Daves Old Computers - ALTAIR 8800

This package is my attempt to preserve a detailed record of my Altair 8800 computer. For those who are not familiar with the name "Altair", the Altair 8800 is considered to be the first "personal" computer - Although this title has been the subject of some debate and controversy (Several other small and functional computers did exist prior to the Altair), I believe the title is deserved because:

H. Edward Roberts, the creator of the Altair says its even simpler than that: "We coined the phrase Personal Computer and it was first applied to the Altair, i.e., by definition the first personal computer." ... "The beginning of the personal computer industry started without question at MITS with the Altair."

I have been involved in the computer industry since the mid 1970's, and have always had a keen interest in "personal" machines. In the early years I built several small homebrew designs, and knew a few other people doing the same using such early microprocessor chips as the Intel 8008 and the RCA 1802. I know of at least one individual who built a functional CPU from TTL logic! A clear memory of mine is that the Altair was the first commercial machine I ever saw in someone's living room.

It is said that imitation is the sincerest form of flattery, and shortly after the release of the Altair, Mits was "flattered" by the first personal computer clone, the IMSAI 8080.

I have the good fortune of owning an original 1975 Altair 8800 - my machine is the first release - Not one of the later A or B models. It has been in my possession since the late 1970's, is in very good condition and remains fully functional.

In its earlier years, this machine was instrumental in the development of my skills and career path in the embedded software development tools industry. My first assembler was written on this machine, as was my first debugger, disassembler, text editor, BASIC interpreter, and even my first Operating system. I learned so much with this machine that it is impossible to give a full account.

In more recent years, this machine has spent most if its time sitting quietly in a corner of my, basement, lovingly crated up in a padded box. At rest but not forgotten. I have recently had occasion to unpack it and bring it to life again, a most wonderful excercise in nostalgia. The diskettes are filled with treasures from my early computing years.

It occurred to me that this machine and its content are quite irreplacable, and that it's amazing that 25+ years diskettes still read in a 29 year old computer.

This package is an attempt to "digitally" preserve my Altair, both in the form of pictures and scanned documentation, as well as in images of the diskettes and a fully functional simulator. With this package, anyone can actually "boot up" my Altair, and use it exactly as it was years ago.

After starting the project, I began looking and found material on the web including many photos and a couple of other Atlair simulators. This project differs in that it attempts to document a specific Altair (mine), and concentrates more on recreating a usable environment than it does on recreating the flashing lights on the front panel.

NOTE: The simulator and tools are primarily designed to be activated from a command line interface (such as DOS or a Windows DOS box). If you are not comfortable using such an interface, then you probably will not find this material very interesting (And you definately would not have liked the Altair - or any other computer from that era). I have tested the enclosed tools under DOS 5/6, Win95/98, Win2000, WinXP and Linux DOSemu.

History of my Altair 8800

In the late 1970's, I was attending the University of New Brunswick. I had entered the university in the Electrical Engineering department, however I "fell in love" with the schools IBM 360 mainframe computer, and changed my program to Computer Science.

During my first year, I met Gary Morrison, a graduate of the school, who was working in the computing center as a systems programmer. Gary could answer *most* of my questions about the innards of the IBM system and its software, and occationally sneaked me access to facilities not normally available to mere students. On top of that, Gary *HAD A COMPUTER OF HIS OWN* - A handbuilt "wirewrap" 8080 machine with front panel switches and 256 bytes of memory. It was wonderful - I had to have one - Gary let me work with his.

I found a cross assembler on the UNB mainframe, developed a rudimentary 8080 monitor program, and figured out to program it into a 2708 EPROM (a process which involved punching a tape in the UNB center, then reading the tape through an ASR33 teletype into an eprom programmer in the EE lab). Gary wrapped on an 8251 UART, and after a couple of trys we had the machine talking to our own teletype! Now I **REALLY** had to have one.

Gary and I became friends and eventually ended up sharing a house. One day Gary came in and said "Guess what - there's a guy in town selling an Altair". I had heard about these wonderful machines - we had to go see it. There it was: This beautiful big box will a panel full of lights and switches. It had a DISK DRIVE, a MODEM and a few *K* of memory! It also had this cute little blue ADM-3A terminal that we eventally came to refer to as the "toilet-bowl terminal" (something about its shape) - this would be *WAY* better than a mechanical teletype.

Dan Clarke had bought and built the Altair but decided after a couple of years not to keep it. He did a good job on the construction because in all this time I have not had any assembly related problems. (Dan didn't like the silver "ALTAIR 8800" plate which goes across the bottom of the front panel, so he hadn't installed it. I don't recall if we got the plate from him or not, but it never did get installed). Dan has kindly written some notes on his experiences with the Altair.

It was love at first sight - but I was a poor student. Fortunately, Gary was gainfully employed and the machine decided to come home with us. Thus began my long relationship with this wonderful machine. Many an evening and weekend was spent in front the "toilet bowl".

I lost sight of the Altair briefly when Gary moved to Ottawa during my final year and took "his" machine with him. When I left university, I also moved to Ottawa, and once again could visit the Altair on a regular basis. Not long after that we found another S-100 machine (A big black Cromemco Z2) which Gary took a fancy to, and the Altair finally decided it was time to settle down with me for good.

Gary kept the ADM-3A to use with his Cromemco, and I picked up a Cybernex terminal for the Altair. Several years later, the ADM-3A packed it in and Gary asked me if I wanted it before he threw it out. Of course the answer was YES. I repaired the terminal and it has been back with the Altair ever since (the Cybernex is long gone).

The Altair did change from time to time over the years - at one point I managed to obtain an actual MITS disk enclosure (empty unfortunately) and transplanted the floppy drives from their original individual enclosures (visible in the oldest of the pictures) into the MITS enclosure. A 64k RAM card was added (unfortunately the original 1K, 4K and 8K cards were given away), and I constructed my own serial card to provide extra I/O ports to drive a Heathkit printer. Probably the largest "addition" was a Pertec 9-track tape drive. Rather than bring all the wires from the drive to the Altair, I built an interface card that mounted on the drive, and a simple 8-bit bus interface into the Altair. The tape drive is long gone, however I still have the Altair interface card. (Both the tape drive and the printer can be seen in a couple of the pictures - the large grey box on the floor under the printer is a 300 bps modem!)

At one point I acquired an aftermarket Z80 CPU card which had support for the Altair front panel - I thought it would be neat to be able to use the extra Z80 opcodes, however installing the card would have required that I change the front panel connector which would prevent me from easily switching back to the original 8080 CPU, so I decided not to install it. Some time later I met another Altair owner who wanted the Z80 card and did not care about changing his machine - I gave him the Z80 and he gave me his original 8080 CPU card, so now I have a spare. I also picked up an extra MDS disk controller somewhere along the way.

For the past 15 years, this machine has been packed away in a crate in my basement. I have dug it out and fired it up a couple of times during this period, but it has not seen daily use for some time. This past christmas (2003), my wife decreed that I would not go up to my office (home office located over garage) during the holidays, and that I would not work on business projects.

So.. Once again I went to the basement dug out my Altair... With a little cleaning it booted right up (always has!). Poking around the diskettes, I discovered that much of my early software and source code was still intact - thats when I got the idea to create this "digital museum" of my Altair.

Some interesting notes on my Altair

My original Altair executes about 350,000 instructions/second. My simulator runs at better than 50,000,000 8080 instructions/sec on a PIII/733 - such is progress, but it comes at a price - I have never enjoyed another machine as much as I did my Altair. (note that I have added a /P option to allow the simulator to emulate the actual Altair performance).

With this package, you can experience my Altair, you can look at all the hardware, read the documentation, and even USE the thing if you feel so inclined - Enjoy!

A second Altair 8800 in my collection can be seen on my S100 page.

Altair Photo Gallery

Photos of Complete System
Photos of Main Unit
Photos of Disk Unit
Photos of S-100 Cards
Photos of Adm3A terminal


Altair documentation
My Altair Simulator - experience using my Altair
Rich Cini's Altair32 simulator

Misc. Material

1976 Price List
A little Mits history
Altair Technical Information (3.6M PDF)
Altair Technical Notebook (1.7M ZIP/JPG)
Altair brochure: Cover, Page1, Page2
Mits-Mas Christmas Catalog - From Dec75 byte (4.6M PDF).
Mits 1st Altair Convention Notice (1976)
Assembling an Altair - From Dec75 Byte (150k PDF)
NorthStar Micro-Disk advertisement from Jan 77 Byte (78k JPG)
NorthStar Brochure showing Micro-Disk system (130k JPG)

Mits advertisements: Created by Man, Land of Altair, Inside Altair, Limited Time, Santa, Can Anyone Beat, Inexpensive BASIC, Report II, Napoleon, Unusual places, Ben Franklin, Painting, Altair family, Off Shelf1, Off Shelf2, Imagine, /ability, Christmas Plan, Good thinking, One and Only, Altair 4K, Address Circitry.

Acknowlegments and Thank yous

H. Edward Roberts - Founter of Mits, Creator of the Altair, Father of the Personal Computer.
For creating the Altair in the first place, and for granting permission for me to share the Mits material.
Dr. Charles Grant - Co-founder of NorthStar Computers Inc.
For granting permission for me to share the NorthStar software and documentation.
Richard Cini - Maintainer of the Altair32 simulator and documentation archive.
For maintaining the Altair32 simulator, and for having already scanned in some of the large Mits documents.
Alan Bowker and Peter Midnight - Former employees of NorthStar Computers
For providing much useful information, and helping me contact Dr. Grant.

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Copyright 2004-2005 Dave Dunfield.