Operating systems of the 1970s handling dates beyond the year 2000
bqt at update.uu.se
Mon Jan 19 07:03:42 CST 2015
On 2015-01-19 04:30, John Kaur wrote:
> Believe is you use 1972, that is the folding point for the calendar to get
> weeks and months correct.
> Older versions of RSTS did not do it past about mid 2000.
RSTS/E have some weird internal format that is really not very good, and
which soon will have problems again. It already did have problems, but
it was extended by explicitly saying that the date was unsigned. (The
date format is pretty much ((year-1972)*1000)+day within year. Which
obviously waste a lot of the values, as there are only 365 or 366 days
in a year. And of course, they hit problems 32 years after the start
year, which was 2004.)
I don't know what is special about 1972. I always assumed they used that
base because that's the year RSTS-11 first showed up.
> On Sun, Jan 18, 2015 at 6:07 PM, Johnny Billquist <bqt at update.uu.se> wrote:
>> On 2015-01-19 02:04, Mark Longridge wrote:
>>> After trying to get Unix v5 to understand dates beyond the year 2000 I
>>> had to wonder if any of the older operating systems from the 1970s or
>>> older could do this.
>>> So, did any operating system programmers from this time period have
>>> the foresight to use 4 digits for the year? I just checked APL/360 and
>>> it seems that it does not.
>> TOPS-20? VMS?
>> Actually RSX internally also handles it fine, but there were bugs in
>> various code that displayed dates, that assumed that the year would never
>> go beyond 99. :-)
>> 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
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
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