Operating systems of the 1970s handling dates beyond the year 2000

Robert Jarratt robert.jarratt at ntlworld.com
Mon Jan 19 03:37:04 CST 2015



> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of John
Wilson
> Sent: 19 January 2015 08:05
> To: General Discussion: On-Topic and Off-Topic Posts
> Subject: Re: Operating systems of the 1970s handling dates beyond the year
> 2000
> 
> On Mon, Jan 19, 2015 at 02:07:59AM -0500, Mike Alexander wrote:
> >MTS will work ok until the original IBM TOD clock overflows in 2042.
> 
> I always liked how the March 1/1900 starting point sidestepped the
leap-year
> ugliness.
> 
> >Fixing it for 2042 will be a bigger problem if anyone who cares is
> >still around.  Since STCK is a non-privileged instruction finding and
> >fixing the problems will be challenging.
> 
> The great thing about emulation is that you can make an instruction be as
> thorny as you want, temporarily, to flush out stuff like this.
> 
> John Wilson, ETS4
> D Bit

When I tried an early date with Ultrix to make the day of the week correct
it said the date wasn't possible because it was before Ultrix was released.
I found a suitable date in 1998.

Regards

Rob



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