* [TUHS] History of cal(1)?
@ 2025-09-22 18:18 Douglas McIlroy via TUHS
2025-09-23 0:34 ` [TUHS] " John Levine via TUHS
0 siblings, 1 reply; 6+ messages in thread
From: Douglas McIlroy via TUHS @ 2025-09-22 18:18 UTC (permalink / raw)
To: TUHS main list
> [cal(1)] has all the logic to adjust for 16th century
> calendar changes ... (Try "cal 9 1752")
> My impression is that [it is] overimplemented.
The fact that a 16th century change is illustrated by an 18th century
example suggests that not quite "all the logic" is there. It's good
for Great Britain and its colonies, but not elsewhere. So I'd say it's
underimplemented :)
Doug
^ permalink raw reply [flat|nested] 6+ messages in thread
* [TUHS] Re: History of cal(1)?
2025-09-22 18:18 [TUHS] History of cal(1)? Douglas McIlroy via TUHS
@ 2025-09-23 0:34 ` John Levine via TUHS
2025-09-23 1:05 ` Steffen Nurpmeso via TUHS
0 siblings, 1 reply; 6+ messages in thread
From: John Levine via TUHS @ 2025-09-23 0:34 UTC (permalink / raw)
To: tuhs; +Cc: douglas.mcilroy
It appears that Douglas McIlroy via TUHS <douglas.mcilroy@dartmouth.edu> said:
>> [cal(1)] has all the logic to adjust for 16th century
>> calendar changes ... (Try "cal 9 1752")
>> My impression is that [it is] overimplemented.
>
>The fact that a 16th century change is illustrated by an 18th century
>example suggests that not quite "all the logic" is there. It's good
>for Great Britain and its colonies, but not elsewhere. So I'd say it's
>underimplemented :)
You'll be relieved to know that ncal has addressed that omission:
$ ncal -p
AL Albania 1912-11-30 IS Iceland 1700-11-16
AT Austria 1583-10-05 IT Italy 1582-10-04
AU Australia 1752-09-02 JP Japan 1918-12-18
BE Belgium 1582-12-14 LT Lithuania 1918-02-01
BG Bulgaria 1916-03-31 LU Luxembourg 1582-12-14
CA Canada 1752-09-02 LV Latvia 1918-02-01
CH Switzerland 1655-02-28 NL Netherlands 1582-12-14
CN China 1911-12-18 NO Norway 1700-02-18
CZ Czech Republic 1584-01-06 PL Poland 1582-10-04
DE Germany 1700-02-18 PT Portugal 1582-10-04
DK Denmark 1700-02-18 RO Romania 1919-03-31
ES Spain 1582-10-04 RU Russia 1918-01-31
FI Finland 1753-02-17 SI Slovenia 1919-03-04
FR France 1582-12-09 SE Sweden 1753-02-17
GB United Kingdom 1752-09-02 TR Turkey 1926-12-18
GR Greece 1924-03-09 *US United States 1752-09-02
HU Hungary 1587-10-21 YU Yugoslavia 1919-03-04
R's,
John
PS: my point was not that it's a lot of code, but that is's a distinctive hack so one might
look at earlier calendar programs to see whether they also did it to try and trace the
chain of influence.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [TUHS] Re: History of cal(1)?
2025-09-23 0:34 ` [TUHS] " John Levine via TUHS
@ 2025-09-23 1:05 ` Steffen Nurpmeso via TUHS
2025-09-23 1:50 ` Rob Pike via TUHS
0 siblings, 1 reply; 6+ messages in thread
From: Steffen Nurpmeso via TUHS @ 2025-09-23 1:05 UTC (permalink / raw)
To: John Levine via TUHS; +Cc: douglas.mcilroy
John Levine via TUHS wrote in
<20250923003454.03671DD56E9A@ary.qy>:
|It appears that Douglas McIlroy via TUHS <douglas.mcilroy@dartmouth.edu> \
|said:
|>> [cal(1)] has all the logic to adjust for 16th century
|>> calendar changes ... (Try "cal 9 1752")
|>> My impression is that [it is] overimplemented.
|>
|>The fact that a 16th century change is illustrated by an 18th century
|>example suggests that not quite "all the logic" is there. It's good
|>for Great Britain and its colonies, but not elsewhere. So I'd say it's
|>underimplemented :)
|
|You'll be relieved to know that ncal has addressed that omission:
|
|$ ncal -p
| AL Albania 1912-11-30 IS Iceland 1700-11-16
| AT Austria 1583-10-05 IT Italy 1582-10-04
| AU Australia 1752-09-02 JP Japan 1918-12-18
| BE Belgium 1582-12-14 LT Lithuania 1918-02-01
| BG Bulgaria 1916-03-31 LU Luxembourg 1582-12-14
| CA Canada 1752-09-02 LV Latvia 1918-02-01
| CH Switzerland 1655-02-28 NL Netherlands 1582-12-14
| CN China 1911-12-18 NO Norway 1700-02-18
| CZ Czech Republic 1584-01-06 PL Poland 1582-10-04
| DE Germany 1700-02-18 PT Portugal 1582-10-04
(In an earlier thread on this topic Mr. McIlroy threw into
the discussion that for example Germany was very much more
complicated than that. And i said iirc something like "we
tried to keep it local by then" [actually notoriously so], and
unfortunately talked about Mors Teutonicus even, as "we more
usually than not reached the Holy Land" before reaching the holy
land, which *possibly* is the only one and true way to reach the
holy land .. if you can. (Pffffhh, what a talk.))
| DK Denmark 1700-02-18 RO Romania 1919-03-31
| ES Spain 1582-10-04 RU Russia 1918-01-31
| FI Finland 1753-02-17 SI Slovenia 1919-03-04
| FR France 1582-12-09 SE Sweden 1753-02-17
| GB United Kingdom 1752-09-02 TR Turkey 1926-12-18
| GR Greece 1924-03-09 *US United States 1752-09-02
| HU Hungary 1587-10-21 YU Yugoslavia 1919-03-04
|
|R's,
|John
|
|PS: my point was not that it's a lot of code, but that is's a distinctive \
|hack so one might
|look at earlier calendar programs to see whether they also did it to \
|try and trace the
|chain of influence.
--End of <20250923003454.03671DD56E9A@ary.qy>
--steffen
|
|Der Kragenbaer, The moon bear,
|der holt sich munter he cheerfully and one by one
|einen nach dem anderen runter wa.ks himself off
|(By Robert Gernhardt)
^ permalink raw reply [flat|nested] 6+ messages in thread
* [TUHS] Re: History of cal(1)?
2025-09-23 1:05 ` Steffen Nurpmeso via TUHS
@ 2025-09-23 1:50 ` Rob Pike via TUHS
2025-09-23 3:57 ` Bakul Shah via TUHS
0 siblings, 1 reply; 6+ messages in thread
From: Rob Pike via TUHS @ 2025-09-23 1:50 UTC (permalink / raw)
To: Steffen Nurpmeso, John Levine via TUHS, douglas.mcilroy
There are so many calendars in the world. The Muslim calendar. The Jewish
calendar. The Mayan calendar. Countless indigenous calendars too, I am
certain.
Whenever computing butts up against real human culture, things get messy
fast. No point in trying to catalog the mess exhaustively.
-rob
On Tue, Sep 23, 2025 at 11:14 AM Steffen Nurpmeso via TUHS <tuhs@tuhs.org>
wrote:
> John Levine via TUHS wrote in
> <20250923003454.03671DD56E9A@ary.qy>:
> |It appears that Douglas McIlroy via TUHS <douglas.mcilroy@dartmouth.edu>
> \
> |said:
> |>> [cal(1)] has all the logic to adjust for 16th century
> |>> calendar changes ... (Try "cal 9 1752")
> |>> My impression is that [it is] overimplemented.
> |>
> |>The fact that a 16th century change is illustrated by an 18th century
> |>example suggests that not quite "all the logic" is there. It's good
> |>for Great Britain and its colonies, but not elsewhere. So I'd say it's
> |>underimplemented :)
> |
> |You'll be relieved to know that ncal has addressed that omission:
> |
> |$ ncal -p
> | AL Albania 1912-11-30 IS Iceland 1700-11-16
> | AT Austria 1583-10-05 IT Italy 1582-10-04
> | AU Australia 1752-09-02 JP Japan 1918-12-18
> | BE Belgium 1582-12-14 LT Lithuania 1918-02-01
> | BG Bulgaria 1916-03-31 LU Luxembourg 1582-12-14
> | CA Canada 1752-09-02 LV Latvia 1918-02-01
> | CH Switzerland 1655-02-28 NL Netherlands 1582-12-14
> | CN China 1911-12-18 NO Norway 1700-02-18
> | CZ Czech Republic 1584-01-06 PL Poland 1582-10-04
> | DE Germany 1700-02-18 PT Portugal 1582-10-04
>
> (In an earlier thread on this topic Mr. McIlroy threw into
> the discussion that for example Germany was very much more
> complicated than that. And i said iirc something like "we
> tried to keep it local by then" [actually notoriously so], and
> unfortunately talked about Mors Teutonicus even, as "we more
> usually than not reached the Holy Land" before reaching the holy
> land, which *possibly* is the only one and true way to reach the
> holy land .. if you can. (Pffffhh, what a talk.))
>
> | DK Denmark 1700-02-18 RO Romania 1919-03-31
> | ES Spain 1582-10-04 RU Russia 1918-01-31
> | FI Finland 1753-02-17 SI Slovenia 1919-03-04
> | FR France 1582-12-09 SE Sweden 1753-02-17
> | GB United Kingdom 1752-09-02 TR Turkey 1926-12-18
> | GR Greece 1924-03-09 *US United States 1752-09-02
> | HU Hungary 1587-10-21 YU Yugoslavia 1919-03-04
> |
> |R's,
> |John
> |
> |PS: my point was not that it's a lot of code, but that is's a
> distinctive \
> |hack so one might
> |look at earlier calendar programs to see whether they also did it to \
> |try and trace the
> |chain of influence.
> --End of <20250923003454.03671DD56E9A@ary.qy>
>
> --steffen
> |
> |Der Kragenbaer, The moon bear,
> |der holt sich munter he cheerfully and one by one
> |einen nach dem anderen runter wa.ks himself off
> |(By Robert Gernhardt)
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* [TUHS] Re: History of cal(1)?
2025-09-23 1:50 ` Rob Pike via TUHS
@ 2025-09-23 3:57 ` Bakul Shah via TUHS
0 siblings, 0 replies; 6+ messages in thread
From: Bakul Shah via TUHS @ 2025-09-23 3:57 UTC (permalink / raw)
To: TUHS
Things get quite complicated when you have lunisolar calendars!
An extra lunar month is added every 32 or 33 lunar months to sync
up with the solar cycle[1]. In India they have been in use for
many centuries and even today most religious festivals and events
follow them. Here's a typical calendar page[2]:
https://www.prokerala.com/general/calendar/hinducalendar.php?year=2025&mon=september&sb=1#calendar
As you can see plenty of information is imparted[3]. When I was
a kid, we would always get a day-per-page calendar every year
because of this.
[1] One's birthday as per Indian & Greorian calendars lines up almost
exactly every 19 years.
[2] Not sure what software they use. The calendar also changes based
on your location!
[3] Things like sunrise/sunset, the zodiac moon is passing through,
etc. Details explained here:
https://www.anaadi.org/post/indian-calendar-part-3-the-panchangam
> On Sep 22, 2025, at 6:50 PM, Rob Pike via TUHS <tuhs@tuhs.org> wrote:
>
> There are so many calendars in the world. The Muslim calendar. The Jewish
> calendar. The Mayan calendar. Countless indigenous calendars too, I am
> certain.
>
> Whenever computing butts up against real human culture, things get messy
> fast. No point in trying to catalog the mess exhaustively.
>
> -rob
>
>
> On Tue, Sep 23, 2025 at 11:14 AM Steffen Nurpmeso via TUHS <tuhs@tuhs.org>
> wrote:
>
>> John Levine via TUHS wrote in
>> <20250923003454.03671DD56E9A@ary.qy>:
>> |It appears that Douglas McIlroy via TUHS <douglas.mcilroy@dartmouth.edu>
>> \
>> |said:
>> |>> [cal(1)] has all the logic to adjust for 16th century
>> |>> calendar changes ... (Try "cal 9 1752")
>> |>> My impression is that [it is] overimplemented.
>> |>
>> |>The fact that a 16th century change is illustrated by an 18th century
>> |>example suggests that not quite "all the logic" is there. It's good
>> |>for Great Britain and its colonies, but not elsewhere. So I'd say it's
>> |>underimplemented :)
>> |
>> |You'll be relieved to know that ncal has addressed that omission:
>> |
>> |$ ncal -p
>> | AL Albania 1912-11-30 IS Iceland 1700-11-16
>> | AT Austria 1583-10-05 IT Italy 1582-10-04
>> | AU Australia 1752-09-02 JP Japan 1918-12-18
>> | BE Belgium 1582-12-14 LT Lithuania 1918-02-01
>> | BG Bulgaria 1916-03-31 LU Luxembourg 1582-12-14
>> | CA Canada 1752-09-02 LV Latvia 1918-02-01
>> | CH Switzerland 1655-02-28 NL Netherlands 1582-12-14
>> | CN China 1911-12-18 NO Norway 1700-02-18
>> | CZ Czech Republic 1584-01-06 PL Poland 1582-10-04
>> | DE Germany 1700-02-18 PT Portugal 1582-10-04
>>
>> (In an earlier thread on this topic Mr. McIlroy threw into
>> the discussion that for example Germany was very much more
>> complicated than that. And i said iirc something like "we
>> tried to keep it local by then" [actually notoriously so], and
>> unfortunately talked about Mors Teutonicus even, as "we more
>> usually than not reached the Holy Land" before reaching the holy
>> land, which *possibly* is the only one and true way to reach the
>> holy land .. if you can. (Pffffhh, what a talk.))
>>
>> | DK Denmark 1700-02-18 RO Romania 1919-03-31
>> | ES Spain 1582-10-04 RU Russia 1918-01-31
>> | FI Finland 1753-02-17 SI Slovenia 1919-03-04
>> | FR France 1582-12-09 SE Sweden 1753-02-17
>> | GB United Kingdom 1752-09-02 TR Turkey 1926-12-18
>> | GR Greece 1924-03-09 *US United States 1752-09-02
>> | HU Hungary 1587-10-21 YU Yugoslavia 1919-03-04
>> |
>> |R's,
>> |John
>> |
>> |PS: my point was not that it's a lot of code, but that is's a
>> distinctive \
>> |hack so one might
>> |look at earlier calendar programs to see whether they also did it to \
>> |try and trace the
>> |chain of influence.
>> --End of <20250923003454.03671DD56E9A@ary.qy>
>>
>> --steffen
>> |
>> |Der Kragenbaer, The moon bear,
>> |der holt sich munter he cheerfully and one by one
>> |einen nach dem anderen runter wa.ks himself off
>> |(By Robert Gernhardt)
>>
^ permalink raw reply [flat|nested] 6+ messages in thread
* [TUHS] History of cal(1)?
@ 2025-09-18 16:53 Dan Cross via TUHS
0 siblings, 0 replies; 6+ messages in thread
From: Dan Cross via TUHS @ 2025-09-18 16:53 UTC (permalink / raw)
To: TUHS
Over on the Multicians list, Jeffrey Johnson asked a question about
the Multics `calendar` program, which was written by Tom van Vleck in
Dec, 1973. Despite what some man pages say, the analogous Unix `cal`
program appears to have arrived in the 5th Edition (mid 1974).
Jeffrey's question was whether `cal` was inspired by `calendar`?
My suspicion is that it was not, and this is a case of parallel
invention: after all, a program that prints out a calendar is
obviously useful. I also suspect that program, or something
substantially similar, had existed for quite a while before someone
tossed it into /usr/source/s1 in time for 5th Edition. Does anyone
recall who wrote it, and when?
But this also rekindles my curiosity about something I've always
wondered: what _was_ the level of communication between the folks at
Bell Labs and the Multics people after 1969? By all accounts,
individuals remained friendly and collegial with one another, but it
seems like communication (let alone collaboration) between the two
"camps" was minimal. Is that accurate?
- Dan C.
^ permalink raw reply [flat|nested] 6+ messages in thread
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2025-09-22 18:18 [TUHS] History of cal(1)? Douglas McIlroy via TUHS
2025-09-23 0:34 ` [TUHS] " John Levine via TUHS
2025-09-23 1:05 ` Steffen Nurpmeso via TUHS
2025-09-23 1:50 ` Rob Pike via TUHS
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