Im looking on doing a no frills/not period correct S-100 system build. I could use all the advice you folks have in this. Im not looking to do anything fancy. Simple and hobbyist is what I am going for. I have a small 7 slot backplane and thats where I am at. So I need to source a chassis and PSU before I select some cards to build up. Since its only a 7 slot backplane. Are there any smaller Chassis systems out there?
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Looking for advice on a ground up S-100 build.... Starting with a Chassis.
- Thread starter VERAULT
- Start date
granzeier
Experienced Member
Jameco sells a couple of power supplies which will provide the proper power for your system:
Thank you! Meanwell huh? I like that idea. Should be adequate for a 1977 Imsai terminated backplane? I take it I'd need both of these for all the correct voltages.
johnx993
Experienced Member
A couple of questions...
1) looking for a vintage chassis or modern substitute? Will affect price. A vintage chassis with front panel is obviously more expensive than a blank metal box produced today.
2) the big question is what do you want to do with the system? That will affect many decisions now and in the future.
Run a monitor from EPROMS? Cassette interface? Disk interface? etc.
It may help to plan out the system you want, then lay it out in phases of construction.
-J
1) looking for a vintage chassis or modern substitute? Will affect price. A vintage chassis with front panel is obviously more expensive than a blank metal box produced today.
2) the big question is what do you want to do with the system? That will affect many decisions now and in the future.
Run a monitor from EPROMS? Cassette interface? Disk interface? etc.
It may help to plan out the system you want, then lay it out in phases of construction.
-J
pbirkel@gmail.com
Veteran Member
Technically you need *three* of them since there is a +5Vdc plus both +16Vdc and -16Vdc rails. Note that the output of the Meanwell supplies can be tweaked upwards to get close to those values, however they'll probably be fine as-is as the slight under-voltage shouldn't cut into the legacy on-board linear regulator margin significantly while still reducing their heat generation a bit. Still, something to keep in mind as you proceed. 7.5v 10A should be sufficient for a 7 slot system, but if you end up larger than that you'll likely be under-powered. So pay attention to anticipated individual board power requirements as you design. The +-16Vdc rails are mainly used to support RS-232 interfaces and analog (ADC, DAC) cards, so depending on the boards that you install they may not be used.
If you haven't looked at http://s100computers.com/index.html, you should.
For example: http://s100computers.com/My System Pages/The Box/The Box.htm
Hugo Holden
Veteran Member
You said you wanted period correct,if that is the case you should be building an analog supply with a large transformer and large filter capacitors and analog voltage regulators.
While the mean well supplies are good (I use them for a lot of new projects) they were not specifically designed for computer systems and they don't incorporate the protections that are normally built into SMPS supplies designed to power computers.
These are good questions. Lets start with 1.) I am fine with a modern simple enclosure. Again I only have a 7 slot backplane so I dont know if such a thing as a smaller enclosure exists. I have really no interest in a front switch assembly.
2.) Well I was hoping I could get ideas from you folks. I like the idea of building up all the boards myself. I was looking over the list here: http://www.s100computers.com/Cards For Sale.htm
Im seeing z80, 8088, 286, 386, 486, Various 68K, etc cpu boards. I dont know what I want yet. A simple z80 cpu running CP/m is fine, but should I do more? I dont know. Picking a non z80 cpu with only 7 slots. Is that enough?
WHAT I DO WANT is serial terminal access all the time with no extra effort. Id also like composite video if possible although VGA is a nice option.
regardless of what I pick I suppose Id need the CPU board, a serial comms board, a ram board. I see there are multi function cards with video sound and many other options. If it fits right that is a possibility.
Are these X86 cpu s-100 boards more of a testing platform or fully vetted systems that can be built up?
No I said not period correct. If that wording is confusing I am sorry. Im not going for original here. Im going for simple. I dont need to find vintage hardware if I dont need to on this build. I guess I am going for a modern build.
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maxtherabbit
Veteran Member
If you are interested in going with an analog power supply you can use my design here:
https://forum.vcfed.org/index.php?threads/building-a-clone-mits-8800.1245697/post-1435816
I have some extra bare PCBs if you're interested. I'm sure it could be readily adapted to any enclosure with the 2 sets of 4 mounting holes in the corners. I was able to build up a complete supply with transformer for about the same cost as buying the recommended 3 meanwell SMPS.
https://forum.vcfed.org/index.php?threads/building-a-clone-mits-8800.1245697/post-1435816
I have some extra bare PCBs if you're interested. I'm sure it could be readily adapted to any enclosure with the 2 sets of 4 mounting holes in the corners. I was able to build up a complete supply with transformer for about the same cost as buying the recommended 3 meanwell SMPS.
I realize you already purchased a backplane (you did not mention whether you had populated it yet) but perhaps the easiest "modern" way to build up an S100 system with enclosure/power supply/backplane is this one:
GitHub - s100projects/S100_ATX_MB: S-100 ATX Motherboard for PC Cases
S-100 ATX Motherboard for PC Cases. Contribute to s100projects/S100_ATX_MB development by creating an account on GitHub.
github.com
So far all I have is a backplane. I am in the idea stage in planning i suppose.I realize you already purchased a backplane (you did not mention whether you had populated it yet) but perhaps the easiest "modern" way to build up an S100 system with enclosure/power supply/backplane is this one:
The backplane with card cage and cards is designed to fit inside a standard ATX mid tower (or larger) enclosure. Power is supplied to the backplane using a standard ATX power supply. Contact information for the person who sells this product is provided on the web site - he is very responsive, and is a regular contributor to the S100Computers Google Groups forum.
GitHub - s100projects/S100_ATX_MB: S-100 ATX Motherboard for PC Cases
S-100 ATX Motherboard for PC Cases. Contribute to s100projects/S100_ATX_MB development by creating an account on GitHub.
I have built most of the boards on the s100computers web site, integrated into working systems.
The s100computers web site provides some recommendations for "starter system" board sets. Your 7-slot backplane will be sufficient for any of those systems. The default "terminal" for most of those systems, for the sake of software compatibility across all those boards and systems, is provided by the "Propeller Console" S100 board. You only need to connect a VGA monitor and a PS/2 keyboard to the "Propeller Console" board. Many of the systems will also work with a serial terminal, if that is what you really want to use.
A really good place to start, which also meets your requirement for use with a serial terminal for the console, is one of the following "modern design" S100 single board computers:
Z80 based: http://www.s100computers.com/My System Pages/SBC Z80 Board/SBC Z80 CPU Board.htm
8080 based: http://www.s100computers.com/My System Pages/8080 CPU Board/8080 CPU Board.htm
None of the boards on the S100Computers web site are designed to provide a composite video output. If you want an S100 video board with composite video output, you will need to look for original vintage boards, and you are also on your own integrating that vintage board into the existing system software.
Yes the x86 and 68K S100 CPU boards are fully vetted systems. The x86 systems will run CP/M-86 and MSDOS 4.1, and the latter when used with the S100 VGA board will run a lot of older MSDOS applications that require a PC compatible video display. The 68K systems will run CP/M-68K and Cromemco's Cromix-Plus operating system.
If you have any other questions about boards on the S100Computers web site, please ask.
Hugo Holden
Veteran Member
Sorry my mistake entirely, I skipped over the "not" I must have been bedazzled by the words period correct.
I probably could have worded it better ...
pbirkel@gmail.com
Veteran Member
There are expandable SBCs there. Start with one and add the backplane and so on later. This one would be an "easy on" but expandable approach:
http://s100computers.com/My System Pages/Z180 SBC/Z180 SBC.htm
"It starts off initially as a Z80 (actually an Z180) CPU board which contains a flash RAM, a USB port interface and an SD Card that can immediately boot up CPM. While it is on an S100 Bus board, initially that board has only 8 significant chips and works as a self contained computer outside the bus with a simple 9V power supply. Later on it can be built up further with more chips, placed in an S100 bus and one by one programed to interface with the 100's of S100 bus cards that are out there. It can in fact behave as a S100 bus master or slave as defined by the IEEE-696 specs."
Alternatively: http://s100computers.com/My System Pages/SBC Z80 Board/SBC Z80 CPU Board.htm
All the new S100 boards have been tested and are in use in many hobbyist systems. There's an active mail list if you want to make specific inquires (s100computers@googlegroups.com).
Thanks, Yes I did see the beginner and starter recommendations. I will look those over. I guess one of my uncertainties is mixing and matching boards. If you know them pretty well I may pick your ear on details before selecting the right boards.
If I choose a 68K based CPU board. Is cromix the only supported OS? Are there other common unix systems on S-100 68K systems? That may be of interest. And is there a dual z80/68K cpu board to build similar to what Cromemco had?
Composite video is not a deal breaker. Serial Terminal accessibility and vga is more than adequate.
I am intrigued by an x86 build (386 I think), but I dont know if it would be all that useful. I really need to think this through. I dont want to buy anything just as a novelty.
Ill look into the sbc approach. Is it common for folks to have multiple cpu boards in one system? Thats an intriguing approach. HAving the z180 cpu board act a a bus master for the whole system.
For peripheral expansion. I think I would like a FDC controller. Not sure how many folks are doing it but I think I would like a 3.5" 1.4mb floppy drive on the machine (regardless of the cpu type). Possibly a 5.25" or 8" down the road.
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Plasmo
Experienced Member
S100’s 5”x10” board size is huge amount of board space if you can use modern memory, IO, and mass storage. I think it is possible to put multiple retro 8-bit processors like Z80, Z180, 6502, 65816, 6809, 8085, etc in one S100 board sharing common memory, IO, and mass storage.
The S100Computers web site provides an impressive range of modern-design S100 boards. There is however a considerable amount of untapped potential for what can be done with those boards, in terms of software development.
Re the 68K boards. CP/M-68K is available. Cromemco CROMIX was ported to the 68030 board thanks to the considerable amount of work done by one individual and documented here: https://github.com/dwildie/cromix-s100computers . UNIX has not been implemented for the S100Computers.com 68030 board set. There are no "new design" or reproductions of the Cromemco dual Z80/68K CPU board.
Re "is it common for folks to have multiple CPU boards in one system". The answer is no. I have followed the discussions on the S100Computers Google Group for a long time, and based on discussions there it is my impression that at most a few dozen hobbyists have completed a build of more than one (let alone several) slave CPU boards for their S100 systems. By far most of the interest remains concentrated on systems running "only" a Z80-based CPU.
Re FDC controller. As you noticed, there is an FDC board in the S100Computers.com board set. Again, my impression is that only a few dozen of these boards have been built. System software support for this controller is limited - you can use it to either (a) read/write CP/M disks written by other systems using the basic 8" SSSD format or (b) read/write MSDOS format 5.25" and 3.5" disks on systems running one of the x86 CPU boards.
As you will have noticed, all these modern S100 systems have been designed to use a CF or SD card for mass storage. If it is necessary to transfer files between a "modern" S100 systems and a PC, most either (a) use a serial file transfer software utility or (b) copy the files directly to/from the CF card disk image on a PC.
Incidentally.... there is a discussion currently running in the S100 Computers Google Group on the topic of the S100 ATX motherboard I mentioned above. Someone has posted photos showing their recent build using the S100 ATX motherboard I mentioned previously, installed in a modern (and very inexpensive) Corsair-brand ATX PC enclosure.
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Ok so what I gathering is Z80 is the safe bet for the most options. X86 is good too. 68k is pretty much only good for running Cromix.
Since I already have a cromemco system with a 68k/z80... I dont have any real reason to duplicate that setup. I think z80 card based system or z180 sbc is seeming the best choice so far.
Besides the z180. Has there been any other cpu cards supported by the S100 comunity like Z380?
To be specific - there are no S100 boards that use the Z280 or Z380, and I doubt there ever will be due to limited interest within the community, lack of software, and the time and $$ required to design and bring to production a new S100 CPU board design. On the other hand, there does seem to be increasing interest in making available reproductions of vintage S100 board designs.
There is an S100 CPU board set currently available based on the PDP J-11 CPU, and my understanding is that an improved version of that board is under consideration. Likely any future development of S100 boards that support alternative CPUs will make use of an FPGA implementation of those CPUs and not the actual CPU chip itself - see https://s100projects.com/new-projects/
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