why was the wand made?

[vassilisprevelakis]

I believe that the first use of barcodes for program delivery was introduced by BYTE magazine in the 70s. They even trademarked the name PAPERBYTE.

Although the format was described in various BYTE magazines, there is a PAPERBYTE publication by Ken Budnick (https://archive.org/details/Bar-Code-Loa...dnick-1977) which describes the format and provides sample code.

So it was quite logical for HP to use this format (with modifications) for distributing HP-41 programs and data. After all the HP-41 memory was fairly limited, so one could fit barcode for a program in a few pages.

Although offset printing was expensive, I remember in the early 80s I was using the multistrike capability of a Diablo daisywheel printer (with a TITAN 10 metal wheel) to print barcodes.
The Diablo was kept in the machine room and we would submit "print jobs" to be printed on that printer. When printing barcodes, the Diablo would change from the clack clack clack of normal printing to a machine gun rattle that would scare the machine room operators into thinking that it had gone crazy and turn it off. So I would submit sample output with my "print job" to make sure that the operators knew what to expect.

Later, of course, laser printers made barcode production accessible to more people (i.e. ones who could get access to a company or university laser printer).

In the mid-80s, Acorn User, a magazine dedicated to the BBC microcomputer (in the UK) was distributing programs in barcode format. These could be read by a barcode reader they were selling, but I modified my wand to read these programs. I opened the module and disconnected the wand from the module and then connected them together again with DB-9 connectors. This allowed me to connect the wand part to my BBC microcomputer and write a program to read the Acorn User bar codes.

Fun fact: The BBC micro keyboard had a CAPS LOCK led which could be turned on or off under program control. So by pulsing this LED I could trick the wand into loading programs into the HP-41C. I remember using Blu Tack to keep the wand over the LED.

Vassilis
http://www.series80.org