Hewlett Packard 9100A Announcement
Hewlett Packard's Measure Magazine, March, 1968

Hewlett Packard's news release announcing the HP 9100A calculator. The announcement was formally made on March 11, 1968, at New York's Waldorf-Astoria Hotel, with HP's Chairman of the Board, and Founder, David Packard, addressing a packed audience of members of the press from all over the world. Prior to this formal announcement of HP's revolutionary electronic calculator that blurred the lines between a calculator and a small computer, rumors had abounded about the secret calculator project that HP had been working on for over two years.

The HP 9100A changed the world of the high-end electronic calculator, completely blowing away existing high-end programmable calculators from Wang Laboratories, Olivetti, IME, and Mathatronics; along with a number of lower-end programmables from Monroe, Wyle Laboratories, Nippon Calculating Machine Co.(a.k.a. Busicom) and Casio.

The 9100A set the standard for a desktop programmable electronic calculating device through the mid-1970's, with only Computer Design Corporation's (sold both under the Monroe and Compucorp brand names, among others) high-end large-scale MOS integrated circuit-based machines based on its HTL chip set coming closest, despite the fact that the HP machine didn't have any digital integrated circuits in it. All of the 9100A's digital circuitry was implemented with discrete transistors, diodes, resistors, and capacitors.

Only once MOS-LSI integrated circuits implementing complex microcoded CPU architectures, along with MOS Random Access (RAM) and Read-Only (ROM) for storing the calculator's working registers, memory registers and user programs; such as Computer Design Corporations HTL chip set architecture, and the Tektronix 21 and 31 calculators with their complex multi-level microcode architecture derived from the earlier Cintra 909 calculator, did the capabilities of the HP 9100A start to be matched or improved upon by other calculator manufacturers. Later in the 1970's, with the advent of the microprocessor, considerably more capable desktop programmable calculators were developed by Canon, Sharp, Texas Instruments.

Despite the competition trying to nip at Hewlett Packard's heels, HP did not stand still. The 9100B came along and doubled the amount of memory available for program steps and number storage, as well as adding some useful programming capabilities. Again, this machine had no digital integrated circuits. Not long behind the 9100B was the introduction of Hewlett Packard's 9800-series, with the announcement of the 9810A, implemented with a 16-bit bit-serial CPU patterned after Hewlett Packard's successful 2116 mini-computer, made with small and medium-scale bipolar integrated circuits, coupled with MOS Random Access Memory chips (from Intel), and high density bipolar ROM made by Hewlett Packard. The 9810 was essentially an integrated circuit re-make of the 9100B, but with some features changed from being standard to optional. Not long after the 9810 was announced, two new machines in the 9800-series were introduced, both using the same four-board CPU as the 9810, but changing the display to an alphanumeric LED display, and providing an actual human-readable programming language for programming the calculators. In the case of the 9820A, it was a language called RPL, and in the case of the 9830, the BASIC computer language. These two calculators decidedly blurred the line between calculator and computer, providing computer-like capabilities in a desktop (albeit rather large) package.