dp.4

UNIX v6源代码 这几乎是最经典的unix版本 unix操作系统设计和莱昂氏unix源代码分析都是用的该版

.th DP IV 8/24/73
.sh NAME
dp \*- DP-11 201 data-phone interface
.sh DESCRIPTION
The
.it dp0
file
is a 201 data-phone interface.
.it Read
and
.it write
calls
to dp0
are limited to a maximum of 512 bytes.
Each write call is sent as a single record.
Seven bits from each byte
are written along with an eighth odd parity
bit.
The sync must be user supplied.
Each read call returns characters received from a
single record.
Seven bits are returned unaltered; the eighth bit
is set if the byte was not received in odd parity.
A 10 second time out is set and a zero-byte
record is returned if nothing is received in that time.
.sh FILES
/dev/dp0
.sh "SEE ALSO"
dn (IV), gerts (III)
.sh BUGS