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Y2K38 Watch Starts Saturday
Jon Masters writes "I just wanted to remind everyone that Saturday, January 19th 2008 will mark the beginning of the 30-year countdown to the Y2K38 bug, when Unix time will overflow 32 bits. Some 30-year loan calculation software might start having problems with this over the weekend."
Older flavours of Unix will wrap-around on 32 bit int. More modern systems use time_t instead of int and may or may not be affected by the problem. time_t can be unsigend (which gives another 68 years) or long long int/long long unsigned (which are both 64 bit long). In any case, fixing the basis library and recompileing is enough for properly implemented software.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
> VMS has been Y10K-compliant for over a decade.
.5 changed when the day starts. Astronomers had considered it more
It's much better than that. It's mostly DCL that has the year 9999 issue. For those of you who like history lessons and how to design real operating systems (and customer support, back when it actually existed), read this article:
38 Why Is Wednesday November 17, 1858 The Base Time For VAX/VMS?
COMPONENT: SYSTEM TIME OP/SYS: VMS, Version 4.n
LAST TECHNICAL REVIEW: 06-APR-1988
SOURCE: Customer Support Center/Colorado Springs
QUESTION:
Why is Wednesday, November 17, 1858 the base time for VAX/VMS?
ANSWER:
November 17, 1858 is the base of the Modified Julian Day system.
The original Julian Day (JD) is used by astronomers and expressed in days
since noon January 1, 4713 B.C. This measure of time was introduced by
Joseph Scaliger in the 16th century. It is named in honor of his father,
Julius Caesar Scaliger (note that this Julian Day is different from the
Julian calendar named for the Roman Emperor Julius Caesar!).
Why 4713 BC? Scaliger traced three time cycles and found that they were
all in the first year of their cyle in 4713 B.C. The three cycles are 15,
19, and 28 years long. By multiplying these three numbers (15 * 19 * 28
= 7980), he was able to represent any date from 4713 B.C. through 3267 A.D.
The starting year was before any historical event known to him. In fact,
the Jewish calendar marks the start of the world as 3761 B.C. Today his
numbering scheme is still used by astronomers to avoid the difficulties of
converting the months of different calendars in use during different eras.
So why 1858? The Julian Day 2,400,000 just happens to be November 17, 1858.
The Modified Julian Day uses the following formula:
MJD = JD - 2,400,000.5
The
convenient to have their day start at noon so that nighttime observation times
fall in the middle. But they changed to conform to the commercial day.
The Modified Julian Day was adopted by the Smithsonian Astrophysical Obser-
vatory (SAO) in 1957 for satellite tracking. SAO started tracking satellites
with an 8K (non-virtual) 36-bit IBM 704 computer in 1957, when Sputnik was
launched. The Julian day was 2,435,839 on January 1, 1957. This is
11,225,377 in octal notation, which was too big to fit into an 18-bit field
(half of its standard 36-bit word). And, with only 8K of memory, no one
wanted to waste the 14 bits left over by keeping the Julian Day in its own
36-bit word. However, they also needed to track hours and minutes, for which
18 bits gave enough accuracy. So, they decided to keep the number of days in
the left 18 bits and the hours and minutes in the right 18 bits of a word.
Eighteen bits would allow the Modified Julian Day (the SAO day) to grow as
large as 262,143 ((2 ** 18) - 1). From Nov. 17, 1858, this allowed for seven
centuries. Using only 17 bits, the date could possibly grow only as large as
131,071, but this still covers 3 centuries, as well as leaving the possibility
of representing negative time. The year 1858 preceded the oldest star catalog
in use at SAO, which also avoided having to use negative time in any of the
satellite tracking calculations.
This base time of Nov. 17, 1858 has since been used by TOPS-10, TOPS-20, and
VAX/VMS. Given this base date, the 100 nanosecond granularity implemented
within VAX/VMS, and the 63-bit absolute time representation (the sign bit must
be clear), VMS should have no trouble with time until:
31-JUL-31086 02:48:05.47
At this time, all clocks and time-keeping operations within VMS will suddenly
stop, as system time values go negative.
Note that all time display and manipulation routines within VMS allow for
only 4 digits within the 'YEAR' field. We expect this to be corrected in
a future release of VAX/VMS sometime prior to 31-DEC-9999.
Not "real binary"? WTF are you talking about? It's either binary or it's not. And it's binary.
As for your poorly-made argument that computers use words with certain widths, just because you've never used a computer where CHAR_BIT != 8 doesn't mean they don't exist.
It's always a long day... 86400 doesn't fit into a short.
#!/usr/bin/perl
/1901$/) {
# (or wherever your camel lives)
#Copyleft (just joking!) Georgie http://folk.uio.no/georgios
use POSIX;
use strict;
$ENV{'TZ'} = "GMT";
# GMT for preference
print "And the transition will be like...\n";
for (my $clock = 2147483646; $clock < 2147483650; $clock++)
{
print ctime($clock);
}
chomp(my $conclusion=ctime(2147483650));
if ( $conclusion=~
print "Which means that you are bugged by 32 bits. We have 64 bit processors and structures now you know!\n";} else {
print "You will survive for now. Go and get a beer. \n";}
Lack of coverage and donations? I would agree that at least coverage wise, the tsunami did not grab the nation the same way 9/11 did, but looking at the money donated is another story.
First I would encourage you to look at this:
http://en.wikipedia.org/wiki/Humanitarian_response_to_the_2004_Indian_Ocean_earthquake#List_of_Donors
The United States government donated nearly one billion dollars and another 1.9 billion came from its citizens and NGOs. That's nearly 3 billion dollars total. A total of 10 billion dollars was given to relief from around the world.
Granted, that comes to around 0.0026% of our GDP (someone correct me if I'm reading that wrong, permilles aren't my strong suit), but it's still a massive out pouring of money if you ask me.
Reviewing just the first hour of video games.
It's "Number of seconds since midnight (0:00:00) January 1st 1970". Which in a SIGNED 32-bit number, overflows into negative in 2038.
If they'd used an unsigned 32-bit number, then they would have had dates up to 2106 covered. Unfortunately whoever invented these timestamps chose to make them use signed numbers, with negative numbers being allowed on some systems (representing dates before 1970) and being errors on other systems (e.g. Windows)...
Fortunately 64-bit numbers can now be handled by pcs, and can be used as an extended timestamp to get a few billion years of time. Most operating systems have already been converted, it's just legacy programs that would have issues.
That and most of the Y2K problems were just display errors, not bugs in the actual calculations going on under the scenes. 2038 is much scarier and is a lot more difficult to fix. In fact the best way to fix the problem is probably to switch to a 64 bit representation of time, but thus far not too many people have made moves in that direction. Switching to 64 bits is not as easy as it might sound either, since lots of programs use timestamps and many of them make assumptions as to the size of their time fields. I do wish APIs would start to get transition structures (time_t64 or something) in place that people could start using now. If you do it early enough you can save yourself a lot of headaches down the road.
The big problem of course is that most people figure their code won't be in use in 2038 and don't care. I'll be right about retirement age by then. Crap, I just realized I'm going to be the grizzled old guy they call when this problem finally rolls around. One of those crusty old farts that knows C (just like the crusty COBOL farts that got a lot of jobs back in 1999 for a few months).
I read the internet for the articles.