Useless HP-41 observation of the day


I was looking at differences in CATALOG behavior on the 41CX vs. the earlier models. The 41CX adds CATALOG 4 (EMDIR), 5 (ALMCAT), and 6 (key assignments), and shows byte counts on ENDs in CATALOG 1.

Anyhow, I happened to notice something that I thought was broken on the 41CX, but it turns out was unchanged from the 41C and 41CV.

If you put the value 1 in a register, say register 21, you can use "CATALOG IND 21" (pressing shift for indirect) and get catalog 1.

However, if you put the value 1 in a stack register, such as X, then press "CATALOG IND ST X" (pressing shift for indirect then decimal for stack), you get catalog 3. It appears that catalog indirect from the stack always gives catalog 3, regardless of the selected stack register.


Interesting observation. To tell the truth I've got so used to the CCD catalog(s) that never use the "standard" feature.

[IND] is handled by the OS very differently from the [ST] so it's not so surprising. I realize I'm saying this to somebody who nows it much better than myself, but it's my only idea about root causes.



I am with Angel, I have been using CCD for years now so don't see the normal cat functions. Got to admit though, never IND cat functioned before!



eric - unrelated to this thread, you mentioned a report back in 2006 posting on here:

"In the Matter of Certain Portable Electronic Calculators, Investigation No. 337-TA-198"

did you ever manage to get a hold of this? i just persuaded google books to let me download a pdf of it, 12mb with all pages stored as just graphics. made for some interesting reading, i found it first while looking for info on a TI calculator chip, then traced back to your 2006 posting.


Robert & Eric,

If you have an Android Tablet, you can get it free from the Android Market in Books. I grabbed it, but it seems I have to be connected to the internet to read the book. Not sure if there's a way to download so I could read it offline. First time I grabbed a book from the marketplace, so I'll have to play around with it.

Not sure if you would be able to read it on a phone, but it's fairly easy to read on the tablet.



I got the PDF directly from the USITC web site: USITC - 337 Publications Past Years

Lots of other interesting cases there, like the one on floppy disk drives.


excellent - their copy is searchable text! :-)

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