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MNH · 05-18-2019, 11:07 PM

How do I move a variable into the hidden directory?

**rprosperi** · 05-18-2019, 11:56 PM

From the 48 FAQ

Code:

4.17.  What is the hidden directory and how do I access it?              

The "hidden directory" is a subdirectory of the HOME directory.  It is   

created on startup, and it contains variables with your alarms and       

user key configurations.    You can use the hidden directory to store    

whatever you want, however you CAN NOT ORDER the contents of this        

directory, as this causes memory loss.                                   

The name of the hidden directory is a null character, ''.  The only      

way to get a null character is to use a syseval.  You can use the        

following program to access the hidden directory:                        

         <<  HOME                            (changes to home dir)       

             #15777h               (syseval to get null character)       

             SYSEVAL                         (returns '' to stack)       

             EVAL >>                       (changes to hidden dir)       

To exit the hidden directory, use HOME or UPDIR.  This will return you   

to the HOME directory.                                                   

Also, by putting the null character as a part of your HOME custom        

directory, you can switch right into the directory by pressing the       

softkey.                                                                 

Note: The SysRPL command NULLID returns a null character to the stack;   

it is the same as doing #15777h SYSEVAL.

MNH · 05-19-2019, 01:38 AM

I accessed the hidden directory. I have a variable named HDIST in the HOME directory. I can't use right shift [MEMORY] to move HDIST. Is there a program I can write to accomplish this?

RMollov · (This post was last modified: 05-19-2019 05:50 AM by RMollov.)

(05-19-2019 01:38 AM)MNH Wrote: I accessed the hidden directory. I have a variable named HDIST in the HOME directory. I can't use right shift [MEMORY] to move HDIST. Is there a program I can write to accomplish this?

It's not clear what you are trying to achieve. It's the first time I heard of the need to use HP48's hidden directory for anything.
From your avatar I assume you are a surveyor.
"Hidden directory" is such in terms of HP48's system and not what it literally may sound like. It is not to be used by the user.

MNH · 05-19-2019, 12:23 PM

Yes, I'm a surveyor. I'm going to write some small utility-type surveying programs for my friend. I thought I might hide them in the hidden directory so they aren't inadvertently deleted. If the hidden directory is recreated on startup, why wouldn't anything I put there be deleted anyway?

pier4r · 05-19-2019, 12:43 PM

IIRC the 48 has also flash storage, that would be the best place where to put utilities that should to survive over time. Flash storage changes (add/delete data) normally don't happen often if one is not developing stuff.

RMollov · 05-19-2019, 01:13 PM

(05-19-2019 12:43 PM)pier4r Wrote: IIRC the 48 has also flash storage, that would be the best place where to put utilities that should to survive over time. Flash storage changes (add/delete data) normally don't happen often if one is not developing stuff.

Wrong, no flash on HP48.

**rprosperi** · 05-19-2019, 01:25 PM

(05-19-2019 12:23 PM)MNH Wrote: I'm going to write some small utility-type surveying programs for my friend. I thought I might hide them in the hidden directory so they aren't inadvertently deleted.

Put an extra copy of the needed programs in an extra folder at the end of the VAR chain (so less likely to even see it). If you think the user is likely to remove that too, put copies into 2 folders. If you think the user might 'accidentally' remove both, I'm afraid it's likely the user is an idiot and 'fool-proof' solutions aren't likely. Fools can be enormously clever.

RMollov · (This post was last modified: 05-19-2019 01:36 PM by RMollov.)

(05-19-2019 12:23 PM)MNH Wrote: Yes, I'm a surveyor. I'm going to write some small utility-type surveying programs for my friend. I thought I might hide them in the hidden directory so they aren't inadvertently deleted. If the hidden directory is recreated on startup, why wouldn't anything I put there be deleted anyway?

https://www.hpcalc.org/hp48/docs/faq/48faq-4.html

Startup here means after reset, crash, TTRM etc. not turning off/on the calculator. Otherwise alarms for example would be impossible to exist.

Even though it is possible to use HD to store stuff IMO it's not worth doing it. I'd rather create sub-directory to keep data in. You can do that programmatically.

Hope this helps.

Cheers,

DavidM · 05-19-2019, 02:13 PM

Using the system's hidden directory to store objects would require all programs that access them to "jump through hoops" any time the objects need to be recalled or stored. You may want to consider the use of a "var hider" instead, which would probably be easier to use (and safer) for something like you are describing. Hidden objects in the HOME directory are universally available to all programs.

One such utility can be found here. Several others can be seen by querying the same site with "var hider".

pier4r · 05-19-2019, 03:00 PM

(05-19-2019 01:13 PM)RMollov Wrote: Wrong, no flash on HP48.

Oh. then my mistake. On the wiki I read about internal memory, I was thinking it had user space too. Then the 49g+ series was a big jump in that respect.

Massimo Gnerucci · 05-19-2019, 08:30 PM

(05-19-2019 03:00 PM)pier4r Wrote:
(05-19-2019 01:13 PM)RMollov Wrote: Wrong, no flash on HP48.

Oh. then my mistake. On the wiki I read about internal memory, I was thinking it had user space too. Then the 49g+ series was a big jump in that respect.

No, the 49g (without +).

RMollov · (This post was last modified: 05-21-2019 07:47 AM by RMollov.)

(05-19-2019 08:30 PM)Massimo Gnerucci Wrote: No, the 49g (without +).

Unless it was HP48GII Smile

Joking, that one is 49...

MNH · 05-23-2019, 02:54 AM

Thanks to everyone who replied!

Han · 05-25-2019, 04:01 PM

You could create all your programs and store them in port memory. I would make two directories: one containing the actual programs, and a second that contains "wrapper" programs that basically call the routines from the first directory AS STORED IN PORT MEMORY. Then keep both directories in port memory. Use the second directory and copy it into main memory. If your friend accidentally deletes this, then you can just copy the second directory back from port memory into main memory. The main programs, however, will always stay in the first directory and never be visible to anyone except the "wrapper" programs since it is generally harder to access port memory.