PC(IV)                      10/15/73                       PC(IV)


     pc  -  PC-11 paper tape reader/punch


     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.