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johnklos

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  1. There were 24 bit address versions of the m68020, like the m68EC020 in the Amiga 1200. Aside from the slight benefit of having it in a physically smaller package for mass production, there was no benefit to the idea of an "SX" version of either the '020 or '030 because they both supported dynamic bus sizing. You can easily use either on an 8 bit data bus, if you were so inclined, and that's exactly how Apple made machines with 16 bit data busses.
  2. I have an L88M CPU, and I tried it at higher speeds, and got nothing. I suspect the clock generator chips can't run that fast. On the other hand, if we recreated all the clocks that come from the clock generator ourselves, we could test lots of things... Hmmm...
  3. It was all too confusing to me, so when I had a PCI board, I just removed the maybe-3.3 volt / maybe-ground pin and fed the motherboard from a physically installed 3.3 volt regulator:
  4. The ImageWriter drivers are installed as part of the OS. Since you have it working on your Classic, you should be able to just copy the ImageWriter extension from the Classic's System Folder to your SE.
  5. I'm not a fan of the Vampire. First, they're trying too hard to make their own idea of an incompatible Motorola CPU successor. What value is there in making a CPU replacement which supports old software while at the same time trying to encourage programmers making new software which uses CPU additions which mean the new software won't run on real Motorola CPUs? Second, they don't care very much about compatibility. FPU support was a very low priority, and it appears that they're not interested in MMU support. This means that virtual memory is not possible, nor is runnin
  6. I've run 128 meg DIMMs in many PCI Macs including a 7300 with 1 gig and a 9600 with 1.5 gigs for many years. No problems, so long as you get the right DIMMs. Mine were from Other World Computing, so they're correct and have a lifetime warranty.
  7. Nope. All the original hardware is still available and used. The CPU is emulated and other hardware is made available by virtue of direct attachment to the CPU.
  8. On the Mac motherboard, you can have up to 196 megabytes. One slot will take 128 megs, the other (if you have it) will take 64 megs, and of course there's 4 megs soldered on. I tested my Quadra / Performa 6xx with the motherboard at 25 MHz with a NewerTech Quadra Overdrive running the CPU at 50 MHz, and with the motherboard and CPU running at 40 MHz. Because all bus access slows down the Quadra Overdrive to 25 MHz, things were mostly faster at 40 MHz.
  9. Not sure how many people have Macs with socketed m68000, but there's this: https://github.com/captain-amygdala/pistorm Since it can run on a pure m68000 machine, it should be easily adaptable to use in a Mac. I'm sure it's just a matter of time before it, or projects like it, are extended to 32 bit CPUs for m68020 / m68030 / m68040 sockets.
  10. A few people have asked how I make use of modern SCA SCSI disks with older machines. Since high end 10000 or 15000 RPM 3.5" drives are overkill speedwise, and since most of us don't really need 300 gigs on our older machines, I've settled on 70 gig 2.5" disks such as the IBM 90P1316, the IBM 90P1313 and the IBM 26K5158. They're 10000 RPM drives which can communicate at Ultra-320 speeds ,so they're still much more than we generally need, but they're comparatively new, require less power than a 3.5" disk (although they still do require 12 volts) and they're cheap at around $15 USD ea
  11. Modern DDR memory runs communication to the computer's bus at many gigahertz (whatever the memory is rated for), but in reality dynamic RAM is still not all that much faster than it ever has been. Memory access time in the late 1980s was typically in the range of 60 to 100 nanoseconds. The fastest DDR4 memory in the world can only manage access in around 8 nanoseconds. That represents a speed increase of eight to ten times faster, while density has increased ten thousand fold. This is why DDR exists - you pipeline reads and writes so that you're waiting that full 8 nanoseconds as i
  12. Replying to my own post! Astr0baby does run lots of older systems and updates toolchains and stuff, but for NeXT specific stuff, check out Fun with virtualization, which has lots of interesting NeXT stuff.
  13. Last note: Linux on Alpha wasn't a player. You're forgetting that Tru64 could run on one system or it could run on the #2 supercomputer in the world. Nothing on x86 at that time could even come close to that kind of spread. Reliability in the context of scientific computing wasn't about train switching and 911 operations, but I think you know that. I'd love to hear if the HP PA-RISC this thread is about will eventually run NeXTStep. Astr0baby runs lots of older OSes and even gets modern toolchains and software running on them. Check out the site What're your plans with
  14. That's not how anything works. It didn't work that way then, and it doesn't work that way now. In the scientific and academic worlds, people will buy the best equipment for the problems they primarily want to solve. Clustering already existed and worked in DEC's OSes. We still, in 2020, don't have the kind of clustering robustness that DEC had in the 1990s. Sure, for the money, people then could've just bought cheap PCs and gotten more performance per $ than if they had bought Alpha, but trying to get those PCs to form a robust and reliable cluster that just works without lots of extra
  15. Oops. I made a mistake - my Sun Fire v245 has 400 MHz DDR, and my AlphaServer DS25 has 125 MHz SDR.
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