CORRECT 21/02/12
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A.J. HERBERT

PURPOSE

This is a utility program for correcting errors that arise when using
the GNT 4604 paper tape punch on a PC, namely occasional mispunches
and dropped rows.

FORM OF DISTRIBUTION

The program is distributed as a sum-checked binary for loading under
initial instructions.

OPERATING INSTRUCTIONS

The program should be triggered at 8 to read in editing commands from
the teletype.  Usually these commands will have been copied from a run
of the COMPARE command in the Elliott 900 Simulator, comparing a
master tape against a suspect copy produced by the GNT 4604.

The program halts when the commands have been read.  The program
should then be retriggered at 9 whereupon it will read in the suspect
tape and punch a corrected version.  The reading process is buffered
to reduce wear on the paper tape reader, but still requires a reader
capable of stopping on a single character.

COMMAND FORMAT

The commands consist of pairs of integers.  The first integer of each
pair is a position at which an edit is required.  The position is
relative to the first non-zero row in the master tape, which is given
position 0.  The second integer is an edit command.  If the value is
less than 256, the value should be inserted as an additional row at
the specified position.  If the value is greater than or equal to 512
then the value less 256 should be substituted for the input row at the
specified position.  A negative position terminates the list, and the
"edit" following gives a count of the number of rows to be read
following the initial blanks of the suspect copy.


ERRORS

Error "COR 1" will be given if too many commands (more than 10) are
input.

Error "COR 2" will be given if the input tape size specified is less
than one row.

FILES

CORRECT.DAT: script to build and test the program.  CORRECT.BIN:
binary version of the program.  CORRECT.TXT: this file.