SimH IBM1130 GUI appears "fixed"
jfehlinger at comcast.net
Mon May 8 14:48:24 CDT 2017
> This is an update on my attempt to run, on the SimH 1130,
> the "Lunar Landing" program featured in one of Carl Claunch's
> YouTube videos. . .
Looking at one of the sample Fortran programs in Wikipedia's
article on the 1130 -- the one that finds the roots of a quadratic
equation -- and in particular, looking at the data cards that
follow the program, adjacent triplets of numbers all strictly
formatted as sign, three digits, decimal, three digits
, i.e. FORMAT 3F8.3 , led me to wonder if the initial console
input for the "Lunar Landing" program might have equally
strict formatting requirements.
I was wrong earlier about the human-readable main program
only handing console I/O -- it does in fact output the initial
console message, but it also does the output to the lineprinter
(and the logical unit for those WRITES is held in a
variable "IOUT" that's also being passed to ORBIT, which suggests
I might want to revisit using the DMS configured for 1403 printer,
by changing the DATA statement in the main program that initializes
"IOUT"). And it is ORBIT subroutine that's prompting on the console
for "ANGLE" and "VELOCITY" (ORBIT gets a logical unit number
for the READs passed as argument "IN"). I can't examine the FORMAT statements
in ORBIT for reading ANGLE and VELOCITY, since I don't have source
code for that piece of the program, but a big clue is that the
field widths for the values of "INCREMENTAL VELOCITY" and "INJECTION ANGLE"
that come out on the lineprinter show up as 11 characters wide on the
lineprinter output (even when the values are junk), and there are F11.0 and F11.3
formats in the code.
So instead of entering, for example, "10" and "10000" on the console,
I tried entering "0000000010." and "0000010000."
And that worked!
At any rate, I now see "INCREMENTAL VELOCITY" and "INJECTION ANGLE"
being reflected on the lineprinter output as the same
numbers as I entered on the console, and I'm actually getting
something that looks like a trajectory plot. It isn't exactly
heading the right way, but actually learning to play the game
will come later. ;->
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