Table of Contents
Advertisement
Card Reader Operations
13
When you pass an unprotected but previously recorded card through the
card reader with the HP-41C set to PRGM mode, the previous contents of
the track are lost and are replaced by the new program instructions.
Any card-writing session may be terminated by pressing
or (=
Writing Programs on Clipped (Protected) Cards
Clipping the corners off of program cards normally prevents them from
being used again for writing operations. Clipped cards can, however, be
read any number of times.
Attempting to write on a protected track (one with the corner clipped)
will result in a special message:
PROTECTED
The card will pass through the card reader and is not written. The display
will prompt for another card with RDY kk OF nn.
To write a program onto a protected track, simply set flag 14, the card
reader Overwrite Flag, before you begin the writing operation. The
Overwrite Flag remains set and allows you to write on protected tracks
until the program writing operation is completed or terminated.
Flag 14 is automatically cleared each time you turn the HP-41C on and
when any reading or writing operation is completed or terminated.
This procedure prevents you from accidentally destroying the informa-
tion on a card, but allows you to re-use cards after they have been
protected.
Writing a Private Program Card
The HP-41C and card reader can work together to provide a
security system that will prevent accidental alteration and
reproduction of important programs. Once a program is made
"private" on a card, it cannot be viewed, altered, or re-recorded
onto another card through normal operations.
To write a private program card:
1.
Select a blank, unprotected (unclipped) card.
2.
Position the HP-41C to the program you wish to make private.
(Press @8
(<] (aLpHa)name (aLpHa ] , supplying the program
name.)
Advertisement
Table of Contents
