22 Feb
2003
22 Feb
'03
7:42 a.m.
If you don't want to use mere programmability as
the
line between a calculator and a computer, then
One 'working definition' that is commonly used for a (digital,
electronic) computer is that it is user-programmable. That is to say the
user can write a list of instructions that are then executed
automatically.
The calculators we're considering have this feature (the HP65, IIRC, will
remember 100 'program steps' (essentially functions from the calculator
keyboard) and will then execute them. There are unconditional and
conditional branches, which means you can have loops). There were earlier
non-programmable pocket calculators, but I don't class those as computers
(even though the HP35 had the same CPU architecture as the HP65, and ran
an intenral firmware program to make it act as a calculator -- it wasn't
hardwaired logic. But it wasn't _user_ programmable).
consider display features. The TI-58, in 1978, was
the first to display letters, not just numbers. The
catch was, it could print them on a printer, but not
Hackers managed to get a few words displayed on the HP67 using
non-normallised numbers...
IIRC, the 16 values for a nybble all displayed _something_. 0-9 were
obvious, I think the letters for 'Error' were there ,and a few others.
There were some magnetic cards that did the rounds of the user clubs with
non-normalised numbers on them to display 'interesting' messages.
on its own screen. The HP-41C, in 1979, was the
first
that could display letters natively. It also had
removable storage, which third-party companies
actually sold applications on.
The TI58/TI59 took plug-in ROM modules too. And of course HP calculators
back to the HP65 could read magnetic cards. I know HP sold Program Pacs
(sic) of pre-recorded cards for these machines, I suspect 3rd parties did
too.
Yet another twist is those primitive handheld sports
games from Mattel, etc. Those debuted in the
mid-1970s. I would NOT call them PDAs, since they
only had entertainment functions, not "assistant"
functions. But if you choose to consider a calculator
as a portable computer, then why not a game too?
The difference is that the calculator is user-programmable, the game is
not. In other words, you can run games programs on the HP65 and HP67 (HP
sold a games Pac and a couple of solution books for the HP67). You can't
run mathematical programs on the game.
-tony