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bppt(5) - Unix First Edition Manual Page
11/3/71BPPT (V)

NAME binary punched paper tape format
DESCRIPTION Binary paper tape. is used to pass and store arbitraryinformation on paper tape. The format chosen has the

following features: a) no format of the data is assumed. b)check summing c) zero suppress ion

The format is as follows: Between records, NULL characters are ignored. The beginningof the tape is considered between records, thus the leader is ignored. The first non--null character specifies the type and size ofthe record. If the character is positive (1 to 177), the record is a data record consisting of that many characters.All but the last of these characters are data, the last being a checksum. The checksum is calculated such that thesum of the entire record is zero mod 256.

If the first character is negative (200--376) the record isa zero suppression record. It is identical to minus that number of zeros of data. One character of checksum followsthis negative character. It is the positive of the negative character. The special case of a record looking like a single zerocharacter suppressed (377;1) causes no data transfer, but is an end--of--file indication.
SEE_ALSO lbppt, dbppt
OWNER ken, dmr