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TP(5)                         File Formats Manual                        TP(5)



NAME
       tp - DEC/mag tape formats

DESCRIPTION
       The  command tp dumps files to and extracts files from DECtape and mag-
       tape.  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
       bproc(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 direc-
       tory; 8 entries per block; 64 bytes per entry.  Each entry has the fol-
       lowing format:

              struct {
                   char pathname[32];
                   int  mode;
                   char uid;
                   char gid;
                   char unused1;
                   char size[3];
                   long modtime;
                   int  tapeaddr;
                   char unused2[16];
                   int  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
       filsys(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  directory
       entry is zero.

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

       A fake entry has a size of zero.

SEE ALSO
       filsys(5), tp(1)

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



                                                                         TP(5)