Header files

Through the OSFI, it is possible to access information about an item such as update stamps, permissions, ownership, and driver-specific data. The header driver translates this information into a format that looks like a standard D3 item.

Note: Access to the header information via this driver is read-only. The only way to modify the header information is through the normal update routines. This is enabled via the Y correlative for D3 files. With the Y correlative, the user, PIB, and/or timedate can be stamped by appending a u, p, and/or t to the y character. No other information is currently available for normal items. Header information updates on non-D3 items depend on the behavior of the remote file system to which those items belong.

Any utility that physically moves the data (such as copy) changes the header information.

The save and restore utilities save and restore the header information as well.

Raw attribute definitions

When reading items via the header driver, the items are returned as a dynamic array with the following raw attribute definitions:

Note: Attributes 11-14 apply only for UNIX.

Attribute	Description	md Entry
1 User-ID	D3 user name or the UNIX user number in hexadecimal of the last user to update this item.	hdr.user
2 PIB	D3 PIB (in hexadecimal) of the last user to update this item. This field is undefined for non-D3 drivers.	hdr.pib
3 Time/date	Hexadecimal representation of the number of seconds elapsed since 12:00 AM December 31, 1967 and the time the item was last updated.	hdr.date and hdr.time
4 Permissions	Hexadecimal number representing the permissions on the item. This currently only applies to non-D3 items.	N/A
5 GroupID	Group ID (in hexadecimal). Currently used only by the UNIX driver, but may be used by other drivers in the future.	N/A
6 - 10	Reserved	N/A
11	File type: d directory b block special file c character special file m multiplexor file l symbolic link p fifo - regular file ? unknown file type	hdr:unix:type
12	Size in decimal.	hdr:unix:bytes
13	Mode in octal.	hdr:unix:omode
14	Mode in text format (-rwxrwxrwx).	hdr:unix:mode
15	User-ID in decimal.	hdr:unix:uid
16	User-ID name.	hdr:unix:user
17	Group ID in decimal.	hdr:unix:gid
18	Group ID name.	hdr:unix:group
19	Creation date in decimal.	hdr:unix:cdate
20	Creation time in decimal.	hdr:unix:ctime
21	Modification date in decimal.	hdr:unix:mdate
22	Modification time in decimal.	hdr:unix:mtime
23	Access date in decimal.	hdr:unix:adate
24	Access time in decimal.	hdr:unix:atime

Q-pointer format

The format of the header Q-pointer is:

file.name
	001	Q
	002
	003	`hdr`:`filename`

where

hdr	Name of the hdr host in the dm,hosts, file.
filename	Name of the target file to examine. This can be a local D3 file (assuming the Y correlative has been added to the D-pointer), or a remote file (UNIX or MS-DOS).

The file can also be opened by pre-pending the file name with the string "hdr:".

Warning: Because the hdr: driver is read-only, it does not make sense to create a QS-pointer to it (to attempt to save the header data). Any attempt to do this will have no effect upon a restore. Note that it is not necessary to save header information since it is implicitly saved and restored using the save and restore utilities. Header information is not recorded on a t-dump since the succeeding t-load is considered to be a batch of new updates which change the header information in a driver-specific manner. Note that updates performed to a file from a remote site will always show the updated user as dm.

Header files

Raw attribute definitions

Q-pointer format

See also