TP(5)								File Formats Manual							     TP(5)

NAME

       tp - DEC/mag tape formats

DESCRIPTION

       Tp  dumps  files  to and extracts files from DECtape and magtape.  The formats of these tapes are the same except that magtapes have larger
       directories.

       Block zero contains a copy of a stand-alone bootstrap program.  See reboot(8).

       Blocks 1 through 24 for DECtape (1 through 62 for magtape) contain a directory of the tape.  There are  192  (resp.  496)  entries  in  the
       directory; 8 entries per block; 64 bytes per entry.  Each entry has the following format:

	      struct {
		      char	      pathname[32];
		      unsigned short  mode;
		      char	      uid;
		      char	      gid;
		      char	      unused1;
		      char	      size[3];
		      long	      modtime;
		      unsigned short  tapeaddr;
		      char	      unused2[16];
		      unsigned short  checksum;
	      };

       The path name entry is the path name of the file when put on the tape.  If the pathname starts with a zero word, the entry is empty.  It is
       at most 32 bytes long and ends in a null byte.  Mode, uid, gid, size and time modified are the same as described under  i-nodes	(see  file
       system fs(5)).  The tape address is the tape block number of the start of the contents of the file.  Every file starts on a block boundary.
       The file occupies (size+511)/512 blocks of continuous tape.  The checksum entry has a value such that the sum of the 32 words of the direc-
       tory entry is zero.

       Blocks above 25 (resp. 63) are available for file storage.

       A fake entry has a size of zero.

SEE ALSO

       fs(5), tp(1)

BUGS

       The pathname, uid, gid, and size fields are too small.

7th Edition							   May 15, 1985 							     TP(5)