On 20 Nov 2006 at 18:26, Roger Merchberger wrote: Not exactly under $100, but under $150, I received a flyer today from Electronix Express showng their Terasic Altera Cyclone 1C6 FPGA dev kit for $149. It looks pretty loaded: http://www.elexp.com/tst_pga1.htm Opinions? They've also got a Xilinx 95108 and Altera EPM7128 CPLD dev kits for under $80. Cheers, Chuck

On Nov 20, 2006, at 6:26 PM, Roger Merchberger wrote: ;) Go to http://www.digilentinc.com/ and look for "Spartan 3 Starter Board" under Products. It's $99. That's the one that I have, and it's wonderful. Lots of I/O (set up for VGA, PS/2 kbd/mouse, async serial), LED displays and individual LEDs, switches, RAM...and there are lots of "accessory boards" that plug into this board, like analog I/O, solderless breadboard with FPGA pin breakouts, etc etc. It really is good stuff. -Dave -- Dave McGuire Cape Coral, FL

From: "Don North" <ak6dn at mindspring.com> One of the questions I have kicking around (I even bought an XESS board) was: How hard would it be to get a PDP-8 core into an FPGA and arrange the pinout to correspond to the 6100 or 6120? Then it wouldn't be necessary to desolder 6120's from Decmates to get our SBC6120's working :-). Vince

In article <45633FEF.7000504 at mindspring.com>, Don North <ak6dn at mindspring.com> writes: You might need to homebrew a few transistors to get the right logic level. IIRC, anything can be done with discrete transistors since the logic gates are implemented that way on the chip anyway :-). With discretes you should be able to get any voltage level you need, hopefully staying within the rise and fall-time specs. Although I would think its easier to meet vintage specs nowadays with current transistor offerings. -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://blogs.xmission.com/legalize/>

Am i the only one that feels that using modern FPGA's to recreate old CPU's is getting dangerously close to just running an emulation on a modern PC ? Jos

Richard wrote: ... I'm working on that. My real job just keeps getting in the way. I've gotten it to almost boot rt-11 from a fake rl02. There's still debugging to be done but the basic concept is working. Basically it's a small cpld and a tiny arm cpu. It can be a bus master, generate interupts, dma, whatever. I'm reading the disk image from CF card but it also has a usb function port (and a serial port). I hope to finish getting rt11 up in the next month or two. It's been hanging off an extender card in an 11/44 (on it's side) for a few months now... -brad

Richard wrote: oops, sorry. I misread. I am faking the controller. It would also be cool to fake the drive. I actually plan to do that, next, as I know someone who has 2 CADR's but is ascared to spin up the old T-300 drives. I figured out it would reasonable to simulate the drive itself. It's been done before, many times, by others. I've seen at least 3-4 commercial products which pretend to be rk05's, rl's, smd disks, etc... -brad

Richard wrote: unibus. the chips are not that hard to find. -brad

On Wednesday 22 November 2006 12:40, Richard wrote: No. Just find some dead or not very valuable/useful QBUS or UNIBUS boards (like CXY08's for QBUS or most third party boards that aren't memory or disk controller), and desolder the transceivers. Or, find some modern parts which are "close enough" to Q/UNIBUS specs. It probably doesn't need to be an exact match unless you're pushing the bus length. Pat -- Purdue University ITAP/RCAC --- http://www.rcac.purdue.edu/ The Computer Refuge --- http://computer-refuge.org

Not really, the voltage levels, etc are pretty similar. But if your bus is not heavily loaded, then you can 'get away' with using open-collector TTL gates as drivers, and even 74LS14 schmitt triggers as receivers. This does not meet the spec, but it works. -tony

On 21 Nov 2006 at 19:42, Jos Dreesen / Marian Capel wrote: Well, I've done my fair time on the old equipment; in my old age, my ears ring constantly (I've never attended a rock concert nor operated heavy equipment without ear protection), I've dug crumpled and torn cards out of card readers; picked bits of ribbon out of printers and done all sorts of other unpleasant chores Old equipment for the sake of being old doesn't interest me. On the other hand, implementing a CPU in software, while being very useful when one needs something to check out the operation of legacy code, isn't quite the same to me as doing it in hardware, even if said hardware is really "programmed" also. A matter of degree, I suspect. There apparently used to be a fellow who implemented pin-compatible FPGA replacements for the Z80 and 6502 using Xilinx 4013's, but I can't find any details of his work. One of the modern chip suppliers, Innovasic, offers drop-in FPGA replacements for old MPUs and other circuits. Cheers, Chuck

In article <45637492.10102 at arachelian.com>, Ray Arachelian <ray at arachelian.com> writes: I suppose for older CPUs that were implemented in discrete logic or SSI standard parts, its fairly easy to come up with a schematic. However, for all-on-one-chip MPUs, generally there isn't a schematic available and you have to work from a behavioral specification like the datasheet. -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://blogs.xmission.com/legalize/>

Vincent Slyngstad wrote: Any chance you could use two devices? I suppose you'd have to find a way to split the gates between them and then still interconnect them but have enough pins left over for actually interfacing with the original hardware. Is there an open source VHDL compiler (or whatever the tool is) to turn the results of the VHDL into something that can be burned into the FPGA? I'm curious about the process since I've never built anything along these lines. Which would mean that you actually have an emulator of those CPU's instead of a nearly identical part. That's not necessarily bad, except that there may be subtle bugs that may creep in due to misunderstandings or undocumented opcodes, etc.

From: "Ray Arachelian" <ray at arachelian.com> It shouldn't be too hard to split the VHDL into components, if a reasonable functional partition can be decided upon. For the TC08 and similar devices, the issue really comes down to the Posibus interface and the Blinkenlights. Both are key features of the TC08, and both are very pin-hungry. The dectape interface is not that many pins :-). I'm just using the free Xilinx tools. They're not open source, but they are free-as-in-beer. Sure. Though you can revise the FPGA to fix bugs as they are discovered, and can make the timing as accurate as you like. Or even fix lameness in the original, if one were so inclined. That gets away from the original mission of restoring vintage hardware, but it would certainly make my SBC6120 more fun, and still potentially save some Decmates :-). (One of my peeves with the 6120 is that they broke time-sharing. So I actually like the idea of a 6100 with an external MMU better :-).) Vince

On Nov 21, 2006, at 1:42 PM, Jos Dreesen / Marian Capel wrote: Yes. ;) -Dave -- Dave McGuire Cape Coral, FL

On 11/21/06, Chris M <chrism3667 at yahoo.com> wrote: The danger is that the real hardware is then trashed. __________________________________________________

From: "9000 VAX" <vax9000 at gmail.com> The idea, I thought, was to re-implement some of the old CPU chips with FPGAs, then wire the FPGA into the vintage (or replica) gear to get/keep it working. I do believe that just implementing an FPGA CPU and hooking it straight to your LCD and keyboard is essentially equivalent to running a software emulator (only much slower). Vince

On Nov 21, 2006, at 6:46 PM, Vincent Slyngstad wrote: I strongly disagree with this statement in two ways. My first point of disagreement is this. Doing it in the FPGA, the FPGA's gates and internal signal routing are configured to form the arrangement of circuitry to implement a processor...in REAL HARDWARE. What if someone is unfortunate enough to still be running Windows...So they're running an emulator under Windows, and Windows blows up. Then the emulated system ceases to exist. The performance of the emulated system depends on the other stuff being run on the host system, so if you'rew orking on software, that makes benchmarking or certain types of performance optimization impossible...execution is nondeterministic. Now, if you implement a processor in an FPGA, write an operating system for that processor (possibly even a multitasking one), then write an emulator to run under that...NOW they're equivalent. My second point of disagreement is your statement that doing it in an FPGA is "much slower". Why should this necessarily be the case? You may not be able to clock the FPGA at multiple GHz, but you also don't have the overheard of another operating system and the emulator itself, which is considerable. -Dave -- Dave McGuire Cape Coral, FL

From: "Dave McGuire" <mcguire at neurotica.com> I concede your point. My comment was directed at the essentially equivalent compromises of the "user experience". I believe a modern PC operating in the Ghz can emulate a PDP-8 much faster than an FPGA clocked at, say, 50Mhz can. The software emulation overhead should only be about 20X-30X. I suppose if we include a lot of GUI stuff to emulate blinking lights and so on, it will be a much closer contest, as the FPGA can do all that in parallel. Vince

9000 VAX wrote: I don't think that this will be the case. We should have replicas and emulators, and the more the merrier. I think that emulators and replicas are an important step in preserving old hardware. Over time, it will get progressively harder to keep old machines running. At least with emulators and replicas you have some way to access the old software and get a feel of what it was about. Otherwise, you lose an important part of history, with no way to replace it. There are probably two schools of thought on this. The purist collector would rather have the machine as is, even if non-functional. The pragmatic collector would want it working. I'm leaning towards the latter. :-) There will always be folks such as ourselves who want the old hardware anyway, and will maintain it, despite the existence of emulators. As far as I know, no one is producing new PDP11's, in their original form nor IBM/360's. Having emulators for them is important, at least in that respect. Having access to replacement parts, whether they are in FPGA's or other modern components, or in the form of whole replica's is also important. Being able to keep the old machines running is the goal (at least my goal), but in the long view, they won't last forever. There are lots of things we can do to keep them running, and we should - but sometimes, that means replacing failed components. I don't view replacing components with modern equivalents any worse than replacing dried up capacitors. We should of course be honest and realize that replacing a part was done and that the machine is no longer in the original state. For example, replacing an old MFM hard drive with a CF card may keep a machine running, but it is no longer in the original state. This isn't to say that we should discard the original non-functioning components either - if you're a purist, you could always replace the failed components back, and return the machine to it's original, but non-functional state. At some point, once you've replaced most of the original parts, it's no longer the original machine, but rather an equivalent in the same case. But unlike old vases, statues, chairs, tapestry, or what not, with machines, the goal isn't to keep them in the exact state you've found them in, but rather to keep them running. A powered off computer that's on display in a museum is in a state that you cannot interact with it, and is no longer useful in the sense that you can't experience interacting with it. Knowing that a given CRT was amber or green isn't the same as seeing it, or feeling the heat and static electricity (and even smells) it gives off , or what happens when there's a magnet nearby, versus seeing output on a modern LCD display. Seeing an old model-m keyboard isn't the same as typing on it, getting tactile and auditory feedback from it, versus a doing the same with a modern cheapo keyboard. It's ok to see something powered off behind a glass window, in a protected environment but the experience is lacking in a lot of ways. Of course, I don't expect that a museum would let us go into some gallery and let us cut our steak with ancient knives, etc., but at least with emulators and replicas, we can do the equivalent of just that - even if it's only a partial experience. More importantly, it will keep the memories of these machines alive - even if we can't share our knowledge and experiences with future generations, at least they may stumble upon some future ftp site that has emulators along with the original software and, manuals and might spend some time learning from them. Replicas are even more important for those who weren't born in the early days and have never built a computer from parts, not just in using the replica computer, but also in building one and understanding how and why it worked. I don't know whether there are some exceedingly wealthy folks on this mailing list, but I certainly can't afford to build my own fab and thus replicate 6502's or am2901's for example. I'm sure if we looked hard enough, we could find modern replacements for some of those chips, but at some point, when that isn't possible, what would you do? An FPGA on a board wired to fit a 6502 socket would sound very good if you were in that situation. One issue with emulators is that they may differ from the original hardware in subtle ways that make them incompatible with the original hardware (aka bugs). If you have accurate schematics, at least you can build FPGA's that are near identical to the original hardware, and even slow the timing down to match it. At the same time, regarding emulators, I can load up my notebook with hundreds if not thousands of emulators and fire them up at will anytime and anywhere. It won't be the same as having access to a large building full of working machines, but close enough to keep me smiling. :-)

In article <m1Gn3jO-000IywC at p850ug1>, ard at p850ug1.demon.co.uk (Tony Duell) writes: I'm more interested in keeping wear-and-tear on the drives low and providing an ICE for it. That's why I want something that fakes the drive and not the controller. -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://blogs.xmission.com/legalize/>

On Nov 21, 2006, at 5:43 PM, Chris M wrote: Nothing of course...it depends on whether your focus is the hardware or the software. I've known people who have dumpstered classic machines when they discover emulators, because they think the software is the end-all, be-all of computing technology history. For them, emulators fill 100% of the need...the ability to see the software in action. Personally, I'm interested in both the hardware and the software, with a slight emphasis on the hardware...but my strongest interest is the *architecture*, so implementing it in an FPGA is something that I'm interested in. Despite the opinions of some, I believe there's no commonality at all between implementing a particular architecture in an FPGA and running an emulator on another computer. One can stretch and redefine and whatever if one really wants to see it that way, but I believe it's just that...a stretch. -Dave -- Dave McGuire Cape Coral, FL

What if the very last thingamabob thingee there went kaput? Huh! I mean there are no more left on planet earth. Would you then do the above there with the whatever you got thing there?? Hmm? ____________________________________________________________________________________ Sponsored Link Mortgage rates near 39yr lows. $510k for $1,698/mo. Calculate new payment! www.LowerMyBills.com/lre

On Nov 21, 2006, at 6:17 PM, Chris M wrote: Build it. Many people do have that ability, you know. -Dave -- Dave McGuire Cape Coral, FL

Tony Duell wrote: True. But vintage chips are not being made any more, so a viable replacement strategy might at least allow the rest of the vintage computer to continue computing for a little longer (or while waiting for that special old chip to show up). I'd see it as no different to making do with a modern fan if the original had gone south, or replacing the bearings with a modern equivalent. Or even powering a C=64 from something that lasts longer than a day before giving up the ghost :-) The specific case mentioned was the 6120 where it seems a common supply mechanism is to remove them from a DECmate board. If an FPGA saves a DM3 I'd see that as a good thing. It would be an equally good thing if a handful of chips and a wirewrap tool achieved the same objective. Not that I have a DM3 or an FPGA (but I do have several handfuls of chips and at least two wire-wrap tools - one of them mains-driven!). Antonio

And thusly were the wise words spake by arcarlini at iee.org I use a slightly modified C128 supply to power my C64. It has a side benefit of supplying enough current for when I use the SuperCPU. Cheers, Bryan

Richard wrote: Well, if it turned out to be easier to make a whole new KDJ-11A from scratch rather than just the chip, then that's what I'd do. Or maybe if I *could* replace just the chip but needed to modify the board to do so, I'd be inclined to look at replacing the whole board with a "modern equivalent", on the off-chance that I could eventually repair the original board. Plus, if you made a KDJ-11A entirely from scratch, you could do other stuff to it - perhaps add an instrumentation port for tracking down other problems (you'd need this for development anyway), or something to drive proper blinkenlights... Gordon.