[HECnet] How long has your 20 been up?

[Johnny Billquist]

On 2022-01-20 19:57, Paul Koning wrote:
> 
> 
>> On Jan 20, 2022, at 12:20 PM, Peter Lothberg <roll at stupi.com> wrote:
>>
>> GMT is solar time! (and not used...)
> 
> Not quite.  The acronym actually says that it is not solar time, it's Greenwich MEAN Time.  UTC is merely the new name for GMT, obviously adopted to keep the French from fulminating.  (It's amusing that, just like "ISO", UTC isn't an acronym; it matches neither the English nor the French initials.)

Well, again not quite. One big reason what GMT was replaced with UTC is 
because the sortof ambiguity of GMT. What is GMT? Is that the time it is 
right now at Greenwich, or the time we think it should be in Greenwich 
if we didn't have daylight saving, or if any political decision would 
change the time at Greenwich. Basically, having a physical place 
defining normal time is problematic, because that might lead you to want 
to check what the time actually is at that place, which might not be 
what you would expect.

The classical one being that Greenwich is at 1am in the summer, when it 
is 0:00 GMT.

UTC takes any such confusion away.

> On Thomas DeBellis's observation that system programmers don't understand long arithmetic, that's obviously not true for PDP-11 programmers.  (You can't deal with non-tiny disks if you don't understand this.)

Very true. :-)
Made even more painful because the PDP-11 don't have a proper add with 
carry. (No, the ADC instruction isn't really a good alternative.)

   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