From: Leah Neukirchen <leah@vuxu.org>
To: markus schnalke <meillo@marmaro.de>
Cc: tuhs@minnie.tuhs.org
Subject: Re: [TUHS] Lorinda Cherry
Date: Wed, 16 Feb 2022 15:54:16 +0100 [thread overview]
Message-ID: <8735kig8vb.fsf@vuxu.org> (raw)
In-Reply-To: <1nKFRN-4IZ-00@marmaro.de> (markus schnalke's message of "Wed, 16 Feb 2022 09:13:33 +0100")
markus schnalke <meillo@marmaro.de> writes:
> Hoi.
>
> [2022-02-16 00:54] arnold@skeeve.com
>> Dave Horsfall <dave@horsfall.org> wrote:
>> >
>> > You know you're a greybeard if you can remember why the DC sequence
>> > "99k2vp8opq" was so popular...
>> >
>> > -- Dave
>>
>> I guess I'm not enough of a greybeard:
>>
>> $ dc
>> 99k2vp8opq
>> 1.4142135623730950488016887242096980785696718753769480731766797379907\
>> 32478462107038850387534327641572
>> 1.3240474631771674622042627661154672512575174353366027242235650231664\
>> 2753102603147144252257620301035270505416503
>>
>> I recognize the first value as the square root of two. What is
>> the second value?
>
> Decoding the program with the manpage:
>
> 99k set scaling factor to 99 (i.e. 99 digits on output)
> 2v square root of 2
> p print it (but leave it on the stack)
> 8o switch to octal output
> p print the same value (now in octal)
> q quit
>
> More interesting is the question why you need sqrt(2) in octal?
Apparently it was a popular benchmark back in the day:
https://www.tuhs.org/Archive/Documentation/AUUGN/AUUGN-V05.1.pdf
> Tim Long: Quick Benchmarks of the Machines on Display
> A simple cpu-bound benchmark was run on each of the machines on display.
> The benchmark was "echo 99k2vp8opq I /bin/time dc > /dev/null’. It uses dc
> (the desk calculator) to calculate the square root of 2 to 99 decimal places,
> and to "print" the result in decimal and then in octal. The results are in
> fact never printed, being piped to /dev/null. The user time is all that is
> compared.
> This benchmark has been applied to a large number of machines° It has
> (up until now) been useful because most manufacturers have not optimised dc,
> so the results are not likely to have been distorted by attempts to optimise
> for benchmarks.
> The results were:
> DoEo UNITY (DE-68K) 11.3 sec
> Plexus P/25 14.1 sec
> NCR Tower 21.3 sec
> Wicat 150WS 27.3 sec
> Unison 32.6 sec
> By comparison, a VAX 11/780 clocks about 5 to 6 secs, VAX750 9 sec, PDPIIs
> range from 27 secs (11/23) to 6 secs (11/70), PDP ii/34s range from 12 to 19
> secs depending upon the presence of a cache. Perkin-Elmer range from 12o5
> secs (32/10) to 7°9 secs (32/40)o
I looks like V7 dc used 100-limbs internally, so printing in decimal
was fast, but printing in octal required conversion.
--
Leah Neukirchen <leah@vuxu.org> https://leahneukirchen.org/
next prev parent reply other threads:[~2022-02-16 14:56 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-15 22:31 Douglas McIlroy
2022-02-15 23:32 ` Steve Nickolas
2022-02-15 23:43 ` Jim Capp
2022-02-15 23:51 ` Larry McVoy
2022-02-16 0:54 ` Will Senn
2022-02-16 2:58 ` Steve Nickolas
2022-02-16 0:09 ` George Michaelson
2022-02-16 0:24 ` Dave Horsfall
2022-02-16 7:54 ` arnold
2022-02-16 8:13 ` markus schnalke
2022-02-16 14:54 ` Leah Neukirchen [this message]
2022-02-16 22:27 ` Dave Horsfall
2022-02-16 22:40 ` Andrew Diller
2022-02-17 10:14 ` Peter Jeremy via TUHS
2022-02-17 15:50 ` Adam Thornton
2022-02-17 20:23 ` Dave Horsfall
2022-02-17 10:24 ` Andy Kosela
2022-02-17 16:05 ` Andrew Hume
2022-02-17 16:38 ` Warner Losh
2022-02-16 22:42 ` Larry McVoy
2022-02-16 22:56 ` Clem Cole
2022-02-16 23:49 ` Paul Winalski
2022-02-16 23:49 ` [TUHS] Benchmarks Bakul Shah
2022-02-17 1:02 ` Larry McVoy
2022-02-17 12:36 ` [TUHS] Lorinda Cherry Stuart Remphrey
2022-02-17 19:59 ` Tom Ivar Helbekkmo via TUHS
2022-02-17 21:18 ` Dave Horsfall
2022-02-17 21:44 ` Bakul Shah
2022-02-18 8:33 ` Otto Moerbeek
2022-02-22 10:39 ` Ralph Corderoy
2022-02-22 15:53 ` Otto Moerbeek
2022-02-20 17:29 ` Derek Fawcus
2022-02-17 22:00 ` David Arnold
2022-02-18 9:58 ` Tom Ivar Helbekkmo via TUHS
2022-02-16 14:34 ` [TUHS] dc after bc Ralph Corderoy
2022-02-16 19:08 ` [TUHS] Lorinda Cherry Diomidis Spinellis
2022-02-16 20:55 ` John P. Linderman
2022-02-16 21:17 ` Andrew Hume
2022-02-16 21:59 ` Marshall Conover
2022-02-17 5:51 ` arnold
2022-02-17 22:09 ` Will Senn
2022-02-16 0:35 ` Andrew Hume
2022-02-16 8:02 ` Thomas Paulsen
2022-02-16 14:05 ` [TUHS] Shower of Dogs Ralph Corderoy
2022-02-16 14:09 ` Andrew Hume
2022-02-16 15:01 ` Larry McVoy
2022-02-16 16:57 ` Douglas McIlroy
2022-02-16 17:03 ` Dennis Boone
2022-02-16 17:18 ` Warner Losh
2022-02-16 14:09 ` Chet Ramey
2022-02-16 14:35 ` Ron Natalie
2022-02-16 14:41 ` Ralph Corderoy
2022-02-16 15:08 ` Rich Morin
2022-02-16 21:21 ` Dave Horsfall
2022-02-16 21:25 ` John Cowan
2022-02-17 3:31 ` Chet Ramey
-- strict thread matches above, loose matches on Subject: below --
2022-02-22 0:02 [TUHS] Lorinda Cherry Brian Walden
2022-03-01 21:51 ` Terry Jones
2022-02-18 3:18 Norman Wilson
2022-02-18 9:10 ` Peter Jeremy via TUHS
2022-02-15 21:17 John P. Linderman
2022-02-15 21:26 ` Dave Horsfall
2022-02-15 21:33 ` Jeffrey Joshua Rollin
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