19 Jan
2022
19 Jan
'22
1 p.m.
Yeah, I love that one too.
I'm sure it will break at some point, but I have not looked at it in
quite a while, so not sure exactly what the limits are there.
Probably might break around the year 4000. And I'm sure the moon phase
calculation will eventually get out of phase.
Johnny
On 2022-01-19 04:21, Mark Matlock wrote:
Johnny,
I got to wondering, on RSX, when in the future does my favorite Easter Egg break?
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
time /roman
Januarius XVIII, Anno Domini
MMXXII XXI:XVIII
The moon is waning gibbous. Today is Tuesday.
Happy New Year,
Mark
On Jan 18, 2022, at 1:26 PM, Johnny Billquist
<bqt at softjar.se> wrote:
On 2022-01-18 20:15, Paul Koning wrote:
Ooops indeed. This is a bit of a surprising limitation in Tops-20 for me.
Neither have RSX. However, I do know that VMS have an uptime problem. Or rather a time
problem. Because of the way time is represented, everything will fail catastrophically
somewhere around the year 31000. VMS represents time as a signed quad. 100ns resolution,
and offset from 1858 (or whenever it was). Anyway, the important bit is that it is signed,
and it has to be positive.
Because negative time values are considered to be relative (delta) times. And so, when
the time actually wraps over, things will go totally bonkers in VMS.
Of course, other things will probably start causing problems long before then, like when
years start needing 5 digits...
With RSX, I am not aware of anything that will cause fatal problems. Time representation
might get a bit broken around the year 33000 or so, but I don't think anything
catastrophic will break. Years are just a 16 bit value with an offset of 1900. But very
few things even use it for anything, except printing it out. So signedness or not might
cause things to look funny depending on the code, but most software itself will not care.
Various subsystems will probably have issues long before then, like time stamps on files
will wrap, queue manager time handling will break/wrap, and of course DECnet time
representation can't deal with it. But the OS itself will probably just continue
chugging along, as will most software.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
On Jan
18, 2022, at 2:05 PM, Thomas DeBellis <tommytimesharing at gmail.com> wrote:
...
I wrote TIMET2 because I needed to know when to set a shutdown. If you don't do that
and you hit the uptime limit, then the machine simple crashes with an UP2LNG BUGHLT.
Oops. I know
that XKL fixed at least part of the uptime problem, but I don't remember what that
limit is. What are the limits for other systems?
It's not overly strange that
designers of mainframe systems, where planned shutdowns (say, for preventive maintenance)
were a regular occurrence) would overlook silly bugs like that. It feels like the sort of
thing that minicomputer software, especially real time systems, would never do. For
example, RSTS has no uptime limit.