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Now if you were to manufacture your own retro style computer..

tuanhuy

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Apr 22, 2017
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3
What would it be based on (which computer from the "era" would it be inspired by primarily)?

Cosmetically (what would it look like)?

Internally (what hardware would it sport)?

I really liked look of the Sega/Yeno SC-3000H. I had thought it would be fun to design something like that, but larger. In black of course. Probably using Coldfire stuff internally.
 

jamesbeat

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Apr 19, 2017
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Long Island, NY
Not sure if this is exactly what you have in mind, but I am currently in the process of making NY own idea of a retro style computer.

I have a Retropie console hooked up to my tv, but I came to realize that a controller/tv setup is less than ideal for emulating most of the machines I'm interested in.
I came to consoles pretty late, (snes) having mostly had computers before that.

I decided to make another Retropie setup, this time based around a monitor and keyboard.

I'm using a Raspberry Pi Zero but instead of shoehorning it into the smallest case possible, I'm putting it in a PC case, so I have room for all the additional stuff like psu, hub and usb sound card (I'm using a DVI monitor, so no sound without a separate card).
It will also have an Atari compatible joystick adapter that I made by hacking a usb gamepad. This will allow me to use a joystick with machines such as the Spectrum, C64 etc.

I'm breaking out all the ports to the back of the case, so it will be a neat self contained unit rather than the dead octopus that most Raspberry pi setups resemble.

I want to use a beige desktop style case, but I'm having a little trouble finding a reasonably priced one, so I'm building it into a beige tower for now.
I have a beige keyboard and an Atari ST mouse that I have transplanted usb optical innards into.

It will be capable of emulating the following machines:

Dragon 32
BBC Micro
ZX Spectrum
Amstrad CPC
Commodore 64
Atari ST
PC (DOS)

I'm about halfway through the build at the moment.
The system is all set up and working, but I have a lot of custom cables to solder up
 

jltursan

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Sep 24, 2010
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758
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Madrid, Spain
Funny this question pop-ups right now; recently a new machine development, VroBit has revealed that it's based in a Banana or raspberry device. Supposedly it's an advanced MSX machine with some twists. Nice!

I really like these developments :)
 

NobodyIsHere

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Dec 21, 2006
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2,394
Hi
My current retrocomputer project is an early-1990's 486 home brew Linux SBC. The PCBs are almost complete and should be ordering them in about week & a half or so.

What I'd like it to do is be able to run the Linux kernel and minimal distribution (DSL, Puppy, Basic, FreeDOS, etc.). That means it has to have at least a 486 CPU, 16MB DRAM, and a complete enough PC/AT architecture to run independently.

I'd design the computer so it fits an ATX case and uses an ATX power supply so it would work in a period correct case.

If you're interested in designing/building retro style computers you should join up on RBC. There are multiple projects underway including some Motorola 680x0 type which seem to be all the rage these days.

The "brass ring" retro style computer for me is to actually run a modern Linux kernel.
 

KC9UDX

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I started one a few years ago which came to a screeching halt when I couldn't really work on it anymore. It looks sort of like an Altair, but was to be 6502 based, and have I/O like you'd typically only find in a PDP.
 

nc_mike

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Sep 28, 2014
Messages
473
One that could multi-boot and run all vintage operating systems blazing fast and without compromise without having to modify the hardware between re-boots due the incompatible OS hardware requirements and limitations from OS to OS.

https://pcpartpicker.com/b/yJjcCJ

:)

Mike
 
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NobodyIsHere

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Based on what I've seen there is a ton of 8 bit home brew retro computers (Z80, 8085, 6502, 6809, etc.) but much fewer 16 bit projects like 8086 or 68K and very few 32 bit projects like 680x0 or x86. None 586 or later to my knowledge.

Other than MCUs or SoCs, there don't appear to be any ARM CPU (with discoverable bus) based home brew projects although there have been ARM CPUs (ARM610, etc.) they've largely gone extinct.

There has been a lot of work done with FPGAs but the complex ones tend to rely on FPGA developer boards rather than build it yourself variety. RaspPi and its ilk are almost all ARM SoCs and are great from a software perspective but few people have the skills to build one from components. Not impossible but very rare.

I'd like to see some really exotic CPU projects some day like PPC, NS 32032, ARM, MIPS R4000, etc. I think the 386/486 is under appreciated too although it is possible to build some pretty simple home brew computers with it if you don't bother with PC/AT architecture.

Another cool area I'd like to see is Intel MultiBus. There has been some hobbyist activity along these lines but not a lot. Very cool architecture and vastly superior to all its counterparts of the day. Really good engineering means there are many MultiBus systems still running in industry today... like 30+ years later. Pretty impressive. Blows away S-100 and ISA that's for sure. Intel is an engineering powerhouse which turned the 8080 into an empire.
 
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NobodyIsHere

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One that could multi-boot and run all vintage operating systems blazing fast and without compromise without having to modify the hardware between re-boots due the incompatible OS hardware requirements and limitations from OS to OS.

https://pcpartpicker.com/b/yJjcCJ

:)

Mike

Awesome. I've found there a lot of people who'll go out of their way to tell you something can't be done or its stupid for some reason or another. Usually its because they've never tried it or thought about it. Those are usually the same people who after you've done it come along to complain about some minor detail yet never offer to help. There are a lot of people like that and you're best to ignore them.
 

smbaker

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Joined
Oct 21, 2016
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Location
Oregon, USA
What would it be based on (which computer from the "era" would it be inspired by primarily)?

For me, building a retro computer means sticking with retro parts as much as practical. My recent forays into retrocomputing have been the RC2014 Z80 computer and Sergey's Xi 8088. The former you can buy a pretty good starter kit on the Internet. The latter you can buy the PCBs but you have to source all of the components yourself. The advantages to both of these designs are that they're very modular, featuring backplane designs. When I wanted to add a speech synthesizer to the RC2014, I just got out my copy of Eagle, drew up a schematic for a speech synthesizer, laid it out, and had Osh Park manufacture a PCB. If I wanted a different CPU, I made a different CPU card. Backplane designs are great. I ended up reimplementing just about everything that came in the RC2014 kit. I haven't started doing that with the Xi 8088 yet, but I do have some ideas...

As far as peripherals, I like to have floppy drives. I've got a 3.5", 5.25", and an 8" here. There's just something nostalgic about floppy drives. Hard drives seem more problematic, as early hard drives as scarce, so for both computers I've opted for solid-state CompactFlash storage. Some sort of on-board display is nice. I went with a VFD on my RC2014. The Xi 8088 currents sports nixie tubes on his front panel, though that's pretty silly.

As far as cases, one of them I went with an acrylic case (it's easy to design these up in inkskape and have them laser cut), the other one I went down to the hardware store and bought a bunch of OAK boards.
 

creepingnet

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Well, first off, it'd look like my GEM 386 that I used to have....so this....

af9c.jpg~320x480


As for the system, it'd be a 486 based PC with a AMD 5x86 133 CPU, and 4 different clock speeds (33MHz, 66MHz, 100MHz, and 133MHz) that can be switched on the fly by multiplexing oscillators of varying speeds. The bus itself would have 4 ISA slots, 2 with VLB Local bus extentions, and 3 PCI slots. That way it could be purchased as a barebones kit one can put their own vintage hardware in that they prefer. Maximum RAM is 256MB with a 1024K (1MB) L2 cache. CMOS battery is a CR2303 coin cell like a modern PC, the BIOS is flashable and able to be backed up, and the board can take mSATA SSD drives including our own cheap, low capacity versions.

The idea would be a DOS Gamer/retro-gamer oriented computer aimed at providing a cost effective retro-gaming solution to the market that's still compatible with your old hardware/software, but forwards compatible enough to allow one to use modern storage mediums for data storage.

As for the dwindling ISA, VLB, and PCI hardware? We would offer a limited selection of very well designed hardware aimed at making the machine compatible with modern peripherals to make life of DOS retro-gamers easier. Such as replacement keyboards and mice that have alps keyswitches - my main models would be the Microspeed PC-Trac Trackball, the Microsoft "Dove Bar" mouse, and the IBM Model "M" and Northgate Omnikey 102 Keyboards.

For screens, we offer a retro-themed 14" LCD in either anti-glare or gloss. These screens are regular VGA at 1024X768 resolution interlaced - basically designed to simulate a CRT without the size and power consumption of one.

the replacement cards would include a PCI SATA card, a PCI Graphics card with HDMI, SVIDEO, and COMPOSITE out, and a PCI Gigabit LAN card, as well as an ISA SB16 compatible Soundcard with Wavetable support. A PCI version that is 100% the same but for PCI bus with Multiplexing would also be available. This would continue the "Razor/Blades" model of sorts. You buy the chassis, and change it as needed.

As technologies and whatnot change or become hard to get, we would provide solutions to continue the DOS legacy.

Pre-Loaded/Preconfigured models would also be available with FreeDOS as the pre-loaded Operating system.

There also would be a SFF and Embedded version so we could expand into the Embedded applications and provide a smaller All-In-One PnP solution for people not as hardcore into retro DOS gaming as to want to take up an entire desk with it.
 

jamesbeat

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Apr 19, 2017
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71
Location
Long Island, NY
The problem with using retro parts (though a noble idea) is availability.
If this was a machine that was to be put into production, those parts might be hard to source in quantity, and may have unacceptable failure rates.

It's not totally inconcievable though. For example, the first iteration of the Analogue NT used real Nintendo chips sourced from Japanese Famicom systems.

I guess the supply ran out though, because later models use an FPGA.
 

NobodyIsHere

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I have thought about various "what if" retro computer designs over the years. One idea I've been kicking around lately is what if IBM had gone straight to Intel for the PC design rather than relying on the "IBM System/23 Datamaster" team? Allowed Intel to design a real fire-breathing 16 bit architecture implemented correctly per the IC datasheets rather than some inherently limited terribly crippled platform? Those short sighted decisions by IBM haunt us to this very day.

Some design rules:
0. completely eschew any "backwards compatibility" with the actual original IBM PC architecture
1. exclusively 16 bit wide memory and IO
2. No memory mapped devices
3. No ROMs permanently in memory, except for temporary boot ROM after hard reset immediately after copying its payload into RAM and switching out.
4. properly implemented PIC (256 levels of interrupt with a single PIC)
5. properly implemented DMA (all 16 bit channels working)
6. properly implemented PIT (multiple working channels)
7. full 16 bit IO space addressing
8. expansion bus designed for 32 bit data and address growth
9. dual serial UARTs as part of baseline design
10. properly implemented full bidirectional parallel printer port
11. real time clock with interrupt (separate from PIT)

What you'd have is a full-bore 8086, probably 8 MHz or so with 1MB of DRAM. The ISA slots would have to be different because you'd have a 16 bit data bus, 20 bit address bus, and the usual control bus signals. Peripheral cards would not have ROMs on them cluttering up the memory map and crippling the OS. You would not have the 640KB limit but rather a 1MB address space of pure contiguous RAM. No memory mapped video abominations like the MDA or CGA, rather IO mapped video like uPD7220 or intelligent video displays with processors. You'd have 256 levels of interrupts with a single PIC. Fully capable DMA and multiple working timer channels. Implement a smart IO processor (8089) and possibly an independent DRAM refresh controller (8085) to offload burdensome tasks off the CPU. And so on.

It might look externally like an IBM PC but internally the architecture would be completely different and vastly more powerful. Probably would have given other contemporary 16 bit machines (68K) a good run for the money and even delayed the need for PC/AT (286) architecture for a while longer while Intel worked out the mask issues on the 80286. This may sound strange but the limitations of the original IBM PC set in motion a terrible series of events which have crippled PCs for decades. It didn't have to be this way and things could have been different.

I wonder if anyone has tried to design the "alternate history" IBM PC using Intel design guidelines? I think the results would be fascinating.
 
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nc_mike

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All true technically, but then again, I was terribly disappointed that the Web used hobbled HTML and not a proper application of SGML back in '93, but then the Web wouldn't have taken off like it did for the masses. IBM's decisions made the mass PC market by producing a standard open platform so that the clones and aftermarkets could flourish, and if the price point were any higher (it was already at the limits), that would have killed off the mass commoditization as well, not to mention there may have been other business factors. You can't just be a Monday morning quarterback not having played on the field and factor in the myriad of critical business factors involved, not just technical purity.
 

KC9UDX

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If I'd change what IBM did, I'd use the 68000 instead of the 8088. I wouldn't have screwed DRI, competing OSs would lead to quicker innovation.

But if I'm going to build my own machine, it sure isn't going to be anything resembling the IBM PC/XT/AT series. The only good thing about them is that they are ubiquitous, in which case, why another?
 

NobodyIsHere

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All true technically, but then again, I was terribly disappointed that the Web used hobbled HTML and not a proper application of SGML back in '93, but then the Web wouldn't have taken off like it did for the masses. IBM's decisions made the mass PC market by producing a standard open platform so that the clones and aftermarkets could flourish, and if the price point were any higher (it was already at the limits), that would have killed off the mass commoditization as well, not to mention there may have been other business factors. You can't just be a Monday morning quarterback not having played on the field and factor in the myriad of critical business factors involved, not just technical purity.

Well, that's what's nice about being a hobbyist. We aren't constrained by the day to day critical business factors and we can afford to take a technical purist viewpoint. That's what makes it fun. Also we have the added benefit of many years of hindsight which IBM did not have at the time. I think they were trying to save their "big iron" business and saw the PC as an annoyance or a threat. It was crippled through either apathy or malevolence but either way the IBM PC architecture leaves a lot to be desired and it has left a permanent mark on personal computer development.

I think there is a myth that 68K is somehow technically superior to Intel 8086. It some ways that's valid but not in an absolute sense. I see it more that IBM's decisions on the IBM PC design were more of the problem. Intel's 8086 designs were very powerful but you'd never know that if your only exposure to Intel was the IBM PC and its hobbled 8088 design.
 

KC9UDX

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Myth? The 68000 was a 32-bit design. IBM did not use the 8086, so even if the 8086 and 68000 were comparable, it's not fair to compare them in this situation.

For that matter, the 6502 would have been a better choice than the 8088. However, it wasn't a 32-bit design when IBM was designing the 5150.

Really though, if I had been making the decision at the time, I'd probably use a more conventional non-microcomputer design. It would have been easy enough to make a small system based around PDP-11 or bit-slice processors. (I'm not saying I think IBM would allow that).
 

krebizfan

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IBM did use the 8086. See the PS/2 Model 25 and 30 which were turbo XT designs using 8 MHz 8086 for the CPU. IBM also had the DisplayWriter which used the 8086 back in 1980.

The 68000 had two major drawbacks in 1981: cost and supply. $1000+ CPUs result in very high system prices. Motorola couldn't even manage to make enough 68000 CPUs to meet the approximately 10% of the market Mac, Atari ST, Amiga, and the various workstation vendors reached.
 

KC9UDX

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They didn't use the 8086 in the PC. I'm aware of the other places they used it.

If IBM had used the 68000 in the PC, the 68000 would have had the same availability of the 8088.

Did any other large-scale manufacturer use the 8086 series? Were there any UNIX workstations?
 
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