[Vm-dev] Re: [Pharo-project] who can have a look at Issue 5913: Remove Squeak epoch

David T. Lewis lewis at mail.msen.com
Wed Jun 20 01:29:26 UTC 2012


On Tue, Jun 19, 2012 at 03:32:47PM -0700, Eliot Miranda wrote:
>  
> On Tue, Jun 19, 2012 at 1:50 PM, Igor Stasenko <siguctua at gmail.com> wrote:
> 
> > IMO epoch starting is completely orthogonal to timezone bug which
> > should simply fixed.
> > If you define epoch time as 1 jan 1970 (or any other date you prefer)
> > but still will mess up with timezones, it won't change anything isn't?
> >

Absolutely right.

> 
> +1.  In Cog the VM has a 64-bit microsecond clock which is available both
> as microseconds from 1901 UTC and in local time.   This is a great basis as
> it eliminates millisecond clock rollover issues (every 49 days?), lasts for
> > 50,000 years, and needs only the one primitive to answerUTC in up to
> microsecond resolution, fully synchronised.  VW has been using such a basis
> for about a decade.  If we could add these time primtiievs to the
> Interpreter IMO we'd have a much better basis for time.
> 

Eliot,

Could I ask you to please take a second look at primitiveUtcWithOffset?
This has been in trunk VMMaker with platform support for Windows/Unix/Mac
for a couple of years now, and the background and discussion is on Mantis
at http://bugs.squeak.org/view.php?id=7458.

The underlying platform call is ioUtcWithOffset(&clock, &offset) which
could presumably be adapted to support your Cog primitives. Would this make
sense?

Dave



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