41: What's the significance of the alpha mark (ᵀ) prefix on catalog 2 entries?

[hth]

(01-19-2020 03:52 PM)rprosperi Wrote:  You can easily copy FOCAL programs in ROM (in a module) to user RAM by simply using the COPY command. Go to the end of RAM (i.e. [GTO] [.] [.]), put the FOCAL program name in Alpha ([Alpha] [T] [V] [M] [Alpha]) then XEQ "COPY". You can then modify this copy of the program, save it to extended memory etc.

Just to be picky. You do not need (and probably do not want) to press GTO .. before doing COPY. The reason is that COPY converts the permanent .END. to an ordinary END and then appends the copied program. Thus, if you have a normal END after the last program (created by pressing GTO ..), you will get double ENDs.

Also COPY does not take it argument from Alpha, you are expected to press XEQ "COPY" [Alpha] name [Alpha].

This is all because COPY is part of the mainframe (HP-41 original firmware) and it does not contain any code to take a name from Alpha. Such routines were introduced in the Extended Functions module and the HP-IL module.

Apart from this particular case, it is (as mentioned) a good idea to use GTO .. to ensure that a program is not replaced when reading from some mass storage. There are usually two routines and the usual read-a-program from mass storage will replace the last program, which is protected by the GTO .. that creates an invisible/empty last program (if such does not already exist).

COPY is just different from the rest.