Tuesday, November 23, 2004

The Creation of the Macintosh

In the early 80's there was a quiet project underway in a small remote building at Apple Computer where a team of engineers and programmers worked tirelessly with a dream of revolutionizing the personal computer into an information appliance that would be "for the rest of us". Even to those of us who were deeply involved in technology at the time, this was an exciting leap forward. Now 20 years have past and this event remains a milestone in personal computing.

Read about this revolution from the inside, from original members of the small team that caught the imagination of everyone who came in contact with them, including Steve Jobs who championed their cause. Folklore.org is a collection of stories and anecdotes from the designers, developers and programmers who made up this unique team. It is also an interesting look at the dynamics of a startup struggling within a more rigid business culture.

Many of the recountings are written by Andy Hertzfeld who was a cornerstone of the software team. Andy has since taken this to the next level with the publication of a book Revolution In The Valley, the insanely great story of how the Macintosh was made. Click on the link to buy this at Amazon.com's everyday low price and support the operation of this site at the same time!

Friday, November 19, 2004

Apple I/Replica I and FORTH

The Apple I started as a hobbyist's project in 1976, and turned into one of the early catalysts of the personal computer revolution. The simple elegance of the WOZ monitor (only 256 bytes!) and readily available parts made this computer accessible to everyone. Unfortunately, today only a few survive.

Below I have links to the original documentation that came with the Apple I, including the hand typed basic manual and owner's manuals. Browsing these, you really get the feel that this was a hobbyist's project, not the beginning of a billion dollar company!

Apple I User's Guide
Apple I BASIC Manual
Apple fritter
Apple I Owner's Club

Replica I
The Replica I is a single board computer that is a functional replica of the groundbreaking Apple I from the 70's. The primary difference is that some of the parts are implemented with modern components. However, it still uses the venerable 6502 and contains the original Woz monitor and Woz's hand assembled BASIC!

My Replica I is using a standard modern PC power supply, a PS/2 style keyboard, and Apple //c 9" monitor. Some of my projects for the Replica I include creating a program loader to allow easy loading/saving programs to an attached PC, and porting one of my favorite old languages, FORTH, to the Replica I/Apple I.

You can buy a Replica I in kit form or ready built from Vince Briel, a hobbyist and fan of the original Apple I.

Forth is a fast, powerful, and portable high level language that was popular in the early days of micro computing because of its ability to easily manipulate hardware details while retaining many benefits of a high level language. It is a "stack oriented" language and thus maps efficiently to an 8-bit microprocessor.

Forth has a small kernel of "words" that are implemented in the native assembler of the target platform. The balance of the language consists of further word definitions made up of "address" references to these kernel words. In this way, only a small part of the assembler listing is dependent on the host platform, making this a very portable language (even in assembler!).

This is a figFORTH 1.1 port originally distributed by W. F. Ragsdale for the Rockwell AIM65 back in the late seventies. I have taken this listing and made a port to the Apple I/Replica I, resulting in a powerful programming environment for experimentation or computer control applications. FORTH is still popular today and is found in such diverse applications as embedded controllers and PDA's to NASA applications on the Space Shuttle!

FORTH is compact, only 7 Kbytes for the kernel. While fully functional now on the POM Apple I emulator, I still need to implement block storage in memory so that programs can be loaded and saved independent of the kernel itself with the cassette interface. You can download the current version below.

Note: There is currently an issue in the Pom1 emulator that results in ASCII $1F being used to represent [space] where the Apple I/Replica I expect $20. This must be changed in the listing and recompiled depending on the platform you chose to run on.

If you want to learn more about FORTH, The best place to start is Leo Brodie's book Starting FORTH which is conveniently online. Also, if you wish to change my port for the Apple I/Replica I, you will need the CC65 C Compiler and Macro Assembler/Cross Compiler for the 6502. More enhancements to follow...

Micro Chess
One of the most fun things I have done with my new Replica I was to load and run Peter Jennings' original Microchess written in 1976. The excitement of seeing this vintage early program come to life on my just assembled Replica was probably much like early Apple I users back in the 70's would have felt on powering up this landmark program the first time. This program was a wonderful accomplishment for several thousand bytes of code!

Welcome to 8bitsunplugged.blogspot.com

Why old technology and new ideas? Several reasons... First, many of us who have been in this industry for 25 or 30 years are beginning to look back on all the developments over those years and are realizing that there were several key moments in time, pieces of technology, or products that defined an era in computing.
Many of those pieces of technology or products lie at the bottom of land fills today. Others are just being recognized for their significance and are starting to be dusted off and collected, initially by those of us who have a sentimental connection with some of the first machines we were able to call "our own".

The second reason is the low cost of this old technology. Atari, Commodore, and Apple ][ computers can often be had for less that $10 on eBay and make a great starter for learning machine language programming or for just hardware hacking.
A third reason, and I think one that leads to much of the interest in vintage computers, is because technology advancement is moving so fast, many of the older computers never reached the potential of their full capabilities. Many of us moved on to MS DOS and Windows long before we had exhausted the possibilities of our old favorite Apple ][, Atari, TRS-80 or Sinclair computers.

The final reason I see, and one interesting to me as an electronics hobbyist, is the apparent resurgence in the basic microprocessor. I'm not talking about the 64 bit Itaniums and the like, but rather, the explosion of embedded processors and microcontrollers on the market. The 8-bit CPU is finding a new home in everything from your dishwasher to your vacuum cleaner. These are simple processors usually dedicated to performing a single task.

MicroChip PIC's, Zilog Z8, ARM, Parrallax Basic Stamp, and many others are filling this space. One of the most interesting and powerful of these is the Z8. It is one of my favorites because it still compatible with Z80 source code from the 70's and early 80's. The basic stamp is simple to use and a lot of fun too. Many have equated the power of the Basic Stamp to an "Apple ][ on a chip". What's more, most of these microcontroller chips cost less than $15!

This site is dedicated to fans of old computers, hobbyists, and engineers who appreciate the power and simplicity of yesterday's and today's 8 bit microprocessors/microcontrollers, or who just like tinkering with vintage technology!

November 2004