IBM 5100 Basic Reference Manual page 26

22
Notes About MARK
• If an existing tape file is re-marked, the original information on the re-marked
file and all files following it cannot be used again.
• The MARK command must be entered character-by-character from the keyboard.
• The MARK command can be issued any time the specified tape unit is not
otherwise active.
• Tapes withCRC errors must be re-marked (reinitialized) starting with a file
preceding the CRC error. A REWIND command is generally required before
this MARK.
• You can determine the size required for a file by comparing the amount of work
area available before and after you have entered data or programs into the work
area. Note that each numeric expression requires an average of 16 storage positions
(bytes), while each character expression requires 21 storage positions less one
position for each trailing blank.
Example
A sample MARK command is as shown:
MARK 3,6,1
In this sample, six files will be marked, starting with file 1, with each file using
3,072 bytes on the tape residing in the built-in tape unit (E80).
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