Retro Computing

MTU Micro Technology Unlimited pages updated

The MTU pages have been updated.- New are 8 documents on the MT-130 page, like DISKEX (file exchange with e.g. ...

EMUF M50734

Thanks to F.J.Kamerewerd, DL6OE, I have a photo of a EMUF 65XX with a very special CPU, the Mitsubishi M50734.This ...

TKChess Computerschaak Theo Kortekaas for the KIM-1

Theo Kortekaas, a member of the Dutch KIM User Club, published in the club magazine the KIM Kenner, Issue 11 ...

Usurpator II Chess for the 6502

Usurpator Chess for the 6800 and 6502, a book by H.G. MullerA small but capable chess playing program. Source published ...

Q-Chess 1.0

Q-Chess 1.0 is a chess program for the KIM-1, from around 1980. The programs requires memory expansion of 8K at ...

KGN COMAL KIM-1 version

COMAL is an interpreted structured language. A version for the KIM-1, Junior and DIS65 is available, distributed by the KIM ...

MOS Technology documents added

A recently acquired KIM-1, of the first generation (that means, No Revision, the first series!) came with a stash of ...

6530 hardware emulator in FPGA in 40 pin DIP

Imagine a true 6530-002 and 6530-003 replacement , the RRIOTs of the KIM-1 Now with modern FPGAs you van do ...

PAL-2 is now on sale

The longawaited successor of the PAL-1, the PAL-2 is on sale now.https://www.tindie.com/products/kim1/pal-2-a-mos-6502-powered-computer-kit/My first look at the PAL-2 is here.Here the ...

KIM-5 Resident Assembler/Editor available!

MOS Technology, part of Commodore in 1977, not only sold the KIM-1 SBC but added hardware and software as KIM ...

Different versions of KB9 Microsoft Basic for KIM-1?

RNB VAK-1 photos

Thanks to Eric Dennison I can show photos of the RNB Enterprises VAK-1 motherboard.The large motherboard and the huge case ...

The Sorbus computer

A new development! A minimal 65(C)02 system, called Sorbus designed by Sven Oliver Moll (SvOlli). Part 1 of my experience ...

Instant Assembler for the KIM-1

A program by Alan Cashin.The following text and other files are by (the 'I') Alan Cashin. I am currently ...

Corsham projects, a tribute to Bob Applegate

Bob Applegate designed and sold for many years boards of interest for KIM, AIM 65, SYM-1 and the SS50/SS-30 users, ...

RetroSpy Technologies produces a range of retro (Vintage) hardware products that are of interest for the KIM-1/SYM-1/AIM 65 owner. Also ...

How to Build a Computer-controlled Robot

Another book scanned and available on the Books page:How to Build a Computer-controlled Robot (with a KIM-1) by Tod Loofbourrow, ...

2531 to 2732 EPROM adapter

By Roy Edmund AntawI hope others may find this useful when trying to replace 2532 ROMs.It sure ain't pretty, but ...

Promax MI-650 images, EPROM dumps, information, sources

A Spanish firm developed a 6502 trainer, an SBC inspired by the KIM-1. Hexadecimal keyboard, 6 LED displays, I/O to ...

I build a RC6502 SBC

I build a RC6502 SBC and a backplane. A kit is available at Hein Pragt's webshop. Nice build, work ...

This page is about my interest in retro 8-bit small computer systems computing and electronics. And the role of Dutch electronic magazines like Elektuur and Radio Bulletin in the eighties of the 20th century. Also the Dutch users club, called KIM Gebruikersclub, which I joined in 1978 and contributed to as member of the board and as chief editor of the magazine issue 11 to 25.
The retro computing pages are documenting my experiences with 8-bit systems like the KIM-1 and its relatives such as the Apple 1 and the Junior. And various small Z80 and other systems.
I set up this archive as my personal archive of what I research on the subject. If it is of any use for others, fine, enjoy!

Magazines

In the early days of computing, magazines about popular electronics played a big role in making microprocessors available for the beginner, whether the professional or hobby electric engineer. The magazines featured here are the dutch magazines Elektuur and Radio Bulletin. From 1977 until 1996 I worked as technical editor for Radio Bulletin and published about microcomputers and more general electronics. Elektuur published also articles on these subjects, many are available here.

What is a SBC for me?

A SBC, short for Single Board Computer can be defined as a computer system, based on a microprocessor, on one printed circuit, with keyboard and display, programmable I/O ports, expansion connectors and without a casing. The ‘operating system’ is stored in a (EP)ROM, an often small amount of RAM is available to store programs and data These were the first microprocessor based computers with affordable prices for hobbyists in the late seventies of the previous century. For professionals a way of getting acquainted with the new hardware and learning the basics of programming at a (very!) low level.

Though it is a complete computer, it has a CPU, memory and I/O, it is also a very limited one. The I/O is often not more than a small keyboard with hexadecimal functions. The display is often not more than 6 or 8 seven segment LED displays, just enough to show, in hexadecimal format, addresses and data. The operating system allows entering and examining of data in memory locations, and start and stop a program. Loading and saving data is limited to either papertape readers and punches, quite common in these days, or via some modulation as data files on audio cassette recorders. Also common is the ability to attach a teletype like the ASR33.

A good example of such a SBC is the KIM-1, shown below. 2K ROM, 1K RAM, many I/O lines free, six LED displays and a keyboard with hexadecimal keys and some function keys.
Why these SBCs like the KIM-1 became so popular? One reason was the low price ($ 280 for a KIM-1, I paid 795 guilders ), so it was in the price range of the average student and hobbyist. Another is the design being open, the complete hardware description and detailed listing of the ROM was included. And it is not the frightening computer, but more a programmable piece of hardware. Because it was so easy accessible and low speed, adding and changing hardware is not hard also. Programming was not easy, but editors/assemblers that could run with some added hardware like RAM and a video terminal made that possible. The nowadays common practice of cross compiling was not available for the hobbyist then.

Besides playing with the SBC, to learn what the microprocessor is capable of, many SBCs were put to work as a sort of PLC, controlling devices in the real world.
What changed the popularity of SBCs was the wish to transfer it to a computer with a better user interface, like graphics on a video screen, a full blown keyboard, a real operating system with mass storage such as floppy drives, and a higher fun factor, a.k.a. games. Or to make it a serious computer fit for business. So SBCs became extinct fast in the mainstream hobby world when the hobbycomputer appeared on the market, like the TRS-80, PET and later the C-64, MSX etc. Even later the boring business PC killed the hobby computer, but that is another story.
It seems the SBC’s are back though: Arduino and Raspberry Pi Contact form to contribute to this fascinating hobby!