Micro Technology Unlimited MTU pages enhanced

Dave Plummer (Dave’s Garage) received lots of documents on the MTU products with his KIM-1 in a cage system and scanned them for us.

Dave Williams (devilishdesign, vintagetech) has a MT-130, a standalone 6502 system sold by MTU with MTU cards and also scanned documents and imaged floppies.

On the internet I also found a stash of MTU products documents for the PET computer, like PET versions of the K-1008, a KIM-1 bus adapter and more.

All this made me add pages to my website, devoted to MTU. Special attention to the genius behind MTU, Hal Chamberlin. Several of his articles about music and microprocessors and a clean scan of his book Musical Applications of Microprocessors .

One of the documents is the “K-1008-2L Patches to Microsoft BASIC”. Software source of the integration of the text and graphic routines into Microsoft Basic. I already did a simple integration of the K-1008 as terminal into Basic with the Graphics Software package SDTXT and VMSUP, so I have already a lot of the code. So this source wil be typed in also!


MTU history: Hal Chamberlin

Micro Technology was around 1980 a manufacturer of products aimed at the KIM-1 and AIM 65 and SYM-1 user. Later on they made the MTU-130 computer around the 6502 and a compact version the MT-140. After the founder and technical genius Hal Chamberlin left in 1986, it became focussed on software like Karaoke.

From the current MTU website:

In 1960 in the 7th grade, David B. Cox and Howard (Hal) A. Chamberlin, Jr. became lab partners and close friends. In 1966 as a college freshman, Hal designed his own digital computer (the HAL 4096) using scrap IBM magnetic core memory planes and logic cards. David worked with Hal to design, etch and build Printed Circuit boards, select and purchase components, wirewrap the backplane and generally support Hal’s monumental effort. The HAL4096 was demonstrated publicly at the 1968 NC State University Engineer´s Fair.

At the 1967 NC State Engineer´s Fair, Hal demonstrated a punch card deck program of Do loops tuned to play the song Daisy, Daisy, give me your answer do …. This ran on the campus IBM 1630 computer. The Radio Frequency Interference (RFI) was so intense out of the computer that Hal used it as the output signal to his transistor radio! This was one of the first public showings of a computer music synthesis program.

In 1968, Hal wrote a second synthesis program that computed audio sample voltages, giving control over the harmonic content and duration of notes and chords, based on the Nyquist Theorem of digital sampling. This ran on the Biomathematics Dept. Ambilog computer with two D/A converters used to drive an HP analog X-Y plotter to generate the analog audio output recorded to a Revox tape deck. Music synthesis pioneers had to be resourceful to get their analog outputs from early digital computers!

In February 1971, after graduating from NC State with BS degrees in Electrical Engineering, David incorporated Technology Unlimited Inc. (TUI) with Hal as Vice President. Hal continued at NCSU in Electrical Engineering and received his Masters. In 1973, for a Singer-Kearfott contract, we designed and built an 18-bit A/D converter with an Intel 8008 microprocessor controlling it. This A/D design delivered a true 18-bits (all valid and without noise) for more than five years.

On March 1, 1976, David sold TUI to Hendrix electronics, the leader in Text Publishing systems for newspapers. TUI had developed the world’s leading microprocessor-floppy disc based, display word processor system. David had independently negotiated with Olivetti and A.B. Dick Co. for 2.5 years, but neither could make up their minds to take TUI’s product to market. Eventually, A.B. Dick bought the product line in 1980 and sold over $1 billion dollars worth between 1980-84.

On March 1, 1977, while still employed by Hendrix, David and Hal started Micro Technology Unlimited. Our goal then and still today is to Bring microcomputer digital audio down to everyone. Our designs are visionary and improve the creativity, productivity and quality of audio communications. It has been a real trip through the 1968-2004 period in digital audio!

In 1979, Hal’s book Musical Applications of Microprocessors was first published. It quickly became the definitive work for digital audio. Developers worldwide visited MTU to talk with us on design concepts. In 1986 Ray Kurzweil (Kurzweil Music Systems), after three years of personal offers, hired Hal away from MTU.

Some of Hal Chamberlin’s publications:

Musical applications of microprocessors, Hal Chamberlin.
1980, First Edition.
Clean scan made by Hans Otten, 2023
Byte Magazine 1977 09
A Sampling of Techniques for Computer Performance of Music
Hal Chamberlin
Byte Magazine 1980 04
Advanced Real-Time Synthesis Techniques
Hal Chamberlin
Software Keyboard interface for the KIM-1.
Hal Chamberlin
1981 01 Simulation of Musical Instruments
Hal Chamberlin
The Computer Hobbyist Magazine, 1974 -1976
Hal Chamberlin as Contributing Editor


CODOS (Channel Oriented Disk Operating System) is the name of the Disk Operating System made by MTU for KIM-1, SYM-1 and AIM-65.
It required the K-1013 floppy disk controller, 8 inch disk drive(s) and optional the K-1008 Visible Memory.

CODOS V2 was the version for the MT-130/140. Numerous software was available, see the MT-130 page for manuals.
Dave Plummer (of Dave’s Garage) has a KIM-1 system with various MTU cards, including the K-1013. W

CODOS Disk images

CODOS Manuals

CODOS Manual
CODOS User Manual
CODOS User Manual OCR’ed
QumeTrak 842 Maintenance Manual

Dave Williams has the following, not yet dumped by him, disks:

  • MACASM 1.0
  • MAGIC/L Language
  • MTU-C
  • MTU-FORTH79 2.1
  • WOPDPIC 1.0 NEC 8023 Printer Version
  • MTU-130 User Group Diskette #3
  • MTU-140 User Group Diskette #5

Dave Hassler on PAL-1

A collection of programs, examples, notes, and errata on the PAL-1 6502 hobby computer by Dave Hassler
And as a KIM-1 clone just as applicable to the KIM-1, MicroKIM, Corsham Clone board and all the replica’s that appeared the last years.

Utilities and Languages

Assemblers, disassemblers, monitors, other tools; Apple BASIC, Tiny PILOT, VTL-2.
Downloads and more information at the website of Dave Hassler and his github site. I have tested some on the KIM-1 Simulator. Binaries, documents and some with sources.

  • C’MON Lite – A simple assembler, disassembler, and monitor by Aleksi Eeben.
  • MICROMON – A fuller-featured disassembler/debugger, with search, copy, fill, compare, branch offset calculator, number converters, and hex add/subtract. B Originally by Bill Seiler.
  • MELODY MAKER – Written to make it a lot easier to enter tunes into the classic “Music Box” by Jim Butterfield, the ZIP file here contains my Melody Maker music entry program, plus full documentation — including examples of program integration for KB9, Tiny BASIC, VTL-02, etc.
  • CODE TEST – From The First Book of KIM, this is Stan Ockers’s Morse code practice program from 1976. It has been modified to run on an unexpanded PAL-1
  • LIL’ BUG – This is a suite of tools I wrote, ported, or collected to be of help to unexpanded PAL-1 users. Included are the eWozLite monitor, Wozniak and Baum’s 6502 Disassembler from 1976, Lew Edwards’ MOVIT, a search module based on Jeff Tranter’s JMON routine, plus fill, memory dump, and register print routines. The complete v0.4 program package, which loads at $0B00, is here, plus documentation and some source code.
  • LOAD & SAVE for TinyBASIC — This is a small routine modeled on the load and save in KB9.
  • eWozLite – PAL-1/KIM-1 version of the original eWOZ).
  • HUEY — From 1977, a scientific calculator with RPN and somewhat programmable.
  • J.A.S.L. – a 6502 S-RECORD LOADER
  • PTP CHECKSUM CALCULATOR – A little machine language utility that calculates the ending checksum of a single record/line of a MOS Papertape file.


  • APPLE BASIC PACKAGE – The original Apple BASIC by Steve Wozniak as used on the Apple 1, the eWOZLite monitor.
  • Tiny PILOT – 1979’s MICRO magazine Nicholas Vrtis’s Tiny PILOT, with additions by Bob Applegate and Dave Hassler.
  • FOCAL-65 – The 1977 Aresco 6502 version (v3D) of the DEC high-level language FOCAL-8 for the PDP-8.
  • PAL PILOT — A modified port of Michael Tinglof’s VIC and PET PILOT Interpreter, which appeared in COMPUTE! Magazine in Dec. 1982. .
  • VTL-02 – A Very Tiny Language
  • LANGUAGE PACK for Unexpanded 5K PAL-1 – Tiny BASIC, VTL-02C, and Tiny PILOT all bundled up in a ZIP file

Docs, Eexamples, and Help

Small programs and texts that illustrate a programming technique helpful for KIM-1, PAL-1 and MicroKIM users

  • Porting CBM Basic programs to KIM-1 Basic (KB9)
  • Comparison of 7 high-level languages for 6502 machines
  • Setting up a two-dimensional array in Tiny Basic
  • For VTL-2: better ‘returns’ , peek-n-poke, ml thoughts
  • Apple Basic (A1B): using strings as data holders


A collection of games in KB9, Tiny Basic, VTL-2, PILOT, and 6502 assembly language, some even original.

The 6502 show

Dave made a number of videos worth watching:
FOCAL-65: A deeper dive into a not-quite-forgotten 6502 high-level language

Six Early Games (FBOK):



HUEY (HP-style calc):

11 Games:

6502 SBC high-level languages:

6502 Tiny PILOT:

C’MON & Lil’ Bug for PAL-1:
Melody Maker & Music Box:


Johnson McShane brochures

Johnson Computer was an important distributor of KIM-1 products, for MOS Technology, Microsoft and more. Previously they used the name McShane.

It was the firm who brought Microsoft Basic for the KIM-1 to me, see the KIM-1 manuals for their KB-9 document

Documents contributed by Kevin Johnson (of Johnson Computers) via Dave McMurtrie.

Johnson Computer Ads
McShane MOS documents


MOS Technology KIM-1 Brochures and Newsletters

Brochure KIM-1
Commodore KIM-1 Commercial
KIM-1 brochure
kim-1 order form
KIM-1 Product Brochure
MOS Technology brochure
MOS Technology newsletter February 1976
MOS Technology April 1976 customer update
Customer Errata Letters
Customer Errata Letter 1
Customer Errata Letter 2
Customer Errata Letter 3

MTU K-1008 Visable Memory

All about the MTU K-1008 Visible Memory: documents, programs, images, videos and replica, you find it here.
The MTU K-1008 is an 8K memory and video display board. Part of the MTU family of card cages and RAM/ROM boards, around 1978 for KIM-1, SYM-1, AIM 65. Later also for Commodore PET systems.

I have some K-1008 information on paper as Fall Catalog and K-1008 User manuals of MTU, the listings in the Graphics software Package and hires photos of the board.

Triggered by Dave Plummer, who owns a K-1008 and made some demo programs I added this spring the K-1008 as peripheral to the KIM-1 Simulator.
A basic working version, with memory settings as the original. A 6502 program in the simulator could fill the video display.
Dave made nice youtube videos about his KIM-1 system with MTU cards in a card cage, see Dave’s Garage.

Then Eduardo Casino, of KIM-1 Replica fame, started to design a replica, including an expansion bus. He motivated me to enhance the Simulator.

Eduardo also OCR’ed and typed in the Graphics Software Package programs for the MTU K-1008. I played with the sources and coupled the text display programs to Microsoft KB9 Basic.

He made a quick and dirty binary image to show on the K-1008 video display. I took his idea and added a facility to the Simulator to load any image to the K-1008.
This requires the use of GIMP, the image handling program, to create intermediate black and white 320×200 files as ‘C header files’.
These C header file can be imported in the Simulator and shown on the display. A command line utility LoadK1008 converts these C header files to a binary image in K-1008 format.

All this required a page with all the K-1008 information: documents, programs, images, videos and replica, you find it here.

Update 10 september: Eduardo Casino has made available his work on the Graphics Software Package: OCR’ed manual, listings, sources, binaries made with 64tass assembler.

KIM-1 Simulator 1.3.0 -> 1.3.4

KIM-1 Simulator 1.3.x adds the improvements from the 1.2.x branch to the V1.1.8 branch.

NEw improvements also: bundled with the also recently updated Convert 8 bit Hex formats program and the SST switch now turns on the built-in debugger!
1.3.1 Adds refresh of K-1008 memory with File/tapeload and debugger refresh.
1.3.2 Load C header image files into K-1008 video display, and command line utility to convert C header file to K-1008 binary
1.3.3 Adds a more realistic aspect ratio variant of the K-1008 display besides the simpler and therefore faster ones.
V 1.3.4 August 31 Read text file to console improved, improved K-1008 settings

Have fun with this release and as always: keep me posted of wishes and bugs.

You may ask, but this will never be more than a simulation and not a real KIM-1 emulator, many First Book of KIM programs that manipulate the LED displays will not work in this simulator architecture. TTY programs work well. Use the debugger!



VKIM is a KIM-1 emulator written for the Palm OS.

A Basic KIM-1 is emulated. With tape I/O, program load or save. Source included.

I do not own a Palm. But a PALM can be emulated. An excellent browser based one is CloudPilot .

You need a Palm OS ROM and VKIM. I packed PALM OS 5 ROM and the application VKIM in this archive.

The vKIM program emulates a M6502 processor with approximately the resources of a KIM-1: it has a keypad and display, 4 Kb of RAM (the standard KIM-1 had 1 Kb), 2 Kb of ROM containing a patched version of the ROM on a KIM-1 (more on that in a bit), 128 bytes of RAM at $1780-$17FF, and a simulated TTY. The I/O and timer resources of the two 6530 support chips are not emulated.

The interface that is implemented on the keypad is identical to the actual KIM-1 interface — because it is implemented by the KIM-1 software.

As a convenience the NMI vector at $17FA-$17FB and the IRQ vector at $17FE-$17FF are automatically set to $1C00 when vKIM is initially started, and when the “Clear all RAM” menu option is selected.

Emulated RAM is cleared only by explicit action — when vKIM is exited all RAM is saved, and restored when vKIM is restarted.


The standard KIM-1 keypad is the interface that vKIM displays when started up. Since the use of this keypad is entirely a matter for the KIM-1 documentation, I will mention only the differences here. First, the SST switch has been replaced with a checkbox. When checked, SST mode is active; unchecking the box is equivalent to turning the SST switch to the “off” position. Further, as a convenience the locations $00EF-$00F5 are fomratted and displayed to the left of the keypad when SST mode is active.

Finally, there is a button labelled “TTY”. When this button is pressed, the keypad disappears and the TTY interface is displayed.


When TTY mode is selected (by pressing the “TTY” button on the keypad screen) a “TTY” emulator is displayed. This display includes “CR”, “LF”, and “Rubout” buttons, since these are not readily available through Graffiti input. All other input, however, is to be entered in the Graffiti area. As a convenience to the user (and to emulate the limitations of a real TTY) lower-case alpha input is translated to upper-case before being sent to the emulated KIM-1. As a result, it is not possible in the current version of vKIM to enter lower-case data to the emulated KIM-1. Feedback on whether this is a hardship will be taken into account for future releases.

Also, as a convenience a Rubout character is automatically generated when entering TTY mode. Thus, the “KIM” prompt will appear as soon as TTY mode is entered, without requiring the user to press “Rubout” first (as on a real KIM-1).

Finally, there is a button labelled “Keypad” which will return the program to the keypad interface.

Under the “File” menu (press the Keypad label e.g.) are:

* “Create vTape…”
Saves which saves a copy of a specified range of addresses to a simulated or “virtual” tape;

* “Load vTape…”
Restores saved data from a vTape back into RAM (at the same location it was saved from);

* “Delete vTape”
Deletes a saved vTape;

* “Import…”
Loads data into RAM from a Memo Pad entry. The memo bust begin with “; vKIM”, and be followed by data in either dump format, or the paper tape format described in Appendix F of the KIM-1 User Manual. (Samples of both formats are shown below.)

Under the “Edit” menu are:

* “Copy block…”
Copies a block of data from one location in memory to another (no special provision is made for overlapping source and destination);

* “Clear block…”
Sets a specified range of addresses to $00;

* “Clear all RAM”
Sets all of RAM (including the block at $1780-$17FF) to $00, except for the IRQ and NMI vectors, which are set to $1C00;

* “Restart”
Emulates a processor restart.

Under “Ref”

* “Locations”
Lists system-use locations in page zero.

Under “Options”

* “Preferences”
Does nothing. Essentially a placeholder for options that may be implemented in the future.

* “About vKIM”
Gives information about the version of vKIM, and distribution information.

Import formats

Sample of of a memo pad item in “dump format”:

;vKIM BAGELS from First Book of KIM
0200 E6 16 20 40 1F D0 F9 D8 A9 0A 85 18 A9 03 85 10
0210 38 A5 13 65 16 65 17 85 12 A2 04 B5 12 95 13 CA
0220 10 F9 A6 10 A0 C0 84 11 A0 06 C5 11 90 02 E5 11
0230 46 11 88 D0 F5 18 69 0A 95 00 C6 10 10 D2 C6 18
0240 30 7A A9 00 A2 0C 95 04 CA 10 FB 20 CE 02 F0 FB
0250 20 CE 02 F0 F6 A5 08 F0 08 29 60 49 60 F0 A9 D0
0260 DD 20 6A 1F C9 10 B0 E3 C9 0A 90 DF A8 A6 10 E6
0270 10 B9 E7 1F 95 04 98 D5 00 D0 03 E6 0E 8A 95 0A
0280 A5 07 F0 31 A0 03 B9 0A 00 29 18 F0 12 B9 00 00
0290 A2 03 D5 0A F0 05 CA 10 F9 30 04 E6 0F 16 0A 88
02A0 10 E4 A2 01 B4 0E B9 E7 1F 95 08 CA 10 F6 20 CE
02B0 02 E6 0F D0 F9 20 CE 02 D0 FB F0 8F A2 03 B4 00
02C0 B9 E7 1F 95 04 CA 10 F6 A9 E3 85 08 D0 E0 A0 13
02D0 A2 05 A9 7F 8D 41 17 B5 04 8C 42 17 8D 40 17 E6
02E0 11 EA EA 88 88 CA 10 EF 20 40 1F 60

Sample of of a memo pad item in “paper tape format”:

;vKIM sample ptape format


Me and my KIM-1

My first computer is a KIM-1. Still have it! A life changing experience!

This is the story of me and the KIM-1.

Philips educational kits.

As a young child, at age 12, I was introduced to electronics with the Philips electronic kits. First a Pionier crystal radio. Easy to build, good instruction manual. Lots of listening pleasure!.

Two years later I bought the Philips EE8 Electronic Engineer kit. Again nice builds (the 8 stands for 8 experiments), with a good manual. Since the manual covered the expansion to the EE20 for 20 experiments, I bought the parts myself one by one at Aurora Vijzelgracht, Amsterdam.
More on the Philips kits on my website dedicated to electronic kits.

Radio Bulletin

In 1978 I bought my first computer, a KIM-1. It turned out to be a Rockwell rebadged Rev F Mos Technology board.

The beginning of lots of fun, learning, member of the KIM gg Club and making and publishing in the dutch electronics magazine Radio Bulletin and the KIM Kenner.

In 2014 the big KIM-1 machine was finally taken down in parts, the following photos showed the end result as in 1985 after many years of tinkering.

The KIM-1 system ended as a real production system until 1985, mainly to write articles, all Radio Bulletin and KIM Club Magazine related work was done with this system.

My KIM-1 workplace in 1979, no video terminal, no printer, hand assembly

My workplace setup in 1982: KIM-1, dual cassette, tv monitor, H14 printer, ASCII keyboard

1984, VT100 as videoterminal, what a progress!

Then a CP/M machine took over (a Spectravideo X’Press 738) with the same VT100 as terminal.

  • KIM-1
  • 8K RAM  in system case
  • 32K RAM in expansion case
  • Two ACIA 6850 serial
  • A PIA/VIA card with two 6820 PIA’s
  • Parallel ASCII keyboard with home made logic circuit
  • Video Display 32×32 uppercase characters on an analog TV
  • Dual cassette tape system with motor control
  • MDCR digtal cassette system in second expansion case
  • Radio Grafisch Display in second expansion case
  • Heathkit H14 matrix pinter, serial with RTS handshake via bitbanging RIOT port
  • VT100 Digital Equipment Video display unit VT100
  • Boot tape to load device drivers and Micro Ade (extended to 8K)
  • MICRO ADE assembler/editor, used for program development and article authoring
  • Microsoft Basic KB9 (not used often, nice study material!)
  • Pascal-M compiler and interpreter (mainly development and experiments, not for production)

First the KIM-1, I still have it, in working condition, in my private museum. Changes still visible, are a red acryl cover over the LED displays, a capacitor moved to the back to make it flat enough to fit the case I made and some supports to have it lay stable and safe on a table.

Why a KIM-1?

In 1977 I was reading in the electronics magazines about the revolution taking place: 8 bit microprocessors!
During my study I encountered Digital Equipment machines, PDP-8 in the lab, PDP-11 in the Mathematic Computer Science department, a Minc in Medical Physics group, my major.
The electronics department where I was doing an intern not only introduced to digital electronics and I helped them to introduce the Z80 to the instruments designed for laboratory experiments.
I learned assembler quickly, PDP-11 was a dream come true, the Z80 a bit of a nightmare but you could do so much with effort.

At the same time I started to write for the magazine Radio Bulletin, simple analog and digital circuits and continued to be an editor until 1987. I met Dick de Boer who was writing his famous Microprocessor articles and introduced the KIM-1 to the Dutch electronic engineers. So a KIM-1 with the very attractive 6502 was the logical choice for my first microprocessor system.

First case: memory, connectors, power supply

A KIM-1 itself was fun to learn with, but it quickly needed more; a permanent power supply, protection, easy to access connectors and interfaces for  a bus to have  more memory.
So the case seen in the next figure was built:

Power hungry, so lots of lineair power supplies with large cooling.

The first case I built from alu profiles contained the KIM-1, a backplane for 6 memory boards, a lot of power supplies (lineair, so heat was a problem!), a patch panel to access the expansion connector, cassette I/O, serial interface and various switches.

PCBs handmade, double sided!

Memory 2K RAM Card, BEM Bus Brutech Variant made by Hans Otten
Memory boards were made myself by drawing with Edding ink on the blank PCB, etching and drilling. Filled with 2102 RAM IC’s for 1K per board, it filled lower RAM of the KIM-1 $0400 – $13FF. The bus is a 31 pin DIN connector, based upon the BEM (Brutech) bus.

I bought two of this deck from Radio Service Twenthe, Den Haag, fascinating electroncis dump store!

The next thing I built was a video display unit. All TTL 74XX logic IC’s, a 2513 character generator, a AY-5-1013 character generator, an ASCII keyboard, display on TV 32×32 characters uppercase. RS232 input/output to the KIM-1.
On top of the VDU a dual cassette deck is shown. From the famous Dutch dump shop Radio Service Twente two audio cassette decks were bought, some audio amplifiers and power supply added, and a remote control circuit via a 6532 GPIO line (standard as in Micro Ade). Served me well for many years, in 2014 the decks strings were dried out and crumbled after many years of not being used.

Next was a real expansion cabinet with a long backplane for 32K memory with 8x 4K RAM card, 2114 based, Designed by me, published in Radio Bulletin and sold by Visser Assembling Electronics. BEM bus compatible.

4K SRAM card

4K SRAM card, Radio Bulletin September 1979 part 1  part 2

Production 4K RAM card

Prototype 4K RAM card, also hand drawn on the PCB!

In the expansion cabinet three slots were added for I/O. Two cards were designed by me and published in Radio Bulletin: an ACIA card for two 6850 Motorola ICs, and a PIA card for two PIAs, 6522 or 6520 or 6820 or 6821. I never used more than one ACIA and one PIA card. Shown are the prototype cards, in the article production quality PCBs were used.

PIA and VIA card design by Hans Otten June 1984 Radio Bulletin

ACIA Motorola 6850 by Hans Otten, 1983 Radio Bulletin

On one of the ACIAs a VT100 Digital Equipment terminal was connected, taking over from the bit banged serial interface and the homebuilt video display. ON the other ACIA a Heathkit H14 matrix printer was added, a mediocre but adequate printer.

Together with Micro Ade as assembler and editor, the dual cassette deck, 40K RAM In total, this was a nice machine! Until 1987, when I bought the Spectravideo X’Press 738 MSX and CP/M system, used for all my publishing activities.

A third expansion cabinet was built around 1983. It was driven by the PIA’s, the Radio Bulletin Grafisch Display was inside the cabinet, along with two MDCR Philips Digital cassette recorders, alo published in Radio Bulletin. The speed difference between Hypertape audio cassettes and 2400 baud MDCR speed was not that impressive.

Dirk Dral

EPROM card (Dirk Dral)