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johnklos

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  1. On a 512K Mac? Awesome! I thought it might fit, but I wasn't sure. I've read that the display hardware reduces memory access throughput by as much as 35% (apple.fandom.com) and that the video hardware of the 128K / 512K / Plus is different than the video hardware of the SE (Big Mess O' Wires), so I'd be interested to compare your 512K's time with that of an SE. We'll also have to run these on other Macs so we can compare the speeds from running in NetBSD to speeds running in Mac OS. For such simple code, I'd expect very small differences. For now I'm on the other side o
  2. I have results from flops.c, but that almost entirely measures the FPU with practically no help from the CPU. Perhaps that can be another thread. Related to floating point, I'm also collecting performance of ffmpeg on modern versus older CPUs such as the m68040. For instance, my LC II's m68881 is almost exactly 1/4 of the speed of my LC III+'s m68882. The first is half the clock speed and is half the memory bandwidth (16 bits versus 32 bits), so it makes sense. flops.c wouldn't be useful at comparing the m68000, though. That said, I finally had some time to try out MPW,
  3. That would be a different program. Like the difference between sieving and counting, digits of Pi can be calculated by keeping everything in memory or by calculating the digits one at a time. I think that would warrant a different thread... I replied to this with my primes benchmark because it’s small enough to fit in a single tweet. Any Pi program would be a bit bigger.
  4. Now I'm more and more curious about the results on an m68000...
  5. Wow! There's a huge performance jump between the V20 and the m68030: V20 m68030 m68030 m68040 7.16 MHz 15.667 MHz 31.334 MHz 50 MHz 8 bit bus 16 bit bus 32 bit bus 32 bit bus 15845 205 83 25.5 Relative performance per MHz 113450 3211 2600 1275 For faster machines, I usually do 1,000,000 primes: m68040 m68060 Core i3-2125 Athlon 5350 Ryzen 2700X Raspberry Pi 4 50 MHz 50 MHz 3.3 GHz 2.05 GHz 3.7 GHz 1.5 GHz 1296 939 14.89 10.4 5.5 11.8 Relative performance per MHz 64800 46950 49137 21320 20350 17700 By comparison for 1,000,000
  6. I'd say try it. There's so much physical gunk that I might imagine that the battery goo interacted with enough other stuff that it's possible (not likely, but possible) that it didn't interact all that much with the motherboard itself. I got an LC II motherboard here a few years ago which was very icky. I thought it was a goner. I scrubbed it with baking soda and a toothbrush, then washed it in a dishwasher, then recapped it, and it actually worked! Clean it up and see!
  7. No. There's no technical reason why it wouldn't work. The m68060 is missing some instructions that the '040 has, so a ROM has to set up exception traps for those instructions. The stack frames are different, too, so the ROM would have to handle this, too. Use of the MMU would require the most work, but since Mac OS defaults to not using virtual memory, this shouldn't be hard. ShapeShifter is an emulator (technically, more of a virtualizer) which runs Mac OS as a task on an Amiga. I used it for years to run Mac OS on my m68060 Amiga. All the code needed to adapt Mac OS t
  8. It goes at the speed of electricity in metal An SCA adapter is just a physical adapter. There's no electronics at all, with the possible exception of SCA adapters with termination. 8 bit width can run at up to 160 MB/sec, and wide at up to 320 MB/sec, if the controller, the drive and the cabling all support it. Only if the termination is SE (single ended) will the speed will be limited. An Adaptec 2940 should get 20 MB/sec (ultra SCSI) with a narrow cable or 40 MB/sec (wide ultra SCSI) with a fast drive.
  9. Thank you. We say here often about where 128 meg and 64 meg SIMMs work The two SIMM slot Performa 636 type motherboards will do one 128 meg and one 64 meg. The Quadra 605, of course, will take a 128 meg SIMM. The Quadra 610 will take two 128 meg SIMMs and give 132 megs total (both banks must be on each SIMM, or it won't give 64 megs per SIMM). Or, with an upgraded ROM, you can get 260 megs in a Quadra 610 or 520 megs in a Centris / Quadra 650 / 800 using bbraun's djMEMC Support For Large SIMMs.
  10. Click on the link above that says, "Tweet sized benchmark". The code is right there! I'm going to try to set up MPW and/or Think C to see if I can compile it for Mac OS. Now who'll test on an m68000 Mac?
  11. With the 16 meg SIMM installed, what do you see when you open the Memory Control Panel? Also, how much memory is available when you boot without extensions (when you hold shift on boot)?
  12. So back to the original query: there are 78,498 primes less than 1,000,000. Counting that many primes with my little benchmark takes about 25.4 seconds on a 50 MHz m68040. How much faster is this than a 7.8 MHz m68000? My rough guess, based on the fact that the clock speed is 6.4 times faster and the number of t-states per instruction is probably different by a factor of eight, is that the '040 would be about fifty times faster or so. My guess, then, is that this benchmark running on an original Mac 512K would take about 23 minutes or so. Let's give it a go! Can you compile up this
  13. Calculating primes can be done by simply counting through them or it can be done via sieving. If the former, the code will be mostly or completely run out of the CPU's cache. Doing pure counting, finding the 1,000,000th prime (different from what you posted, but it's a small benchmark I use regularly), a 50 MHz m68040 takes about 1220 seconds. A single core of an Intel Core i3 (i3-2125) at 3.3 GHz takes 14.8 seconds, and an AMD Ryzen 2600 at 3.4 GHz does the same in about 5.94 seconds. The Ryzen's clock speed is 68 times faster, which means that at the same clock speed,
  14. The boards that have one SIMM slot will support up to 128 megs in that slot. The boards that have two SIMM slots will support 128 megs in one slot and 64 megs (single banked) in the other. My Quadra 630 with a replacement two SIMM slot motherboard has 196 megs of memory (128 + 64 + 4 built-in).
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