File header labels (HDR1 through HDR9)

Each file or file section contains at least two file header labels (HDR1 and HDR2) and at most nine. File header labels HDR3 through HDR9 are optional.

First file header label (HDR1)

The first file header label identifies a file section, describes its location within the file set and defines certain attributes of the file section.

Format

Position	Field name	Length	Contents
1 to 3	Label identifier	3	HDR
4	Label number	1	1
5 to 21	File name	17	“a” characters. Identifies the file.
22 to 27	File set identifier	6	“a” characters. Identifies the file set to which this file belongs.
28 to 31	File section number	4	“n” characters. Identifies the file section. The number of the first file section in a file is 0001. This number is incremented by one for every subsequent file section in this file.
32 to 35	File sequence number	4	“n” characters. Identifies the file in the file set. The file sequence number of the first file in a file set is 0001. This number is incremented by one for each subsequentfile in this file set. This field must contain the same number in all the labels of a specific file, regardless of whether the file is contained on one or more volumes.
36 to 39	Generation numbers	4	“n” characters. Distinguishes the successive extensions/updates of the file from 0001 through 9999.
40 to 41	Version number	2	“n” characters. Distinguishes the successive repetitions of a generation.
42 to 47	Creation date	6	Spaces or “n” characters. Specifies the creation date of the file section. A space indicates the 20th century; the digit 0 indicates the 21st century, followed by two “n” characters (00 - 99) indicating the year within the century, followed by three “n” characters (001 - 366) indicating the day of the year. The value 00000 in the last five places indicates that the creation date is irrelevant. The value 00000 in the last five places indicates that the creation date is irrelevant.
48 to 53	Expiration date	6	Spaces or “n” characters. Specifies the earliest date on which the file section may be deleted. The format is the same as for the “creation date” field (positions 42 - 47). The value 00000 in the last five places indicates that the expiration date is irrelevant and that the file section is obsolete.
54	File access indicator	1	“a” characters. Indicates restrictions with regard to access to data in this file. A space indicates that there are no restrictions with regard to accessing the file. Any other “a” character indicates that there are special restrictions governing access to the file. BS2000: with “1” or “3” tape or file owner has access authorization.
55 to 60	Block count	6	000000
61 to 73	System code	13	“a” characters. identifies the implementation responsible for creating the labels.
61 to 65		5	BS2000: Spaces.
66 to 73		8	BS2000: Spaces.
74 to 80	Reserved for future standardization	7	Spaces.

 

Second file header label (HDR2)

The second file header label describes certain attributes of the file and of the implementation.

Format

Position	Field name	Length	Contents
1 to 3	Label identifier	3	HDR
4	Label number	1	2
5	record format	1	F, D or S, and V and U (not supported according to DIN); specifies the format of the records in the file. F: all the records in the file have a fixed record length. D: all the records in the file have a variable record length and the number of characters (as a decimal) is specified in the record itself. S: all the records are segmented. U: all the records have an undefined length (not supported according to DIN). V: all the records are variable in length and the number of characters (in binary form) is specified in the record itself (not supported according to DIN).
6 to 10	Block length	5	“n” characters. Specifies the maximum number of characters per block in the file. BS2000: With standard identifier 1 the following contents are possible:
6 to 7	Standard blocks		“80”: standard block identifier.
8 to 10			“n” characters. Specifies the number of standard blocks.
11 to 15	Record length	5	“n” characters. Identifies the record length in conjunction with the record format (position 5). With record format F this field contains the actual record length. With record formats D and V this field contains the maximum length, including the record length word (RLW). With record format S this field contains the maximum record length, excluding the segment control words (SCW). If this field contains 00000 with record format S, it means that the record length may be greater than 99999. With record format U, this field contains the maximum number of characters that may be contained in one record.
16 to 50	Reserved for the implementation	35	There are no conventions or restrictions with regard to the recording and contents of this field.
16	Recording density	1	BS2000 assignments up to support of DIN level 4: 0 = 200 Bpi 1 = 556 Bpi 2 = 800 Bpi 3 = 1600 Bpi 4 = 6250 Bpi
17	Data position	1	Indicator in the case of track swapping: 0 = no 1 = yes
18 to 34	Job step	17	ID assigned by task management
35 to 36	Recording density for tape cartridges	2	2 spaces = not compressed “P” and space = compressed
47 to 50	File name code	4	Used only up to DIN 66029-1 if positions 6 and 7 contain standard blocks.
51 to 52	Buffer displacement	2	“n” characters. Specifies the length (in characters) of an additional field that is placed at the beginning of each block.
53 to 80	Reserved for future standardization	28	Spaces.

 

Third file header label (HDR3)

The HDR3 label contains the complete file name, the passwords and the access mode relevant for the file owner.

Format

Position	Field name	Length	Contents
1 to 3	Label identifier	3	HDR
4	Label number	1	3
5 to 12	Owner identifier	8	Identifies the owner of the file (user ID).
13 to 56	File name	44	The first 44 characters of the name of the file or file generationto which the file belongs.
57 to 60	read password	4	Specifies a password governing read access to the file.
61 to 64	write password	4	Specifies a password governing read and write access to the file.
65 to 68	Execute password	4	Specifies a password that must be entered in order to execute a load module contained in the file.
69	Access method	1	Specifies the valid access mode: 0 : read and write access permitted. 1 : only read access permitted.
70 to 80	Reserved	11	Spaces.

Optional file header labels (HDR4 through HDR9)

The other file header labels are optional and contain implementation-specific information.

Format

Position	Field name	Length	Contents
1 to 3	Label identifier	3	HDR
4	Label number	1	Digits 4 through 9
5 to 80	Reserved for the implementation	76	There are no conventions or restrictions with regard to the recording and contents of this field.