Tape Mark

       HDR1	First File Header Label
       HDR2	Second File Header Label
       (HDRn)	OPTIONAL File Header Labels ('n' varies	from 3 - 9)
       (UHLa)	OPTIONAL User File Header Labels (number undefined)
       tm	Tape Mark
       DATA	data blocks of second file
       tm	Tape Mark
       EOF1	First End of File Label
       EOF2	Second End of File Label
       (EOFn)	OPTIONAL End of	File Labels ('n' varies	from 3 - 9)
       (UTLn)	OPTIONAL User Trailer Labels
       tm	Tape Mark

       HDR1	First File Header Label
	.
	.
	.
       tm	Tape Mark
       tm	Tape Mark

  VOL1 - Label Format -	ANSI VERSION 3

  The following	table identifies the volume and	supplies volume	security
  information:

       Size   First &  Description
       of     Last
       Field  Byte #   or Content
       -----  -------  -----------

       3      1	- 3    "VOL"
       1      4	       "1"
       6      5	- 10   Volume Identifier - user	specifiable "a"
		       characters, default = "ULTRIX"
       1      11       Accessibility Field - not implemented by	ltf
       26     12 - 37  Reserved	by ANSI	(spaces)
       14     38 - 51  Owner ID	- user defined "a" characters,
		       default = spaces
       28     52 - 79  Reserved	by ANSI	(spaces)
       1      80       Label Standard Version, 3 for ANSI Version 3

  VOL1 - Label Format -	ANSI VERSION 4

  The following	table identifies the volume and	supplies volume	security
  information:

       Size   First &  Description
       of     Last
       Field  Byte #   or Content
       -----  -------  -----------

       3      1	- 3    "VOL"
       1      4	       "1"
       6      5	- 10   Volume Identifier - user	specifiable "a"
		       characters, default = "ULTRIX"
       1      11       Accessibility Field - not implemented by	ltf
       13     12 - 24  Reserved	by ANSI	(spaces)
       13     25 - 37  Implementation ID - "a" characters, ULTRIX
		       default = "DECULTRIXnnnn", where	nnnn are
		       digits from 0000	to 9999, identifying the
		       version number of ltf which created volume
       14     38 - 51  Owner ID	- user defined "a" characters,
		       default = spaces
       28     52 - 79  Reserved	by ANSI	(spaces)
       1      80       Label Standard Version, 4 for ANSI Version 4

  HDR1 - Label Format -	ANSI VERSION 3/4

  The following	file header label identifies and describes the file.  Infor-
  mation in this label is limited to "a" characters only:

       Size   First &  Description
       of     Last
       Field  Byte #   or Content
       -----  -------  -----------

       3      1	- 3    "HDR"
       1      4	       "1"
       17     5	- 21   File ID - Interchange file name,	"a"
		       characters
       6      22 - 27  File Set	ID - "000001" since only one
		       file set	on single volume
       4      28 - 31  File Section Number - "0001"
       4      32 - 35  File Sequence Number - starts at	"0001"
		       and increments once for each file on volume
       4      36 - 39  Generation Number - "0001"
       2      40 - 41  Generation Version Number - "00"
       6      42 - 47  Creation	Date - Julian date, first character
		       denotes century,	" " = 1900, "0"	= 2000
       6      48 - 53  Expiration Date - Julian	date, not implemented
		       by ltf, set to "	99366"
       1      54       File Security - " "
       6      55 - 60  Block Count - "000000"
       13     61 - 73  Implementation ID - same	as in VOL1
       7      74 - 80  Reserved	by ANSI	(spaces)

  HDR2 - Label Format -	ANSI VERSION 3/4

  File header label describes the record format, maximum record	size, and
  maximum block	length of the file.  Information in this label is limited to
  "a" characters, except for the content of bytes 16 through 50	if the volume
  is ANSI version 4.  The contents of the field	in bytes 16 - 50 are for a
  Tru64	UNIX system implementation only; thus, if the volume is	not "ULTRIX",
  these	fields are ignored.

       Size   First &  Description
       of     Last
       Field  Byte #   or Content
       -----  -------  -----------

       3      1	- 3    "HDR"
       1      4	       "2"
       1      5	       Record Format - "F" = fixed length records
				       "D" = variable length records
				       "S" = segmented records
       5      6	- 10   Block Length - default =	"02048"
       5      11 - 15  Record Length - "F" format, length of each data
				       record
				       "D" format, maximum length of a
				       data record including record
				       control word
				       "S" format, maximum length of a
				       data record not including the
				       segment control word, if	scw =
				       "00000",	maximum	record length
				       may exceed 99999	bytes
       6      16 - 21  Tru64 UNIX File Status -	st_mode	returned from a
		       stat(2) call
       4      22 - 25  Tru64 UNIX File Owner ID	- uid
       4      26 - 29  Tru64 UNIX Owner	Group Number - gid
       4      30 - 33  Tru64 UNIX Link ID Sequence Number - if file is
		       hard linked, contains the file sequence number
		       of the file this	file is	linked to
       3      34 - 36  Tru64 UNIX True File Type - three character
		       representation of the Tru64 UNIX	disk file type
		       (see below)
       1      37       Carriage	Control	- "A" =	first byte of record
		       contains	FORTRAN	carriage control character
					  "M" =	record contains	all
					  required forms control
					  " " =	(space)	insert carriage
					  return, and line feed	between
					  records
       10     38 - 47  Tru64 UNIX File Size - in bytes if known, else
		       spaces
       1      48       Tru64 UNIX ltf Header Number - number of	last HDR
		       containing the full Tru64 UNIX pathname of the
		       file, digit between 3 and 9
       1      49       Tru64 UNIX ltf End of File Header Number	-
		       number of last EOF containing the full Tru64 UNIX
		       pathname	of the file, digit between 3 and 9,
		       if "0", no path name in EOFs
       1      50       Tru64 UNIX Hard Link Flag - necessary when the file
		       linked to has not been put on the volume, thus
		       this flag is used for forward references, "0" =
		       no links	or symbolic link, "1" =	hard links
       2      51 - 52  Buffer Offset - number of bytes of Buffer
		       Offset Field, which is the first	record in
		       the data	block, if the Buffer Offset is greater
		       than zero, not implemented by ltf and set to "00"
       28     53 - 80  ANSI reserved (spaces)

  The Tru64 UNIX disk file type	is described in	field 34-36 of HDR2.  The
  following list contains the 3-character representations you can use to
  specify the disk file	type:

       "adf"	 - ASCII data file
       "asc"	 - ASCII text
       "arc"	 - Archive
       "arl"	 - Archive Random Library
       "asm"	 - Assembly language text
       "bg5"	 - Big-5 text file
       "bin"	 - Binary data
       "bsp"	 - Block special file
       "cc "	 - 'C' program text
       "cmp"	 - Compressed text file
       "com"	 - Command text	file
       "cpi"	 - CPIO	file
       "csp"	 - Character special file
       "dir"	 - Directory
       "eJP"	 - Japanese EUC	text file
       "eKR"	 - Korean EUC text file
       "eng"	 - English text
       "eTW"	 - Taiwanese EUC text file
       "exe"	 - Executable binary
       "for"	 - Fortran program source
       "fuf"	 - Fortran Unformatted File
       "hyu"	 - DEC Hanyu text file
       "hzi"	 - DEC Hanzi text file
       "knj"	 - DEC Kanji text file
       "kor"	 - DEC Korean text file
       "mbT"	 - Multibyte text file
       "nul"	 - Null/empty file
       "oar"	 - Old Archive
       "pip"	 - Named pipe
       "rof"	 - roff, nroff,	troff, or eqn input text
       "sbT"	 - Single-byte text file
       "skj"	 - Super DEC Kanji text	file
       "soc"	 - Socket
       "sym"	 - Symbolic Link
       "ISO"	 - ISO 8859-1 text file
       "SJS"	 - Shift JIS text file
       "TTS"	 - TACTIS (Thai) text file
       "???"	 - Content of file not determined

  HDR3 - Label Format -	ANSI VERSION 3/4

  OPTIONAL file	header label presence and content ignored if the volume	was
  not created by a Tru64 UNIX system.  Content limited to "a" characters if
  VOL1 field 80	= "3".	Embedded spaces	in the path names are not permitted.


       Size   First &  Description
       of     Last
       Field  Byte #   or Content
       -----  -------  -----------

       3      1	- 3    "HDR"
       1      4	       "3"
       10     5	- 14   Tru64 UNIX standard time	of last	change to file
       10     15 - 24  Tru64 UNIX File Owner Name
       20     25 - 44  Tru64 UNIX Hostname
       36     45 - 80  Tru64 UNIX File Path Name - first 36 characters

  HDR4 through HDR9 - Label Format - ANSI VERSION 3/4

  OPTIONAL file	header label used by the ltf to	express	some fractional	com-
  ponent of the	file's complete	path name, but presence	and content ignored
  if the volume	was not	created	by a Tru64 UNIX	system.	 Content limited to
  "a" characters if VOL1 field 80 = "3".

       Size   First &  Description
       of     Last
       Field  Byte #   or Content
       -----  -------  -----------

       3      1	- 3    "HDR"
       1      4	       "4" - "9"
       76     5	- 80   Tru64 UNIX File Path Name - continuation	from
		       previous	HDR, left justified and	padded with
		       blanks if needed

  BUHLa	- Label	Format - ANSI VERSION 3/4

  OPTIONAL User	File Header Labels not supported by the	ltf.  They are not
  output and, if present on an input volume, their presence and	content	is
  ignored.

       Size   First &  Description
       of     Last
       Field  Byte # or	Content
       -----  ------- -----------

       3      1	- 3    "UHL"
       1      4	       any valid "a" character identifying this	label
       76     5	- 80   Application Dependent

  EOV1 - Label Format -	ANSI VERSION 3/4

  First	End-Of-Volume label that, if read before the first End Of File label
  (EOF1), indicates that the file is continued on the next volume.  For	valid
  hardware and software	technical limitations, the Tru64 UNIX implementation
  of ltf does not support multivolume file sets	and therefore does not output
  these	labels.	 If present on an input	volume,	they are interpreted as	indi-
  cating an error condition, due to the	fact that some portion of the file
  will not be processed.  The fields of	this label are identical to the	con-
  tents	of the corresponding fields in the First File Header Label (HDR1),
  with the exceptions noted below.  The	following diagrams of EOV labels are
  intended for reference purposes only.

       Size   First &  Description
       of     Last
       Field  Byte #   or Content
       -----  ------- -----------

       3      1	- 3    "EOV"
       1      4	       "1"
       50     5	- 54   same as corresponding fields in HDR1
       6      55 - 60  Block Count - number of blocks in which the
		       file was	recorded
       20     61 - 80  same as corresponding fields in HDR1

  EOV2 - Label Format -	ANSI VERSION 3/4

  The fields of	the Second End-Of-Volume label are identical to	the contents
  of the corresponding fields in the Second File Header	Label (HDR2), with
  the exceptions noted.	 The ltf does not support the use of EOV labels. See
  the previous description for EOV1.  OPTIONAL End-Of-Volume labels 3 through
  9  (EOV3 - EOV9) are not used	by the ltf.  If	present	on an input volume,
  their	presence and content are ignored by the	ltf.  See NOTES	for EOV1.

       Size   First &  Description
       of     Last
       Field  Byte #   or Content
       -----  -------  -----------

       3      1	- 3    "EOV"
       1      4	       "2"
       76     5	- 80   same as corresponding fields in HDR2

  EOF1 - Label Format -	ANSI VERSION 3/4

  The fields of	the First End-Of-File label are	identical to the contents of
  the corresponding fields in the First	File Header Label (HDR1), with the
  exceptions noted.

       Size   First &  Description
       of     Last
       Field  Byte #   or Content
       -----  ------- -----------

       3      1	- 3    "EOF"
       1      4	       "1"
       50     5	- 54   same as corresponding fields in HDR1
       6      55 - 60  Block Count - number of blocks in which the
		       file was	recorded
       20     61 - 80  same as corresponding fields in HDR1

  EOF2 - Label Format -	ANSI VERSION 3/4

  The fields of	the Second End-Of-File label are identical to the contents of
  the corresponding fields in the Second File Header Label (HDR2).

       Size   First &  Description
       of     Last
       Field  Byte #   or Content
       -----  -------  -----------

       3      1	- 3    "EOF"
       1      4	       "2"
       76     5	- 80   same as corresponding fields in HDR2

  EOF3 through EOF9 - Label Format - ANSI VERSION 3/4

  OPTIONAL ANSI	end-of-file labels used	by the ltf to express some fractional
  component of the file's complete path	name.  The presence and	content	of
  these	labels are ignored if the volume was not created by a Tru64 UNIX sys-
  tem.	Content	limited	to "a" characters if VOL1 field	80 = "3".

       Size   First &  Description
       of     Last
       Field  Byte #   or Content
       -----  -------  -----------

       3      1	- 3    "EOF"
       1      4	       "3" - "9"
       76     5	- 80   Tru64 UNIX File Path Name - continuation	from
		       HDR9 and	previous EOF, left justified and
		       padded with blanks if needed

  UTLa through UTLa - Label Format - ANSI VERSION 3/4

  OPTIONAL User	File Trailer Labels Set	is optional.  If present on an input
  volume, it is	ignored	by the ltf.  User File Trailer Labels are not output
  by the ltf.  If present, they	take the form described.  Their	use is appli-
  cation dependent but not supported by	the ltf.

       Size   First &  Description
       of     Last
       Field  Byte #   or Content
       -----  -------  -----------

       3      1	- 3    "UTL"
       1      4	       any valid "a" character identifying this	label
       76     5	- 80   Application Dependent

RELATED	INFORMATION

  ltf(1)