Hi, Ernest: You'll get a lot of answers to this one, but a lot depends on the definition of "better" that you use. I've recently been fiddling with techniques for taking what was, back in 1982, considered a pretty good implementation of the general case of Z80 application, e.g. the Ferguson Big Board, which used the standard Z80, and NOT the Z80-A which ran at 4 MHz instead of the standard Z80's 2.5 MHz. I've got a number of these boards so I can test the various mod's separately, and ultimately intend to use the on-board 20 MHz clock to drive a faster Z80 with the existing peripherals, since they are used relatively seldom, with the exception of the video circuitry, but that doesn't use any of the sadly inadequate Z80 peripheral devices. The Z80 SBC market was driven mainly by two factors, namely memory speed, and device cost. The Z80 was pretty cheap in itself, but its peripherals, which people in general had decided were pretty good, (I wasn't one of them, by the way.) Because of the hype put into the support chips, they were used in place of potentially better chips because they did make the design dirt simple and the supported some features that other devices didn't support, e.g. Z80 mode-2 interrupts. With today's technology you can build a board with all the capabilities of the Ferguson BigBoard, i.e four parallel ports four serial ports, local video and using a parallel keyboard rather than a terminal, using a single device, i.e. an FPGA or CPLD (take your pick)and one memory IC. When you're done, you 'll have a CPU that operates at about 25 MHz, a double/single density FDC, the parallel and serial capabilities and other features of the Ferguson board. I don't know whether the result will be better. At the one-of prices (typically 1000x the advertised price) for Xilinx FPGA's capable of this, the device won't be cheaper and unless you go to pretty high volume, that won't change significantly with other FPGA makers. CPLD's are typically much less costly, costing maybe $350 @Q1 for a device capable of doing the whole job aside from memory. If you roll your own, you can probably improve somewhat on the 25 MHz, going maybe as far as 50, but probably not with a Z80 architecture, and certainly not if you stick with the rather complex logic provided but not needed in the Z80 SIO. Since I was a logic designer back in the early days of the Z80, I have to say we can design better circuits today even when we use the technology available back then. My assertion, of course, is that we can, indeed, make a better computer, regardles of what your definition of "better" happens to be, provided that we know in advance what that target is. This is true because using the newer technology has taught us a lot and because we've had 20+ years' additional experience. If we capitalize on the later packaging technology we can make the devices smaller, and using newer power-supply technology, we can cut down on power consumption by using fewer external supplies and using the newer manufacturing technology, we can reduce overall power consumption. In 1979, we had all the LSI/MSI/SSI devices that were used in the best applications of the early-mid '80's. We also had the small surface mount technology, though not the memory density of the '82-83 timeframe. The "fast" Z80 in 1979 was the 'A' version, while, by 1981, there was the 6 MHz 'B' version. Unfortunately there was no complete support peripheral set until somewhat later. In '82 they came out with an 8 MHz "H" version. This was never supported with peripherals until the CMOS versions came along. Those 1979 models work as well today as they ever did. With I/O limitations imposed on PC's, I'm looking to use my old S-100 boxes once more for the measurement and control systems I build from time to time. Condensed versions of these old timers may come back. . . . Probably not, but who knows. Now, what was it you wanted to "improve? Dick ----- Original Message ----- From: Ernest <ernestls(a)home.com> To: <classiccmp(a)classiccmp.org> Sent: Saturday, June 24, 2000 10:56 PM Subject: Building a better "old" computer computers, what it

Hello Ernest On 24-Jun-00, you wrote: computers, what it IMHO, it should be possible, if they wanted to build one. But the proliferation of wintel boxes proves that the market moved elsewhere. I think VW found that out when they phased out the original Beetle. The new Mexican built Beetles are better than the ones from the 50's and 60's but do you really want one that bad? Or another example is vacuum tubes. The only place they still thrive today is in esoteric audio amplifiers. Look at the prices of them though . . . Regards -- Gary Hildebrand ghldbrd(a)ccp.com

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