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Why does the Commodore C128 perform poorly when running CP/M?

I'm Linards Ticmanis, the guy who put out the CPMFAST package in 1999 that has been mentioned several times in the other answers (although I go by the nickname TeaRex on here). While creating that, I ...
TeaRex's user avatar
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46 votes

Why does the Commodore C128 perform poorly when running CP/M?

(2017.03.03) I have added a second answer with diagrams and more technical details. This answer is already huge and self-contained; the other focuses on the complexities due to hardware. Why does the ...
RichF's user avatar
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24 votes
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Benchmark test that was used to characterize an 8-bit CPU?

There are three primary benchmarks used during this period. They are not strictly "CPU" tests, but were often used for that purpose. The almost unknown Rugg/Feldman suite from 1977. This ...
Maury Markowitz's user avatar
21 votes
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How can you measure time using BASIC on Atari XL computers?

On the Atari 8-bit machines, you'd use the real-time clock memory locations starting at offset 18; these are updated during every vertical blank: TIME = INT((PEEK(18) * 65536 + PEEK(19) * 256 + PEEK(...
Stephen Kitt's user avatar
18 votes

Why does the Commodore C128 perform poorly when running CP/M?

My first answer attempts to answer all the OP's questions without going too deep into the hardware details. Since posting that answer, I have had the pleasure of corresponding for several days with ...
RichF's user avatar
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15 votes
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ZX BASIC REM statement overhead

I just dug out a copy of The Complete Spectrum ROM Disassembly in order to see what's actually going on. The answer is a bit more complex than you'd expect. The main interpreter loop is implemented ...
Jules's user avatar
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14 votes
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Can the CSG 65CE02 CPU be used to accelerate an Apple //e or //c?

I don't think it would work. Two main reasons come to mind: You probably need an external clock that is running at (say) 4MHz to have the chip run at speeds over the default 1.024MHz. The ZipChip / ...
bjb's user avatar
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11 votes

Where can I read the article from Personal Computer World, Nov 1978, which introduced the 8th Rugg/Feldman test program?

I have a full collection of 1978 and 1979 PCW magazines. The Benchmark Tests are documented in Vol. 1 No. 1 under the article "Direct Addressing: Where to get your Personal computer". The ...
Mike D's user avatar
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10 votes
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How good was Woz's FP code?

Steve Wozniak wrote most of his software to be compact rather than fast, reflecting the constraints of affordable memory hardware of his time. That often resulted in contortions that made it run ...
Chromatix's user avatar
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10 votes
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First appearance of the Sieve in Byte *as a benchmark*?

The earliest use, as far as I can determine, of the sieve of Eratosthenes as a benchmark in Byte’s editorial content is in the September 1981 issue, page 180: “A High-Level Language Benchmark”. The ...
Stephen Kitt's user avatar
10 votes

Commodore BASIC: why was the PET's GOTO so slow?

Further to WimC's explanation, here's perhaps the worst-case example that's possible on an 8K PET 2001. This code runs in 2.2 seconds: 10 REM AA ... 762 MORE LINES LIKE THIS ... 7640 REM AA 7650 T=...
scruss's user avatar
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8 votes
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Where can I read the article from Personal Computer World, Nov 1978, which introduced the 8th Rugg/Feldman test program?

No online resource found, but to record for posterity, here are some relevant links: The Centre for Computing History (Cambridge, UK) has a list of covers and brief summaries of contents. As you note ...
TripeHound's user avatar
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8 votes

Benchmark test that was used to characterize an 8-bit CPU?

For assessing floating-point performance, there was the Savage benchmark. It was proposed by Bill Savage of Microfloat in Houston, Texas, and published in the Ray Duncan column "16-bit Software ...
njuffa's user avatar
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8 votes

Relay computer performance

Well, a good datapoint here may be the Zuse Z3 and Z4 computers. Not at least as their workings are close related to today's computers in being tact controlled as well as using binary floating point ...
Raffzahn's user avatar
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7 votes

Commodore BASIC: why was the PET's GOTO so slow?

If memory serves, the BASIC in the C64 and VIC-20 checks whether a GOTO line number is greater than or equal to the present line number and will scan from the start of the current line if so, and ...
supercat's user avatar
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6 votes

Why does the Commodore C128 perform poorly when running CP/M?

According to this Wikipedia article, the Z80 in the C128 was stepped down to 2MHz: The C128 runs CP/M noticeably slower than most dedicated CP/M systems, as the Z80 processor runs at an ...
Jeff Zeitlin's user avatar
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6 votes
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Benchmark between Home computers? What can be a valid parameter for that?

If your focus is on Commodore products from 1977 to 1984, then MIPS would likely be the wrong way to differentiate. I believe the whole line used a 1 MHz 6502 chip, meaning MIPS will be basically the ...
RichF's user avatar
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6 votes

(Modern?) Examples of Creative Computing/Ahl benchmark being used?

While it's impossible to give a definitive negative answer, I'd say that it's unlikely that other publications depended on Ahl's benchmark, because: It tests just the looping performance and accuracy ...
scruss's user avatar
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6 votes
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Commodore BASIC: why was the PET's GOTO so slow?

PET basic v2 only starts scanning from the current line if the high byte of the goto line number is greater than the high byte of the current line number. Otherwise it starts at the beginning of the ...
WimC's user avatar
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6 votes

Benchmark test that was used to characterize an 8-bit CPU?

The circa-1981 Byte Sieve benchmark may have originally been conceived as a programming language benchmark. But the algorithm consisted of such a simple set of intrinsic basic operations (adds, ...
hotpaw2's user avatar
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6 votes
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Did the ARM-1 really outperform the 387?

The answer is no. Finding numbers for the 387 is trivial, googling "387 whetstone test" brings you right to a great page that gives you a number of 5.68 MWIPS for the 386/387 at 40 MHz. ...
Maury Markowitz's user avatar
5 votes

First appearance of the Sieve in Byte *as a benchmark*?

Not exactly what you are looking for, but meets the technical statement of "a pointer to the first appearance of this code as a benchmarking tool in that magazine" and is earlier than Stephen Kitt's ...
manassehkatz-Moving 2 Codidact's user avatar
5 votes

Can the CSG 65CE02 CPU be used to accelerate an Apple //e or //c?

In 2014 I installed a 65CE02 (removed from an Amiga A2232 serial card) into an Apple IIe, for the purpose of confirming the bug in the 65CE02 decimal subtract, said bug having been discovered by Pavel ...
Eric Smith's user avatar
5 votes

Did the ARM-1 really outperform the 387?

I suspect the difference may lie in the floating-point formats. BBC Basic for the Archimedes used a 5-byte Microsoft format that could be noticeably quick in software, even on the 8-bit BBC Micro, and ...
John Dallman's user avatar
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4 votes

Benchmark between Home computers? What can be a valid parameter for that?

See the other answers re: potential issues with benchmarking the Commodores (i.e. the results will probably all be the same), but as to potential sources Personal Computer World ('PCW') had a standard ...
Tommy's user avatar
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4 votes

How to measure time with frame resolution or better using BASIC in an Oric Atmos 48K

It turns out that the information about system variables were at the end of the disassembly document. This is an excerpt from it: $272,$273 Keyboard timer. $274,$275 Cursor timer. $276,$277 ...
mcleod_ideafix's user avatar
4 votes

Where can I read the article from Personal Computer World, Nov 1978, which introduced the 8th Rugg/Feldman test program?

Since this question was asked, there is now a slightly better Personal Computer World collection at the Internet Archive. The article that introduces the benchmarks — “Direct Addressing: Where to get ...
scruss's user avatar
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3 votes

Benchmark between Home computers? What can be a valid parameter for that?

Early personal computer magazines published several tiny benchmarks. One of the earliest portable benchmarks was Byte Sieve, published in Byte Magazine in multiple articles circa 1981 thru 1984. ...
hotpaw2's user avatar
  • 8,277
3 votes

Benchmark between Home computers? What can be a valid parameter for that?

Comparing processor architectures is tricky because they are all very different. How fast something can be done depends not only on the clock speed, instructions available, RAM speed, and how many bus ...
Tim Locke's user avatar
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3 votes

Where can I read the article from Personal Computer World, Nov 1978, which introduced the 8th Rugg/Feldman test program?

I have the original 1978 copy volume 1 no 1. As pointed out by Chromatix there is a typo in BM5 and BM6 which should be the same as BM4 and BM7. I wrote a program in Liberty Basic to illustrate these ...
Barry's user avatar
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