What makes "FOCAL" FOCAL?

[Sylvain Cote]

The HP-41C was an evolutionary in some aspects and also revolutionary in others.

On the RPN side, the HP-41C was mainly an evolution with some twist.

The user experience related to the language changed drastically.
Previous models stored key codes in RAM and the interpreter had to find the desired function through a lookup table using the key code.
On the HP-41C, the uses of alpha introduced the possibility to store the table entry directly in RAM and do a reverse lookup to display the function name using the table entry.

The simple fact of displaying the name and not specific key codes allowed the RPN language to finally exist by itself.
Also, for the first time the RPN language became extensible through XROM facility instead of pre-defined finite set of functions.

What put the HP-41 apart from all the other hand-held calculators before it was its I/O capability.
This allowed HP & third parties to create a whole set of modules, peripherals and interfaces who were integrated seamlessly in the calculator through its I/O ports and XROM facility.
It also changed the nature of the beast making it not just a calculator, but also one of the first truly low power battery operated personal computer.

[Orome]

(04-14-2020 05:40 PM)Sylvain Cote Wrote:  The HP-41C was an evolutionary in some aspects and also revolutionary in others.

On the RPN side, the HP-41C was mainly an evolution with some twist...

So really what the 41 represents is a powerful, flexible, and above all, extensible programming platform; but the language was pretty much the same as its ancestors' (plus the usability enhancments of alphanumerics provided by the platform).

[Sylvain Cote]

(04-14-2020 06:50 PM)Orome Wrote:  So really what the 41 represents is a powerful, flexible, and above all, extensible programming platform; but the language was pretty much the same as its ancestors' (plus the usability enhancments of alphanumerics provided by the platform).

Yeah, that is basically it.

Almost everything HP did after the initial HP-35 was evolution between generations, in both hardware and software. (which make perfect sense IMHO)

For the languages ...

• RPN is represented as key codes in Classic, Woodstock, Topcat, Spice/Spike, Sting (19C) & Voyager series
• RPN is represented as function names in Nut & Pioneer (RPN models) series
• BASIC is used in 75C/D & 71B
• FORTH is available for 75C/D & 71B
• AOL is represented as key codes in some Pioneer models or as solver formula in some other Pioneer models
• RPL is used in Champion & 48/49/50 series
• PPL is used in Prime & others (38G? not sure of this one)
  

edit: added AOL / Algebraic calculators

[Orome]

(04-14-2020 08:16 PM)Sylvain Cote Wrote:  

(04-14-2020 06:50 PM)Orome Wrote:  So really what the 41 represents is a powerful, flexible, and above all, extensible programming platform; but the language was pretty much the same as its ancestors' (plus the usability enhancments of alphanumerics provided by the platform).

Yeah, that is basically it.

For the languages ...

• RPN is represented as key codes in Classic, Woodstock, Topcat, Spice/Spike, Sting (19C) & Voyager series
• RPN is represented as function names in Nut & Pioneer (RPN models) series
• BASIC is used in 75C/D & 71B
• FORTH is available for 75C/D & 71B
• RPL is used in Champion & 48/49/50 series
• PPL is used in Prime & others (38G? not sure of this one)

Excellent summary!

[Sylvain Cote]

(04-14-2020 08:27 PM)Orome Wrote:  Excellent summary!

I had forgotten the algebraic models.

[Orome]

(04-14-2020 10:16 PM)Sylvain Cote Wrote:  

(04-14-2020 08:27 PM)Orome Wrote:  Excellent summary!

I had forgotten the algebraic models.

I never include them myself.

[Andres]

(04-14-2020 08:16 PM)Sylvain Cote Wrote:  

(04-14-2020 06:50 PM)Orome Wrote:  So really what the 41 represents is a powerful, flexible, and above all, extensible programming platform; but the language was pretty much the same as its ancestors' (plus the usability enhancments of alphanumerics provided by the platform).

Yeah, that is basically it.

Almost everything HP did after the initial HP-35 was evolution between generations, in both hardware and software. (which make perfect sense IMHO)

For the languages ...

• RPN is represented as key codes in Classic, Woodstock, Topcat, Spice/Spike, Sting (19C) & Voyager series
• RPN is represented as function names in Nut & Pioneer (RPN models) series
• BASIC is used in 75C/D & 71B
• FORTH is available for 75C/D & 71B
• AOL is represented as key codes in some Pioneer models or as solver formula in some other Pioneer models
• RPL is used in Champion & 48/49/50 series
• PPL is used in Prime & others (38G? not sure of this one)
  

edit: added AOL / Algebraic calculators

Excellent analysis, Sylvain!

[Garth Wilson]

(04-14-2020 02:39 PM)Orome Wrote:  

(04-14-2020 06:49 AM)mfleming Wrote:  If you are looking for differences in the programming semantics (i.e. opcodes), then I would point to the soft END as a distinguishing feature of the HP41, compared to prior models...

Can you say more about why you think of this an any different semantically from label addressing generally?

You can have local labels that are local to each program. If a label is used in another program as well, the program you're using will go to the right one. You can delete a program all at once without deleting individual steps and having to watch for when you're coming to the next program that you don't want to affect. You can also transfer programs to and from mass storage or cards or extended memory without affecting other programs. Before I had the 41, I used a TI-58c and then a 59. You could sort of have multiple programs in memory at once, but with extreme limitations that the 41 doesn't have, now particularly referring to labels and things like how you would store or load a program with magnetic cards.