2.11BSD#431 - /usr/man/cat5/tp.0

TP(5)		    UNIX Programmer's 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 pro-
     gram.  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 con-
     tinuous tape.  The checksum entry has a value such that the
     sum of the 32 words of the directory 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.


Printed 11/26/99	  May 15, 1985				1