|Re: Wow! After all these years, a bug in the original 15c? YES IT IS!|
Message #55 Posted by C.Ret on 20 Sept 2011, 3:56 p.m.,
in response to message #54 by Howard Owen
I have to admit that I share your point of view.
And considering that users have only discovered this issue after more than 26 years, let me think that the “corporate” decision to leave it uncorrected it was a good one.
Why, may they have spent any time and involve any resources to fix an issue that nobody will discover before several decades?
At the time, every one receives only one manual. Who can have compare two version and discover the change? A few.
During the last 30 years, how many people use a HP-15c? Many.
How many of the many user of an Hp-15c have never program it ? A majority.
But, how many of these users have program the HP-15c for something else that entering the function to be root finding, solving or integrating? A fraction.
How many people from this fraction have used HP-15c to make advance and complex program code? A bunch. Since the great advantage of the HP-15c is complex, matrix, root finding, numerical integrating, etc… It is not especially dedicated to advanced programming tool – even if it is a capable advanced unit –
From this bunch of advanced programming coders, how many have used any of the two indirect branching instruction GTO I or GSB I ? A few, since most of the problems needs conditional branching and a few algorithms need indirect branching.
From this few of indirect branching advanced program coders, how many have used branching to label (I >0 ) compare to line number (i<0)? A rare, since using label is far easier to program since you to worry about exact line counts. Correct line addressing is a serious challenge.
From this rare indirect line branching advanced program coders using I<0, how many have used GTO I compare to GSB I ? A half.
Conclusion, during the last 30 years, people who have used GSB I (with i<0) on an HP-15c in program are certainly a rare half of a few bunch from a fraction of the minority of the many HP-15c users.
I am not surprise nobody discover this issue before we have many people sharing manual, documentation and experiences on Internet, own several models and collectors, compare versions and survey serial numbers, compare original material performance with new release, play and try to use modern program paradigm on vintage systems.
A last question, just to survey and infirm/confirm my statistics:
During these last 30 years, how many of you people reading this post have already used or program the GSB I instruction with I<0 on an Hp-15C ?
Please! Hand up ! Don’t be scared !