4 Apr
2011
4 Apr
'11
6:16 a.m.
Is there any interest in extending any of the PDP-11 operating systems
so that they are able to support dates at least until 3000? While my
personal interest lies with RT-11, I am curious if anyone has looked
at the requirements for any of the other PDP-11 operating systems
to determine what is required for Y3K date support? In addition,
are the resources (technical knowledge, files to make the required
changes and hardware to support the development) available?
For RT-11, the resources are available and I suggest a review of
the required software changes by anyone who has the technical
background to evaluate any proposals for Y3K implementation.
If other individuals who are interested in RSX-11, RSTS/E and
TSX-Plus are motivated to support Y3K implementation for
these OSs, I would be interested in providing support for
any solutions required to exchange dates between all PDP-11
operating systems.
I am not sure if there is any commercial impact to producing
Y3K code for PDP-11 OSs. However, it is possible that
any current commercial use MIGHT be more likely if Y3K
support is available. On the other hand, it is almost certain
that any Y3K projects for all PDP-11 OSs must be done
without any commercial support at this time. Consequently,
as with all DECUS contributions, any actual code changes
would become available to everyone. If this enhances the
commercial value of the PDP-11 OSs, then it should be a
positive development.
Responses and suggestions are appreciated.
If, as I have noted in the past there is no response, then at
some point when it seems worthwhile, I shall at least present
the technical details of what is required to implement Y3K for
RT-11. There may also be details of other enhancements along
with RT-11 bug fixes. If anyone has a wish list for RT-11 or
knows of any RT-11 bugs which need fixing, I would very much
appreciate the help.
Jerome Fine
4 Apr
4 Apr
4:47 p.m.
Didn't you mean to send this last Friday?
Actually I'd be more interested in Y1K support since I am using
an 11/34 as the navigational computer in my time machine, and it
only goes back in time.
:-)
On 4/4/2011 6:16 AM, Jerome H. Fine wrote:
Is there any interest in extending any of the PDP-11
operating systems
so that they are able to support dates at least until 3000? While my
personal interest lies with RT-11, I am curious if anyone has looked
at the requirements for any of the other PDP-11 operating systems
to determine what is required for Y3K date support? In addition,
are the resources (technical knowledge, files to make the required
changes and hardware to support the development) available?
For RT-11, the resources are available and I suggest a review of
the required software changes by anyone who has the technical
background to evaluate any proposals for Y3K implementation.
If other individuals who are interested in RSX-11, RSTS/E and
TSX-Plus are motivated to support Y3K implementation for
these OSs, I would be interested in providing support for
any solutions required to exchange dates between all PDP-11
operating systems.
I am not sure if there is any commercial impact to producing
Y3K code for PDP-11 OSs. However, it is possible that
any current commercial use MIGHT be more likely if Y3K
support is available. On the other hand, it is almost certain
that any Y3K projects for all PDP-11 OSs must be done
without any commercial support at this time. Consequently,
as with all DECUS contributions, any actual code changes
would become available to everyone. If this enhances the
commercial value of the PDP-11 OSs, then it should be a
positive development.
Responses and suggestions are appreciated.
If, as I have noted in the past there is no response, then at
some point when it seems worthwhile, I shall at least present
the technical details of what is required to implement Y3K for
RT-11. There may also be details of other enhancements along
with RT-11 bug fixes. If anyone has a wish list for RT-11 or
knows of any RT-11 bugs which need fixing, I would very much
appreciate the help.
Jerome Fine
4:56 p.m.
On Mon, 4 Apr 2011, Don North wrote:
Didn't you mean to send this last Friday?
Actually I'd be more interested in Y1K support since I am using
an 11/34 as the navigational computer in my time machine, and it
only goes back in time.
Of course. It's all abandonware, because there's no future in time
travel.
5:49 p.m.
Don North wrote:
Didn't you mean to send this last Friday?
I thought about that possibility. The post was ready to go, but there
seemed to be TOO much of a probability it would be taken that way.
Actually I'd be more interested in Y1K support
since I am using
an 11/34 as the navigational computer in my time machine, and it
only goes back in time.
Already taken into account. The only question is how far back?
While my initial start year was around 9999 BCE, I settled for the
year 1588 CE (= 1972 - 3 * 128). Since the Gregorian Calendar
started in 1582, there would not be any question of needing the
proleptic Gregorian Calendar dates (dates which would be in effect
if the Gregorian Rules had been used prior to 1582). However,
if you need all of the dates for positive years staring with 1 CE, that
can easily be accommodated.
Would a start year of 52 CE (=1972 -15 * 128) be acceptable?
Otherwise, -76 CE (77 BCE) is the next starting date.
If you haven't realized, my intention is to keep all of the lower 16 bits
for the extended date identical to the currently used bit pattern for
dates from January 1st, 1972 to December 31st, 2099. That allows
all current programs which have not been made Y3K compliant to
run until December 31st, 2099 if the program is Y2K compliant.
If a program is Y3K compliant, then dates prior to 1972 will also
be possible.
On 4/4/2011
6:16 AM, Jerome H. Fine wrote:
Is there any interest in extending any of the
PDP-11 operating systems
so that they are able to support dates at least until 3000? While my
personal interest lies with RT-11, I am curious if anyone has looked
at the requirements for any of the other PDP-11 operating systems
to determine what is required for Y3K date support? In addition,
are the resources (technical knowledge, files to make the required
changes and hardware to support the development) available?
[Snip]
Responses and suggestions are appreciated.
If, as I have noted in the past there is no response, then at
some point when it seems worthwhile, I shall at least present
the technical details of what is required to implement Y3K for
RT-11. There may also be details of other enhancements along
with RT-11 bug fixes. If anyone has a wish list for RT-11 or
knows of any RT-11 bugs which need fixing, I would very much
appreciate the help.
6:19 p.m.
From: Jerome H. Fine
Sent: Monday, April 04, 2011 5:49 PM
> Don North wrote:
> Actually I'd be more interested in Y1K support
since I am using
> an 11/34 as the navigational computer in my time machine, and it
> only goes back in time.
Already taken into account. The only question is how
far back?
While my initial start year was around 9999 BCE, I settled for the
year 1588 CE (= 1972 - 3 * 128). Since the Gregorian Calendar
started in 1582, there would not be any question of needing the
proleptic Gregorian Calendar dates (dates which would be in effect
if the Gregorian Rules had been used prior to 1582). However,
if you need all of the dates for positive years staring with 1 CE, that
can easily be accommodated.
You have forgotten to take into account the fact that the Gregorian
calendar was not adopted in by English speakers until 1752, by which
time an 11th day had to be dropped from the calendar. While the Catholic
countries in Europe adopted the Gregorian calendar in 1582, dropping 10
days in October, the English and their colonies took another 170 years,
and dropped 11 days in September of that year.
So any time-warping calendar program needs to take not only the date but
the location into account.
It is far better to use Julian days (not related to the Julian calendar
which the Gregorian revised), and calculate from there to dates on any
shorter-term calendar.
Rich Alderson
Vintage Computing Sr. Server Engineer
Vulcan, Inc.
505 5th Avenue S, Suite 900
Seattle, WA 98104
mailto:RichA at vulcan.com
mailto:RichA at LivingComputerMuseum.org
http://www.LivingComputerMuseum.org/
8:11 p.m.
Rich Alderson wrote:
From: Jerome H. Fine
Sent: Monday, April 04, 2011 5:49 PM
You have forgotten to take into account the fact that the Gregorian
calendar was not adopted in by English speakers until 1752, by which
time an 11th day had to be dropped from the calendar. While the Catholic
countries in Europe adopted the Gregorian calendar in 1582, dropping 10
days in October, the English and their colonies took another 170 years,
and dropped 11 days in September of that year.
So any time-warping calendar program needs to take not only the date but
the location into account.
In addition, other countries such as Russia adopted the Gregorian Calendar
at a much later date. I am not sure when the US adopted the Gregorian
Calendar, but it was probably around the same time.
After considering how few dates will be used prior to 1900, I concluded
that the
Gregorian Calendar can be used as a common set of dates rather than
making the
different set of exceptions for all of the different countries. And
prior to 1582,
the proleptic Gregorian Calendar would provide a continuous set of dates
without
any gaps.
Plus, supporting dates prior to 1972 was really in response to Don North,
although I suspect it was more of an April Fool's suggestion.
Don North
wrote:
Actually I'd be more interested in Y1K support since I am using
an 11/34 as the navigational computer in my time machine, and it
only goes back in time.
Already taken into account. The only question is how far back?
While my initial start year was around 9999 BCE, I settled for the
year 1588 CE (= 1972 - 3 * 128). Since the Gregorian Calendar
started in 1582, there would not be any question of needing the
proleptic Gregorian Calendar dates (dates which would be in effect
if the Gregorian Rules had been used prior to 1582). However,
if you need all of the dates for positive years staring with 1 CE, that
can easily be accommodated.
It is far better to use Julian days (not related to the
Julian calendar
which the Gregorian revised), and calculate from there to dates on any
shorter-term calendar.
Switching to Julian Days would provide a better solution, but the majority
of Common Era (CE) dates are expressed via the more familiar months
of January to December with a day number and a CE year. I suspect
that the confusion of Julian Days would not be worth the extra precision.
The imposition of using a proleptic Gregorian Calendar for dates in
countries
which had not switched should not be a huge burden if dates prior to 1900 CE
are rarely needed, let alone used.
If in the future, Julian Days prove to be a popular request for the
date, then
code could be added for its support.
Jerome Fine
4793
days inactive
4794
days old
5 comments
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participants (4)
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ak6dn＠mindspring.com -
cisin＠xenosoft.com -
jhfinedp3k＠compsys.to -
RichA＠vulcan.com