1TP(5)                         File Formats Manual                        TP(5)
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NAME

6       tp - DEC/mag tape formats
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DESCRIPTION

9       Tp  dumps  files  to  and extracts files from DECtape and magtape.  The
10       formats of these tapes are the same except that  magtapes  have  larger
11       directories.
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13       Block  zero  contains  a  copy of a stand-alone bootstrap program.  See
14       reboot(8).
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16       Blocks 1 through 24 for DECtape (1 through 62 for  magtape)  contain  a
17       directory of the tape.  There are 192 (resp. 496) entries in the direc‐
18       tory; 8 entries per block; 64 bytes per entry.  Each entry has the fol‐
19       lowing format:
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21              struct {
22                      char            pathname[32];
23                      unsigned short  mode;
24                      char            uid;
25                      char            gid;
26                      char            unused1;
27                      char            size[3];
28                      long            modtime;
29                      unsigned short  tapeaddr;
30                      char            unused2[16];
31                      unsigned short  checksum;
32              };
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34       The  path name entry is the path name of the file when put on the tape.
35       If the pathname starts with a zero word, the entry is empty.  It is  at
36       most  32  bytes long and ends in a null byte.  Mode, uid, gid, size and
37       time modified are the same as described under i-nodes (see file  system
38       fs(5)).   The tape address is the tape block number of the start of the
39       contents of the file.  Every file starts on a block boundary.  The file
40       occupies  (size+511)/512 blocks of continuous tape.  The checksum entry
41       has a value such that the sum of the 32 words of the directory entry is
42       zero.
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44       Blocks above 25 (resp. 63) are available for file storage.
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46       A fake entry has a size of zero.
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SEE ALSO

49       fs(5), tp(1)
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BUGS

52       The pathname, uid, gid, and size fields are too small.
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567th Edition                      May 15, 1985                            TP(5)