It had many new functions - not just the functions needed for programming. It also had a built-in device for reading and writing magnetic cards; this allowed the user to save programs (but not data) on cards for future use, and to get programs on cards from HP, from other users, or from the HP User Library.

HP sold sets of programs on particular topics, bundled together as "program pacs". The name "pac" lasted right through to the HP-41, for which a "program pac" usually meant a plug-in module.

The arrival of the HP-65 prompted Richard Nelson to set up PPC, the first club for users of HP handhelds; indeed it is possible that this was the world's first club for users of computers, as opposed to the few clubs which already existed for people who were building their own micros at the time.

Despite its many new features, the HP-65 was still very similar to the HP-35; obvious differences were the card reader, the slot to hold a card below the display (this allowed the user to write labels, on the card, for the row of keys directly below the card and the display - the row of menu keys below the HP48 screen is a modern version of the same thing), and the second slider switch; to select program or run modes.

This article is part of the WMJARTS file. This file contains a series of articles written by Wlodek Mier-Jedrzejowicz and published in DATAFILE, the journal of the HPCC. The article was reproduced with permission of the author.