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     TP(5)                                                       TP(5)

     NAME
          tp - DEC/mag tape formats

     DESCRIPTION
          The command tp dumps files to and extracts files from DEC-
          tape 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 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 directory; 8 entries per block; 64 bytes per
          entry.  Each entry has the following 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 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
          filsys(5), tp(1)

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