Retro Computing

Vorstellung: The 6502 50th Anniversary Computer Badge (1975-2025)

The 6502 50th Anniversary Computer Badge (1975-2025), variant of Lee Hart's 6502 badge, to celebrate the 6502 birthday.On the ...

January 2026, the 50th birthday of the KIM-1

n 1975 MOS Technology started delivery of 65XX ICs. So 2025 marks the 50 year anniversary of the 6502!The earliest ...

How to use the time in the 6530/6532

When I acquired a KIM-1 Rev A, obviously sold by NCE/Compumart, it came with some documentation that may interest any ...

PLEASE package The Computerist

PLEASE is a very small package for a standard KIM-1. It has a tiny monitor, command interpreter and many handy ...

A small book with five experiments with the KIM-1

A small book with five experiments with the KIM-1.1. User2. Input/output3. I/O controller4. Timing5. Hardware interruptsKIM-1 experiments)

MOS Technology KIM-1 Preliminary datasheet 1976

With one of my KIM-1s (a Rev G) came a MOS Technology KIM-1 Preliminary datasheet 1976.Added to the KIM-1 manuals ...

Facebook, not now

I am administrator of several Facebook groups. But not at the moment. So if you came here looking why I ...

All documents in the MTU pages are now clean and higher quality, about 50 new PDFs.

I got hold a about 10 cm of MTU documents. Several I already had in PDF format, some not available ...

Compumart KIM-1 documents

When I acquired a KIM-1 Rev A it came with some documentation revealing its provenance:Warranty cardBrochure showing the Rev AA ...

KIM-1 Revisions update

I have added images of my recently acquired KIM-1s to the KIM-1 Revisions Images page.First version. I have a more ...

MCS6500 Instruction Set Summary cards

A collection of MCS6500 Instruction set Summary cards, reference cards that are in my collection, that came with various SBC's. ...

Digital Group added information

The Digital Group made computers with Z80, 8080, 6800 and 6502 as choice.I found a article in MICROTREK magazine 1977 ...

KIM-100

https://www.youtube.com/watch?v=XmMFTPLVG4Ihttps://www.youtube.com/watch?v=eKDvlbJAqQM

Seawell Little Motherboard

I have added some photos from a Seawell Little Mother Board and Seawall SRAM card on the Seawell page. KIM-1 ...

TECMUMAS museum

In Bad König, Westenwald, Germany, Matthias Schmitt and his wife have developed a museum dedicated to Technik called TECMUMAS. Mostly ...

Synertek pages update: SYM-1, SYM-2, KTM

New information added to the Synertek pages:Images of Synertek objects in my collectionSYM-1s, KTM/2-80, expansions, books, manuals, ICsSYM-1 ManualsVIM-1 Reference ...

SYM-1 and SYM-2 updates

Paul Schroeter gave me the dump of the SYM-2 ROM and photos of the backside.He also scanned his photocopy of ...

Another KIM-5 located!

I have found a second KIM-5, also in Germany of the KIM-5.Photos of a KIM-5 board with the Resident Assembler/Editor ...

Siemens Personal Computer PC 100 Bedienungsanleitung, Ausgabe 1981/1982

A contribution by Michael Steil of the scan of 'Siemens Personal Computer PC 100 Bedienungsanleitung, Ausgabe 1981/1982'The Siemens PC 100 ...

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. ...

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!

Dungeons And Dragons Dice Simulator For The KIM-1

In Compute! Issue 13, June 1981, a small program is published. It runs on an unexpanded KIM-1, showing a random number a...

MICRO

MICRO The 6502 Journal Published by Robert M. Tripp, The Computerist Published from 1977 tot 1983. The first y...

Compute! and Compute II

Compute! A magazine devoted mostly to 6502 computers. Apart from the Compute II period, before and afterwar...

Compumart KIM-1 Rev A

When I acquired a KIM-1 Rev A it came with some documentation revealing its provenance: Warranty card Brochure ...

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