This page is a wiki. Please login or create an account to begin editing.

SlideRule / YaCa 2.x

No votes yet
Year released:
[www].se [ftp].se [mirror].us [mirror].de
YaCa_2.0.2.sit (101.92 KB)
MD5: 60cc93103b60e9d5e8ffb1330f544fdf
For System 7.0 - 7.6 - Mac OS 9
[www].se [ftp].se [mirror].us [mirror].de
YaCa_2.1.sit (104.35 KB)
MD5: df2c542eba5c506b8116773d976b256e
For System 7.0 - 7.6 - Mac OS 9
[www].se [ftp].se [mirror].us [mirror].de
YaCa_2.2.sit (104.55 KB)
MD5: 69b326528c1c3ed574a5fe6a4d44a2c5
For System 7.0 - 7.6 - Mac OS 9
[www].se [ftp].se [mirror].us [mirror].de
YaCa_2.3.sit (105.61 KB)
MD5: 96aea89114e162df4aaf9498c951ef3d
For System 7.0 - 7.6 - Mac OS 9
[www].se [ftp].se [mirror].us [mirror].de
SlideRule_2.4.sit (116.42 KB)
MD5: bd3b15492ecb93eb05d0675628d97c26
For System 7.0 - 7.6 - Mac OS 9
[www].se [ftp].se [mirror].us [mirror].de
SlideRule_2.4.1.sit (116.49 KB)
MD5: 97b06d98130621b1bcfc1f1cd049dced
For System 7.0 - 7.6 - Mac OS 9
[www].se [ftp].se [mirror].us [mirror].de
SlideRule_2.4.2.sit (148.08 KB)
MD5: c04f8538db7d55c96bee6a5eb853b7b4
For System 7.0 - 7.6 - Mac OS 9
[www].se [ftp].se [mirror].us [mirror].de
SlideRule261K.sit_.bin (140.88 KB)
MD5: 8a8c07208040919cc4ba378476a50191
For System 7.0 - 7.6 - Mac OS 9
[www].se [ftp].se [mirror].us [mirror].de
SlideRule261P.sit_.bin (134.50 KB)
MD5: 095493020e2962e3e09d2b0e9c1f1253
For System 7.0 - 7.6 - Mac OS 9
[www].se [ftp].se [mirror].us [mirror].de
SlideRule270.bin (135.75 KB)
MD5: 75d5779c65ef22bf4b0d23d635b4e28e
For System 7.0 - 7.6 - Mac OS 9
[www].se [ftp].se [mirror].us [mirror].de
SlideRule271.sit_.bin (136.00 KB)
MD5: 8f78a40fc9d09c2a1510a0f882e9b688
For System 7.0 - 7.6 - Mac OS 9
[www].se [ftp].se [mirror].us [mirror].de
SlideRule30.sit (154.93 KB)
MD5: 883284c633e906bebe94213353a46235
For System 7.0 - 7.6 - Mac OS 9
[www].se [ftp].se [mirror].us [mirror].de (283.09 KB)
MD5: bc0985ecf1d91e3fbadd3702b574ab0c
For System 7.0 - 7.6 - Mac OS 9
[www].se [ftp].se [mirror].us [mirror].de
This app works with: SheepShaver, Basilisk II,

From the former SlideRule website:
"A floating point calculator with a wide range of scientific functions, number formats, conversions and memories. It can log calculations in a separate window, like a printing calculator. Other features include: Correct precedence operation, Sensitive rounding, Undo/Redo, International number formats, Colour schemes."

This app was one of the best scientific calculators for the Classic Mac OS in the 90s, besides PCalc. Non-crippled shareware. SlideRule 3.1 is freeware.

1st download: YaCa 2.0.2 (1999)
2nd download: YaCa 2.1 (1999)
3rd download: YaCa 2.2 (1999)
4th download: YaCa 2.3 (2000)
5th download: SlideRule 2.4 (2000)
6th download: SlideRule 2.4.1 (2000)
7th download: SlideRule 2.4.2 (2000)
8th download: SlideRule 2.6.1K (2000)
9th download: SlideRule 2.6.1P (2000)
10th download: SlideRule 2.7.0 (2001)
11th download: SlideRule 2.7.1 (2001)
12th download: SlideRule 3.0 (2002)
13th download: SlideRule 3.1 (2003)

Architecture: 68k PPC PPC (Carbonized)

Minimum requirements:
68020 processor, 260K of free RAM
Classic Mac OS, System 7 or later
May vary on a case-by-case basis

Yaca 2.x: 68k with System 7.0 and later
SlideRule 2.4.x: 68k with System 7.0 and later (v.2.4.2 is Fat Binary)
SlideRule 2.6.1K: 68k with System 7.0 and later
SlideRule 2.6.1P: PPC with System 7.0 and later
SlideRule 2.7.x: PPC with Mac OS 8.0 and later
SlideRule 3.x: PPC with Mac OS 8.6 and later or PPC with Mac OS X (Carbonized apps)

Version 2.4.1 tested successfully on Basilisk II for Linux w/System 7.5.5.
Version 2.4.2 tested successfully on Basilisk II for MaxOSX w/System 7.5.5.
Version 2.7.1 tested successfully on SheepShaver for MacOSX w/Mac OS 9.0.4.
Version 3.1 tested successfully on Mac OS X 10.6.8 Snow Leopard w/Rosetta.

Strangely, the behavior of version 2.6.1K does not make any sense on Basilisk II although it seems fine running in SheepShaver. Just an illusion, results are sometimes foolish. Situation is worse for YaCa 2.x on both emulators.


Idéfix's picture
by Idéfix - 2019, January 20 - 4:46pm

I am still puzzled about that accuracy issue of SlideRule on emulators. Some more thoughts about it:

1) I am aware of the existence of that classic rounding bug directly related to processor limitations. Differences between SlideRule results and those of MacOSX calculator (+ PCalc3 to make sure) were however much larger than a tiny fraction of unit. So, it should be something else.

2) I don't beleive the author has released his software knowing that it was so buggy. When looking carefully at his app, documentation and website it is easy to see that he was thorough. And the version history (see "manual" upside) confirms that he has worked a lot to improve rounding subroutines.

3) I have also done a comparative test yesterday with version 3.1 running directly on MacOSX Snow Leopard. And you know what? No difference at all between SlideRule and the MacOSX calculator, except for the number of digits after the dot. This would tend to confirm the seriousness of the author for his work.

4) I don't remember having any such problems with YaCa 2.x and SlideRule 2.4.x when they were running on my old Performa 580CD w/System 7.5.1 twenty years ago. Maybe the app was really running fine, maybe I simply didn't notice the accuracy problem because most of my calculations were done otherwise.

WhosIt.There's picture
by WhosIt.There - 2019, January 20 - 5:42am

With a name like "SlideRule" a proper slide rule, not a digital calculator. Sad

There's actually weird calculation bug in most apps due to the wacky way computers store decimal numbers, including Microsoft Excel. I have a spreadsheet that sums two columns of currency numbers (normal dollars and two decimal place cents such as $5.37) as a crosscheck to make sure they are the same ... often it comes up with a difference of something like 0.000000000000000001, which is impossible, but causes the spreadsheet to tell me there is an error when there really isn't.

Idéfix's picture
by Idéfix - 2019, January 20 - 3:20am

BEWARE! I did several comparative tests between the MacOSX calculator and SlideRule 2.7.1 running on SheepShaver. The results are disturbing since there are sometimes large differences in the results of calculations using trigonometric and logarithmic functions. Difficult to say if this embarrassing situation could be explained by some particularities of the emulators or if it's simply the floating point subroutines of SlideRule that are bugged. I urge you to be careful if you plan to use this program to do serious work. I also suggest you to do your own tests, on emulators as well as on real Macs.