16 Feb
2022
16 Feb
'22
8:54 p.m.
markus schnalke <meillo(a)marmaro.de> writes:
Hoi.
[2022-02-16 00:54] arnold(a)skeeve.com
Apparently it was a popular benchmark back in the day:
https://www.tuhs.org/Archive/Documentation/AUUGN/AUUGN-V05.1.pdf
Dave Horsfall <dave(a)horsfall.org> wrote:
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?
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? 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(a)vuxu.org> https://leahneukirchen.org/