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TP(5)                         File Formats Manual                        TP(5)

       tp - DEC/mag tape formats

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

       Block  zero  contains  a  copy of a stand-alone bootstrap program.  See

       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];
                      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 directory entry is

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

       A fake entry has a size of zero.

       fs(5), tp(1)

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

                                15 January 1983                          TP(5)