Have an IBM PC compatible on the 486 or the first Pentium? Please run it for me!

[Vol]

I have written small programs which may be used as a benchmark. It is a number pi calculator that can give us any digits of the pi. It also outputs the amount of time spent on each calculation.
I am gathering timings for 100, 1000, and 3000 digits. I have found out that emulators are rather inaccurate with timings and they especially inaccurate for the 486+ systems. So I need data from real hardware. I need just 3 timings for a system, optional screenshots (one for every system) are welcome too. For the 386+ systems, would you like also to run the 80386/80486 optimized programs (pi-pc386/pi-pc486)? It is very interesting to know what program is the best fit for the 80486 or Pentium.
These programs are for the old good DOS.
Thank you.

 

[Kai Robinson]

Any particular DOS version required?

 

[Vol]

Any particular DOS version required?

It should work even with the first DOS but newer versions are ok too. I can provide a version for DOS compatible computers which don't have standard BIOS but it is rather redundant for the 486/Pentium machines.

 

[Mu0n]

@Vol , here you go
Results from my 486 IBM 425 SX/S ValuePoint (no L2 cache; but upgraded to a 486 DX2/66 cpu) with 32 mb RAM and MS-DOS 6.22


Results in text format:

pi-ibmpc:

100 digits = 0.00
1000 digits = 0.55
3000 digits = 4.61

pi-pc386:

100 digits = 0.00
1000 digits = 0.55
3000 digits = 4.89

pi-pc486:

100 digits = 0.00
1000 digits = 0.55
3000 digits = 4.89



screenshots:

pi-ibmpc:

pi-pc386:

pi-pc486:

 

[Mu0n]

The pc-ibm version may seem faster but it starts with this strange V180 and I don't recognize the sequence of decimals afterwards.

 

[Vol]

@Vol , here you go
Results from my 486 IBM 425 SX/S ValuePoint (no L2 cache; but upgraded to a 486 DX2/66 cpu) with 32 mb RAM and MS-DOS 6.22

Results in text format:

pi-ibmpc:

100 digits = 0.00
1000 digits = 0.55
3000 digits = 4.61

pi-pc386:

100 digits = 0.00
1000 digits = 0.55
3000 digits = 4.89

pi-pc486:

100 digits = 0.00
1000 digits = 0.55
3000 digits = 4.89

Thank you very much for your results. I have just published them - http://litwr2.atspace.eu/pi/pi-spigot-benchmark.html - I didn't publish a screenshot because all screenshots (but for the PI-IBMPC) have strange marks on them. These marks contain the "copy text from image" button, the share button, the zoom button, ... It seems that you used a different OS for PI-IBMPC and for other programs, right?
Your results with PI-IBMPC.COM is an actual mystery. I can't understand how this is possible. I tested this program very thoroughly under emulators and real hardware. In particular, I tested it on my 386 @25Mhz, Celeron @766Mhz, and AMD Phenom @3200MHz machines under pure DOS - it works fine. What is your processor id?

 

[Mu0n]

Thank you very much for your results. I have just published them - http://litwr2.atspace.eu/pi/pi-spigot-benchmark.html - I didn't publish a screenshot because all screenshots (but for the PI-IBMPC) have strange marks on them. These marks contain the "copy text from image" button, the share button, the zoom button, ... It seems that you used a different OS for PI-IBMPC and for other programs, right?
Your results with PI-IBMPC.COM is an actual mystery. I can't understand how this is possible. I tested this program very thoroughly under emulators and real hardware. In particular, I tested it on my 386 @25Mhz, Celeron @766Mhz, and AMD Phenom @3200MHz machines under pure DOS - it works fine. What is your processor id?

All my tests were done on the same machine.

What program do you recommend to check the processor id? Can you provide a link to it? It's just a normal Intel 486 dx2/66. All tests were performed on a compact flash card (512 mb), booted by a real 320mb hard disk (on drive C) containing mdsos 6.22.

 

[Vol]

All my tests were done on the same machine.

What program do you recommend to check the processor id? Can you provide a link to it? It's just a normal Intel 486 dx2/66. All tests were performed on a compact flash card (512 mb), booted by a real 320mb hard disk (on drive C) containing mdsos 6.22.

Standard system information can show the id but the best method is to look at the chip. It would be great if we can detect the hardware error for this chip.
I can't understand how can the marks appear under DOS? Why are they on screenshots for PI-PC386 and PI-PC486 and there are none for PI-IBMPC? Any hint?

 

[Mu0n]

Standard system information can show the id but the best method is to look at the chip. It would be great if we can detect the hardware error for this chip.
I can't understand how can the marks appear under DOS? Why are they on screenshots for PI-PC386 and PI-PC486 and there are none for PI-IBMPC? Any hint?

I don't understand your post. I've posted 6 screenshots, all ordered as I wrote in the text part.

Screenshot 1: pi-ibmpc for 100 and 1000
Screenshot 2: pi-ibmpc for 3000
Screenshot 3: pi-pc386 for 100 and 1000
Screenshot 4: pi-pc386 for 3000
Screenshot 5: pi-pc486 for 100 and 1000
Screenshot 6: pi-pc486 for 3000

 

[Vol]

I don't understand your post. I've posted 6 screenshots, all ordered as I wrote in the text part.

Screenshot 1: pi-ibmpc for 100 and 1000
Screenshot 2: pi-ibmpc for 3000
Screenshot 3: pi-pc386 for 100 and 1000
Screenshot 4: pi-pc386 for 3000
Screenshot 5: pi-pc486 for 100 and 1000
Screenshot 6: pi-pc486 for 3000

Look at the screenshots #2-4 and #6, they have the marks at the top. The screenshots #1 and #5 don't have them. However the #5 is for the 486 so there is no connection to the PI-IBMPC strange results, so I confused some things. I am writing a test which can detect what instruction on your CPU works untypical. It may take several days.

 

[Mu0n]

I'm sorry to have caused confusion with the markings of my screenshots.
Here's why they happened:
I took photos with my phone. The photos synced up in Google photos after a short delay.
I took lower res partial screen caps of them before I pasted them in this thread. This causes me to catch the small message overlay above them (only some of the times). If I had taken screencaps directly on my dos machine, this issue wouldn't have happened. However, I don't have a DOS terminate stay resident screencap utility handy (it's been 30 years ish since I used one).

Here are the pure text results which I captured by launching your programs and setting an output stream, like so:

pi-ibmpc > ibm100.txt

and typing '100' and enter blindly since it expects an entry from me.

 

[Mu0n]

Just for funsies, here are the results when I use a x86 system-on-module from ICOP, the Vortex86DX running at 800 MHz (warning, this is not matching a 800 MHz cpu; the closest equivalent in processor power is more akin to pentium 2 233 MHz) in my WeeCee

ibm:
100 = 0.00
1000 = 0.05
3000 = .33

386:
100 = 0.00
1000 = 0.05
3000 = 0.33

486:
100 = 0.00
1000 = 0.05
3000 = 0.33

it also doesn't exhibit the strange 'V180' at the start of the ibm tests.

 

[Vol]

I'm sorry to have caused confusion with the markings of my screenshots.
Here's why they happened:
I took photos with my phone. The photos synced up in Google photos after a short delay.
I took lower res partial screen caps of them before I pasted them in this thread. This causes me to catch the small message overlay above them (only some of the times). If I had taken screencaps directly on my dos machine, this issue wouldn't have happened. However, I don't have a DOS terminate stay resident screencap utility handy (it's been 30 years ish since I used one).

Here are the pure text results which I captured by launching your programs and setting an output stream, like so:

pi-ibmpc > ibm100.txt

and typing '100' and enter blindly since it expects an entry from me.

Thank you very much for your explanation. However I had no doubts about the results you received, you know, I have published them. So I just tried to find an explanation about strange results from PI-IBMPC.
I have written a program that can help us to find out what is a peculiarity of your CPU that causes the strange results. This program prints tracing information. Please run it on your PC
pi-log >trace.txt
and send TRACE.TXT to me.

 

[Vol]

Just for funsies, here are the results when I use a x86 system-on-module from ICOP, the Vortex86DX running at 800 MHz (warning, this is not matching a 800 MHz cpu; the closest equivalent in processor power is more akin to pentium 2 233 MHz) in my WeeCee

ibm:
100 = 0.00
1000 = 0.05
3000 = .33

386:
100 = 0.00
1000 = 0.05
3000 = 0.33

486:
100 = 0.00
1000 = 0.05
3000 = 0.33

it also doesn't exhibit the strange 'V180' at the start of the ibm tests.

So this confirms that your ValuePoint has some issue. Thanks for interesting information about your WeeCee. IMHO it is better to use the maximum to test modern systems. And no need to send me the digits of the pi, they are very well known. Just check the first digits 31415...
I use 9264 digits when I test modern hardware. Maybe it will be interesting for somebody to know results from my systems.

the Celeron @766Mhz
ibmpc 2.20
pc386 2.47
pc486 2.42

the AMD Phenom @3200Mh
ibmpc 0.99
pc386 0.99
pc486 0.99

I ran the tests under pure DOS.

 

[Mu0n]

Thank you very much for your explanation. However I had no doubts about the results you received, you know, I have published them. So I just tried to find an explanation about strange results from PI-IBMPC.
I have written a program that can help us to find out what is a peculiarity of your CPU that causes the strange results. This program prints tracing information. Please run it on your PC
pi-log >trace.txt
and send TRACE.TXT to me.

Here you go:

p0115
000E
p0142
0000
p0164
0000
000E
001C
2710
p023B
2D00
0007
0131
001B
2D00
0131
p01A3
0131
2D00
0000
001B
2D00
000B
0008
p0280
4D84
000B
0014
001B
0131
p01F8
4D84
000B
0014
EFB4
0092
p023B
1CB4
000B
01C4
0019
1CB4
01C4
p01A3
01C4
1CB4
0000
0019
1CB4
0012
0002
p0280
15A0
0012
0014
0019
01C4
p01F8
15A0
0012
0014
0380
00D9
p023B
3080
0012
020A
0017
3080
020A
p01A3
020A
3080
0000
0017
3080
0016
0010
p0280
B432
0016
0002
0017
020A
p01F8
B432
0016
0002
BE26
00F9
p023B
EB26
0016
022A
0015
EB26
022A
p01A3
022A
EB26
0000
0015
EB26
001A
0008
p0280
6CB8
001A
000E
0015
022A
p01F8
6CB8
001A
000E
3F30
0108
p023B
6C30
001A
0239
0013
6C30
0239
p01A3
0239
6C30
0000
0013
6C30
001D
0012
p0280
F838
001D
0008
0013
0239
p01F8
F838
001D
0008
B9F8
010D
p023B
E6F8
001D
023E
0011
E6F8
023E
p01A3
023E
E6F8
0000
0011
E6F8
0021
000D
p0280
D159
0021
000F
0011
023E
p01F8
D159
0021
000F
8AC8
010E
p023B
B7C8
0021
023F
000F
B7C8
023F
p01A3
023F
B7C8
0000
000F
B7C8
0026
0005
p0280
6195
0026
000D
000F
023F
p01F8
6195
0026
000D
AB13
010C
p023B
D813
0026
023D
000D
D813
023D
p01A3
023D
D813
0000
000D
D813
002C
0001
p0280
2450
002C
0003
000D
023D
p01F8
2450
002C
0003
D9E0
0108
p023B
06E0
002C
023A
000B
06E0
023A
p01A3
023A
06E0
0000
000B
06E0
0033
0009
p0280
D214
0033
0004
000B
023A
p01F8
D214
0033
0004
1A64
0103
p023B
4764
0033
0234
0009
4764
0234
p01A3
0234
4764
0000
0009
4764
003E
0006
p0280
B299
003E
0003
0009
0234
p01F8
B299
003E
0003
CA64
00FA
p023B
F764
003E
022B
0007
F764
022B
p01A3
022B
F764
0000
0007
F764
004F
0002
p0280
6C7C
004F
0000
0007
022B
p01F8
6C7C
004F
0000
4574
00EE
p023B
7274
004F
021F
0005
7274
021F
p01A3
021F
7274
0000
0005
7274
006C
0003
p0280
B07D
006C
0003
0005
021F
p01F8
B07D
006C
0003
60FA
00D9
p023B
8DFA
006C
020A
0003
8DFA
020A
p01A3
020A
8DFA
0000
0003
8DFA
00AE
0000
p0280
2F53
00AE
0001
0003
020A
p01F8
2F53
00AE
0001
2F53
00AE
p023B
5C53
00AE
01DF
0001
5C53
01DF
p01A3
01DF
5C53
0000
0001
5C53
01DF
0000
p0280
5C53
01DF
0000
0001
01DF
p02CB
0C45
01DF
1503
0C45
03E8
0C45
30064
008D
141

 

[Vol]

Here you go:

Thank you. It is often very difficult to locate a hardware peculiarity. Your TRACE.TXT contains correct data. So we need more steps to detect the peculiarity. Would you like to run PI-IBMPC to get 4 digits? They must be 3141.

 

[Mu0n]

Thank you. It is often very difficult to locate a hardware peculiarity. Your TRACE.TXT contains correct data. So we need more steps to detect the peculiarity. Would you like to run PI-IBMPC to get 4 digits? They must be 3141.

pi-ibmpc gives out:

V179 .00

 

[Vol]

pi-ibmpc gives out:

V179 .00

Your results show that every single instruction works correctly. So the problem probably is a combination of some instructions. Do you know about the famous POPAD/PUSHAD bug of all the 80386 chips?
Let's continue our efforts to find out the source of the strange results. Would you like to run the next two tests?

pi-log1 >trace1.txt
pi-log2 >trace2.txt

I need TRACE1.TXT and TRACE2.TXT for further analysis.

 

[Mu0n]

TRACES

 

[Vol]

TRACES

I can't still get any clue. I've prepared the next tests but it can be for long. It would be great if you can provide telnet/ftp or ssh access for me to your system. This can speed up things very much.
The next tests
pi-log3 >trace3.txt
pi-log4 >trace4.txt