HP50g - RESTORE - Help needed

[DavidM]

(11-08-2024 07:14 PM)brrm Wrote:  So apparently something is wrong with the underscore however I don't understand what.

The parser built-in to the calculator interprets the underscore character as a signal that you're entering a unit object, eg. something similar to 1.5_m or 9.8_m/s^2. When it "sees" :3:BU_20210211.153, there's no way to parse that into a legitimate unit object, so it throws an error.

Keeping in mind that the SD card's contents need to satisfy naming conventions for both the calculator as well as any computer/card reader you may insert the card into, it usually makes sense to have a simple (and short) name for anything stored on the card. "_" and "." have special meanings depending on the platform, so common ground for naming conventions should be considered.

If you really, really want to use that naming convention, there's a way to "trick" the calculator into building a legitimate identifier from the string "BU_20210211.153". The steps are as follows:

Code:

\<<
  @ place the untagged object name on the stack AS A STRING
  @ (note the quote marks)
  "BU_20210211.153"

  @ convert the string to an ID
  #5B15h SYSEVAL

  @ tag the ID for the SD card
  "3" \->TAG

  @ you should now be able to RESTORE the backup object
\>>

The internal routine at address #5B15h converts a given string to an ID, bypassing the parser entirely. While it can be somewhat useful (such as in this example), it can also create problems for you in unexpected ways if you happen to name an object something that would otherwise be prohibited. I would recommend using a simpler (and shorter) name for the backup object instead.