
Students' Guide to Business Computing
At the next update, the 'father' is used as input, and the output is
written to a third disk known as the 'son'. In the event of a fault being
discovered it would be possible to go back to the 'father' or even the
'grandfather'.
A further method of ensuring that the correct disk is used is to write
the file serial number onto a file header record.
Output data needs to be controlled too. In particular, output which
goes outside the organization needs to be checked to ensure that it is
both correct and sensible. There are many tales of electricity and gas
board computers sending out bills for £0.00 and the ...