A bit pf trivia ...
Long ago and far away, I worked at Link Flight Simulation of the
Singer Company; we ran MVS/SP on an IBM 4341. There, on the week
of 8 June 1984, an operator blew the Julian date when doing an IPL
by flipping two digits. This jumped the date forward ~ 3 months
and THAT caused the tape library scratch processing to have a
field day and threaten to wipe out good chunk of our tape
library.? (The librarians caught it promptly, thank goodness.)
I know the week because on that date I cranked out a simple
program that was started immediately after IPL and displayed on
the console a non-scrollable line similar to:
@LDCTODAY: Monday, 25 July
2022 (22.206)
This of course made it easy for the operator to promptly see the
error of their ways.
Because I'm prone to not check the time when I IPL MVS 3.8 (after
all it is slaved is to the NTP-controlled Hercules host clock
except for the timezone), I recently played with the program and
its underlying date routine to expand the output to report the
time and timezone, and as a bonus I tossed in a second message
with the GMT date and time:
@LDCTODAY: Monday, 25
July 2022 (22.206)? 9:36:19 AM -0700
@ Monday, 25 July 2022 (22.206)? 4:36:18 PM GMT
The times sources are generated by the OS TIME
macro invoked twice back-to-back:
???????? TIME?
DEC,ZONE=LT???????? Get current local time ...??????? ?
???? ST???
R0,LCLTIME??????????????????????????????????????????? ?
???? ST???
R1,LCLDATE??????????????????????????????????????????? ?
???? SPACE
1???????????????????????????????????????????????????? ?
???? TIME? DEC,ZONE=GMT??????? ... also get current GMT time
... ?
???? ST???
R0,GMTTIME??????????????????????????????????????????? ?
???? ST??? R1,GMTDATE????
Now knowing you did not look closely at the program output, back
up and look at it carefully.
Like how time flows backwards?? My uninformed guess is a truncate
issue deep in MVS with the conversion from timer units to
seconds*100 and then the hundredths are dropped.
(My time working in RBOC class voice mail has taught me well: NO
lossy conversion goes unpunished.)
-ahd-
--
Drew Derbyshire
AAAAAA - American Association Against Acronym Abuse Anonymous.
