Re: The first HP-41C?



#2

Yep, yours is a month older than mine. Dave posts the earliest he's aware of, so you need to let him know. The last 5 digits are sequence within the week's run, so without a table of highest-known sequence numbers you can't conclude anything about the relative production. If week 26 was indeed the first week ofd production it may have even started mid-week.

As a check on whether it's internally an early 41C, it should have all 9 bugs, and should have the gold balls for the (never-built) AC adapter.


#3

Just about these famous 9 bugs.

Is it possible to have complete informations about these 9 bugs and about which have been fixed (and when !!!).

Because my HP41C has a serial number 1942Axxxxx and I would like to know if it as some of these bugs (and if it has some bugs fixed later it was produced !!!!).

Thanks

PS: please excuse my bad english.


#4

From Craig A. Finseth's HPDATAbase (An excellent colletor's resource):

http://www.finseth.com/~fin/hpdata/hp41c.html

Bugs/ROM-Versions::

#1: Early machines did not save X into L when \GS+ and \GS- were done.

#2: Early machines allowed RCL IND nn and STO IND nn when nn was
outside the memory range.

#3: Early machines allowed SF,CF,FS?C, and FC?C IND nn with nn any
number (but not a stack register) 0 to 55.

#4: Early models compute the SIN of small angles incorrectly.

#5: CLP would only clear 1089 program lines.

#6: -67A/-97A prorams that contain combinations of number entry, EEX,
and CHS do not translate correctly. Example:

EEX CHS 7 CHS 5

translates to

E-7-5

instead of

1E-7 -5

#7: The second nybble of the seventh byte of Alpha is copies along
with the first six bytes during an ASTO.

#8: Early machines do not decompile programs if they are turned off
during PRGM mode.

#9: Executing CAT 1 while in PRGM mode, then interrupting it with R/S
causes step labelling oddities.

#10: If flag 25 is set and MEAN or SDEV causes an overflow, some flags
can be altered.

#11 (CW1): If a program at the end of CAT 1 is replaced or deleted, a
return to that program will return into the new program or off-program
memory.

#12: On early models, the function LN(1+X) gives wrong answers for
values of X between -.9990234374 and -1.00.

#13: On early models, the operation (.1)^-43 gives an answer of
9.999999999E42 instead of 1E43.

ROM Versions:

version date codes comments
DDE 1926-1940 all bugs
FDE 1936-1952 #3 removed
FEE 1951-2034 #1,#2,#4 removed
GFF 2035-84?? #5,#7,#8 removed, first -41CV version
HFF 84??-present current -41CV version
NFL 2329-present current -41CX version


#5

A bit of a commentary on the bugs:

#1: Early machines did not save X into L when \GS+ and \GS- were done.

This was just a bug, and a pain!

#2: Early machines allowed RCL IND nn and STO IND nn when nn was outside the memory range.

These allowed the user to reach into program memory and change things (it allowed the birth of synthetic programming on the HP41C)

#3: Early machines allowed SF,CF,FS?C, and FC?C IND nn with nn any number (but not a stack register) 0 to 55.

The first bug to be fixed. So to check for all bugs do: 49, STO 01, SF IND 01. On an allbugs calculator the BAT flag is displayed, on a non bug 3 calculator you get NONEXISTANT.

#4: Early models compute the SIN of small angles incorrectly.

Just a pain.

#5: CLP would only clear 1089 program lines.

...and even less with the printer connected (224 steps from memory)

#6: -67A/-97A prorams that contain combinations of number entry, EEX, and CHS do not translate correctly. Example:

Also a problem that pointed the way to synthetic programming.

#7: The second nybble of the seventh byte of Alpha is copies along with the first six bytes during an ASTO.

Horrible if it bites you!

#8: Early machines do not decompile programs if they are turned off during PRGM mode.

Amusing bug - and not fixed until quite late (2035)

#9: Executing CAT 1 while in PRGM mode, then interrupting it with R/S causes step labelling oddities.

Provides the "modern" way to bootstrap byte jumper or other synthetic key assignments. Also allows you to un-private programs :-)

#10: If flag 25 is set and MEAN or SDEV causes an overflow, some flags can be altered.

Odd!

#11 (CW1): If a program at the end of CAT 1 is replaced or deleted, a return to that program will return into the new program or off-program memory.

Fun! Almost not a bug IMHO, rather a caution for people who want to remove programs that are still effectively running.

#12: On early models, the function LN(1+X) gives wrong answers for values of X between -.9990234374 and -1.00.

Ooooh! But not the usual range in which you would use this function.

#13: On early models, the operation (.1)^-43 gives an answer of 9.999999999E42 instead of 1E43.

Ooops :-)


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