PC(IV) 10/15/73 PC(IV)
NAME
pc - PC-11 paper tape reader/punch
DESCRIPTION
Ppt refers to the PC-11 paper tape reader or punch,
depending on whether it is read or written.
When ppt is opened for writing, a 100-character leader is
punched. Thereafter each byte written is punched on the
tape. No editing of the characters is performed. When the
file is closed, a 100-character trailer is punched.
When ppt is opened for reading, the process waits until tape
is placed in the reader and the reader is on-line. Then
requests to read cause the characters read to be passed back
to the program, again without any editing. This means that
several null leader characters will usually appear at the
beginning of the file. Likewise several nulls are likely to
appear at the end. End-of-file is generated when the tape
runs out.
Seek calls for this file are meaningless.
FILES
/dev/ppt
BUGS
If both the reader and the punch are open simultaneously,
the trailer is sometimes not punched. Sometimes the reader
goes into a dead state in which it cannot be opened.