HP15c CE: 8x8 equation system

[Steve Simpkin]

(05-14-2023 09:26 PM)jonmoore Wrote:  …
Being totally selfish, whilst also donning my fave rose tinted glasses, those HP pocket computers led to RPL,and HP certainly knew their market on that front (if we forget the 28C ever existed with its piffling 1-2kb of user program.RAM).

Regarding the HP-28C. Around 1986 Bill Wickes proposed designing a new advanced graphing scientific calculator with algebra capabilities. At the time there was no budget available to develop an entirely new calculator like Bill wanted to do. Bill's choice was to either use the existing hardware of the HP-18C with its limited 2K of RAM (along with more ROM) or gamble and wait sometime in the future to see if management would approve a development budget for the hardware he really wanted to develop (basically the HP-48SX). No one at HP was certain how much of a market there was for an advanced scientific graphing calculator with algebra capabilities. HP allowed the team to test the marketplace using the already developed HP-18C hardware. When the HP-28C turned out to be a huge hit, they approved the budget needed for the HP-28S and then for the HP-48SX.

I am sure some people found the 1.6 KB of user RAM quite limiting, particularly when using its advanced algebra/calculus applications. Coming from a HP-11C, it was a huge step up for me. Even with its meager memory, I was able to write dozens of small utility programs that I used when designing new analog/digital circuit boards. I also used the Solver a lot.

In any event, it wasn't that HP deliberately decided to limit the amount of memory available in the HP-28C, it was more that they decided to build it at all. The HP-28C became a pivotal stepping stone for the models that came after it.