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LIF File Types: HP 41, 71, 75, series 80
09-26-2014, 10:03 PM
Post: #7
RE: LIF File Types: HP 41, 71, 75, series 80
Hi Bob,
thank you for your support; the easiest way to build up a collection is to post file type information here. After the accumulation of new file types will slow down and we come near to completion, I will build a text file from it and send it to Ansgar. Finally the list should be available for download at the museum; what could be the appropriate location for that?
Below I will start the list with the HP 71b file types described in Appendix D of th IL-Manual Dave pointed us to.
Hi Dave, the problem with the implementation bytes ( I will stick to that term from now on; I called it "General Purpose field" ) is resolvable, I think.
But at first I would like to give my view to your doubts about the general benefit of a tool that allows us to exchange files between DOS file system and LIF image.
You mentioned that it is convenient to extract an HP 71 ROM image to DOS for use with an emulator. Of course the same holds true for HP 41 rom files, not only for use in an emulator, but also for upload to a 41CL via serial interface, for example.
But these special cases are beside the point. I want to have a tool that allows me to compose my personal LIF files in a convenient way, in a graphical environment (Windows). For example I want to combine HP 41C programs that share a certain aspect in one LIF image. Some of the files may reside in the swap disks, some may have been written by myself, another one might have been sent to me as an email attachment. I don't want a whole LIF image for every single file.
And now about the lost information: the implementation bytes.
One way to preserve that information was to add a LIF header to the file.
Another way ( see series80 web site ) was to add the information as a leader ( prefix bytes ) to the file itself, a very similar solution.
I propose a different approach: Addition of the implementation bytes to the file name.
Exactly that is already done with the file type ( in HPDir), it is appended in the form ".#FFFF", where FFFF is a four digit hex number denoting the file type.
Why shouldn't we expand that mechanism and build the file name that way:
"AAAAAAAAAA#XXXXXX.#FFFF", where the A's build the 10 character file name, and the 6 hex digits "XXXXXX" denote the implementation bytes?
Maybe that doesn't look nice as a file name in a list, but HPDir could suppress the additional information when displaying file names, of course.
Now we could freely copy and move files between LIF images (which show up as folders in HPDir) without loss of any information.
By the way, the next step in realizing the perfect LIF tool could be: Implementation of viewers for (the most common) file types. A double click on an HP 71 Basic File should automatically start something like "TRANSFORM INTO TEXT" (by invoking HP71Emu, for example, not necessary to reinvent the wheel ) and show the corresponding text file.

The main file types for the HP 71B:
some file types come in different flavors, due to additional flags for PRIVATE and SECURED; I denote these with _S, _P or _SP respectively.

File Type (hex) Name Description
0001 TEXT
E0D0 SDATA HP 41 - file type
E0F1 DATA_S secured DATA file
E204 BIN71 binary program
E205 BIN71_S binary prog. secured
E206 BIN71_P binary prog. private
E207 BIN71_SP bin. prog. secured private
E208 LEX71
E209 LEX71_S
E20C KEY71
E20D KEY71_S
E214 BAS71
E215 BAS71_S
E216 BAS71_P
E217 BAS71_SP

Dave told us that the implementation bytes for the HP 71 binary files ( LEX and BIN, I suppose ) are the file size in nibbles.
Does anyone know whether the other file types listed above make use of the implementation bytes?
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RE: LIF File Types: HP 41, 71, 75, series 80 - Michael Fehlhammer - 09-26-2014 10:03 PM

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