Re: QCENTURY and other date-related system values

The machine actually supports a date range of 08/23/1928 12:03:06 (and some
number of microseconds that can differ depending on the version/release) to
05/10/2071 11:56:53 (and again some variable number of microseconds). 2053
is simply the current operating system limit. In much earlier releases the
max value was less than 2053.

And it's not so much that 1928 was an important year in computing, but that
the exact midpoint (TOD x'8000000000000000') between these dates/times (if
you use the correct microsecond values) is 01/01/2000 00:00:00.000000. :)
So Y2K was in the thoughts of IBM Rochester waaaay back when the S/38 was
being designed -- which is where this range is coming from.

On Thu, Jun 28, 2018 at 5:19 AM DrFranken <midrange@xxxxxxxxxxxx> wrote:

Just guessing here but since this is the SYSTEM time I'm guessing
someone decided there was no possible computer before 1928 or some
similar thinking. Perhaps 1928 was an important year in computing?

As to 2053 maybe IBM is saying that i 7.3 support will really truly end
in 2053 as you won't be able to set the date beyond that year! Time to
upgrade!

- Larry "DrFranken" Bolhuis

www.Frankeni.com
www.iDevCloud.com - Personal Development IBM i timeshare service.
www.iInTheCloud.com - Commercial IBM i Cloud Hosting.

On 6/28/2018 1:25 AM, John Yeung wrote:

On Thu, Jun 28, 2018 at 1:07 AM, Dan <dan27649@xxxxxxxxx> wrote:

To the best of my knowledge, QDATETIME will return a valid date all the

way

through the year 9999.

Well, the system values are all *settable*, not just gettable. So
let's say you set QDATETIME to 4018-06-28. What do you get when you
retrieve QDATE and QCENTURY?

Obviously, I'm not going to try this on any actual machine!

More to the point, any date data type with a
4-digit year will correctly support any year up to 9999. The 54-99 and
00-24 century crap only applies if you are using date data types with a
2-digit year.

I wouldn't be so sure. Why does the documentation say that the years
1928 through 2053 are supported? Why not a 100-year window? Why not
1901 through 2099?

There are sometimes other constraints besides the number of base-10
digits. I don't know if that's the case here, but I don't know that
it's not.

John Y.

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