(04-01-2015 09:19 AM)BartDB Wrote: (01-21-2015 11:36 PM)MarkHaysHarris777 Wrote: I keyed the example from above, and I get the checksums of the original author:
LBL G
1.4
LBL C
1.4
LBL G, LN= 9, CK= D23F
LBL C, LN= 9, CK= 18BC
These are consistent, and I cannot get them to change. I do notice another thing though... there are no RTN instructions. This problem may have to do with the branching calculation offset problem (which I do see often) because it can't figure out exactly which instructions to include in the checksum?
In my coding I always use labels, keep the labels in order, and make sure the GTO XEQ instructions don't change on editing. My checksums don't change.
The other thing I am wondering about is the build date. My unit was built in late november 2014. It still shows revision 0 2007--- but I'm wondering if they have made some subtle changes reflected in the new units, but forgot to bump up the revision level. (not likely)
Another thing that may affect this is that I reserve 101 indirect memories, which changes where the program code is located, which might make a difference on how the checksum is calculated.
By the way, my equation checksums and lengths are also very consistent. I have another HP35s on order for the purpose of cross development and experimentation; maybe I can get to the bottom of it.
Sorry about the font... I'm gonna blame my browser... the editing options are apparently not cooperating for me between my browsers. Hopefully this is better.
Thanks for the heads up! Nice to meet you Mark; have a great day.
Checksums are totally useless.
Your example is nugatory and shows lack of investigation.
Checksums change depending on what other programs or equations are in the memory.
First enter another program then enter these programs again. Or save some equations in the equation list. Checksums are different.
Stating they are useful to see if you have accidently changed a program yourself is not really useful. What if you've deleted the program and need to re-enter it? Will you remember exactly what programs and equations were present when you first entered the program?
The use of checksums on other HP calculators has made it easier for others to enter them correctly - hence it being quoted e.g. this hp-32s program has checksums at the end of each label. Now see Pauli's game for the 35s Game for HP-35s, it took me a few hours to key in and no useful checksum meant several more to re-read & test.
And now the cherry on the cake: I had about 15kb of programmes and the batteries died (after leaving the calculator unattended for about 2 months). I have the listings of all these programmes, but do you really think I remember in what order I had entered them or what equations were saved at the point I had originally entered each program? Now I have 15kb of programs to re-enter that I have to spend hours to manually re-check, test etc. to ensure they're error free!!!
The bug list is quite correct - checksums are useless. And it is a bug.
I had decided not to contribute any more to this thread, however you, Bart, seem honest & so I'll add my two pennorth.
Some folks believe the Bible more than experience or science - what such folk do with authorities is clear.
Accordingly the God given operating system must be right & any argument against it futile.
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