Build my own computing system

Of course it is doable, but it depends on what you mean by a computing system.
There is a long progression of development from

vacuum tubes
transistors
integrated circuits
microprocessors
microcontrollers
single-board computers
single-chip computers

You can jump in at any stage. Take your pick.

Then there is the question of system software. Are you referring to running MS-DOS, Windows, Mac-OS, Linux or any one of hundreds of operating systems available or are you thinking of a system that plays Pong, Donkey-Kong or Space Invaders?

 

Ok, let's start with the last line.

"Basic" can mean two things. I can mean "fundamental" or it can mean the "BASIC" programming language.

If you want to write a BASIC compiler, you would not do this on the computer you are trying to create (which we call the target system). You would create the software on a PC, Mac, Linux or similar machine to run on the target system

In other words, you need a working computer to create the software for a new machine - to avoid the chicken and egg problem.

The same goes for writing a "basic" operating system.

So before designing your target machine you have to decide what software you want to run on the system and how you are going to go about creating the system.

 

Hello,

A lot of information on computers can be found in the links on the pages of the EDUCYPEDIA:
Information technology

Bertus

 

I understand that you don't know what you are getting into otherwise you wouldn't be asking questions, right? That's ok. That's what this forum is all about - helping people find there way through the jungle. We are the trail blazers. We've been there, seen it, done it.

Must computer systems, including the Apple I are based on the Von Neumann architecture. For the time being you need not concern yourself with this.

You can build a system with a microprocessor, memory, monitor, keyboard etc, but it would not do anything when you turn the power on.

There is a lot more to getting the screen show "Hello world" or whatever message you want to show on power up.

At some point you have to select a microcomputer manufacturer. There are dozens to choose from. The next step would be to select an actual chip or a chip set or chip family. Next you would go out and purchase a dev kit. This will allow you to being programming, learn about the features of a microcontroller, interfacing with monitors, keyboards etc. and start getting a feel for what it takes to write your own system software.

 

I have a book at home that was for an undergraduate EE course from about 30 years ago. The entire course (lab-oriented course) was structured around building your own functioning 8088-based computer, including laying out the board and etching it yourself. The only thing that was supplied that you didn't have to do from scratch was a BIOS image for a very minimal BIOS (because it wasn't a software/firmware course), but it walked through how the BIOS worked almost line-by-line.

I hazard to guess that courses like that have largely gone the way of the Dodo bird.

Writing your own compiler is a pretty big undertaking, but if you are willing to keep it really brain dead and restricted, is probably doable without a whole lot of the background that is usually involved.

 

Not true.

All the information you are looking for is out there. It is just that it is not current. Very few people have reasons to build their own system from scratch. I am doing that right now but I am using a single-chip solution using the ARM STM32F407.

It is a realistic project. As I said, once you choose your manufacturer and chip we can guide you from there.

If you want to build an Intel-based system, you can choose 8086, 8088, 8085, 8035 or Z80 (besides many others).

If you wish to go with Motorola/Freescale, there is 6800, 6802, 6809, 68000, 68008, 6805, 68HC11, 68HC12 etc. to choose from.

 

Well then I would choose the 8088 chip as this is based on an 8-bit bus.
It will make the hardware interface simpler.
Look for an Osborne book on an 8086/8088 system.

 

I will have to see if I can find it. I got it at TechAmerica and have always wanted to go through it and do the same thing (I might have implied that it was from a course I took, it wasn't), but have never gotten around to it. But just skimming it, it seems pretty good. Now, the devil's in the details, so it could turn out to be missing key things or to not get them across well. But if I can find it I'll post the title/author.

 

I remember seeing 8088 processors on sale by Jameco in their catalog for $0.15 each. That's probably been a decade or so ago.

 

As I said, there is a lot more to learn than just wiring some chips together, but it is still doable, depending on how much you are willing to persevere. Someone (in fact, lots of people) did it in the past. Not too many do it now or even know how to do it.

When you put together such a system it will do absolutely nothing. You will have to create a BIOS code and program it into a ROM chip. In the past this was done using a UV-EPROM. Folks don't use UV-EPROMs anymore. The next closest thing is a FLASH memory chip. So now you have to learn how to program a FLASH memory chip.

So what does this BIOS do? It may just say "hello" on the screen and ask you to select a few options.

(Did I mention that you could be getting in way over your head?)