Wozniak's Original System Description of the Apple ][

CowboyRobot writes "Opening with the line, 'To me, a personal computer should be small, reliable, convenient to use and inexpensive,' Steve Wozniak gave his system description of the Apple-II in the May, 1977 issue of BYTE. It's instructive to read what was worth bragging about back then (PDF), such as integral graphics: 'A key part of the Apple-II design is an integral video display generator which directly accesses the system's programmable memory. Screen formatting and cursor controls are realized in my design in the form of about 200 bytes of read only memory.' And it shows what the limitations were in those days, 'While writing Apple BASIC, I ran into the problem of manipulating the 16 bit pointer data and its arithmetic in an 8 bit machine. My solution to this problem of handling 16 bit data, notably pointers, with an 8 bit microprocessor was to implement a nonexistent 16 bit processor in software, interpreter fashion.'"

Re:Almost, Apple...

[NixieBunny]

I was in high school working in a retail computer store in 1978 when the Apple ][ and its competitors were taking hold in the market. The Apple was the only computer with high-resolution color graphics for under $5000. I could tell just by looking at its motherboard that its design was something special - having built a video display board from scratch with my brother, I knew how much circuitry is usually required.

Man was an F'ing Genius

[Nitewing98]

Woz WAS the SH*T back then. While I still love him, he's never been the same since the plane crash. God knows what he might have come up with to save the Apple II if he hadn't had the accident.

6502 was awesome!

[Anonymous Coward]

I wrote a number of utilities for the Apple ][. One of which was a replacement garbage collection utility. The garbage collector in the Apple ROM would basically kick off when there was no more available memory and then "freeze" the machine for about 30 minutes while it dumped the garbage. I wrote one that could be run from the Ampersand &GC in Applesoft Basic. If your application used a lot of strings and reassigned those strings the heap would fill up really fast. My utility would run in seconds as opposed to the 30 minutes. I made about $1000 as a 16 year old kid selling this utility in Nibble magazine.

One other comment. Woz was a genius, but his shortcut for color graphics was based on 7 lines. Each byte in the $C000 address space used a nibble encoding scheme to display color. $C000+$200 (I think would move to the next line 7 pixels down. This 7 byte math drove us developers nuts. To draw on the screen you would either use FP math (very slow) or you would pre-populate a look up byte table to know where in memory you should poke to get the right row to show up a color.

I've not done assembly language since those days. It sure was fun and challenging though. Now everything is so bloated I rarely see tight efficient code anymore. I'm not suggesting that we go back to developing in assembly. I'm just pointing out that you were forced to be disciplined when you coded which made for more efficient code.

Re:Mistake

[Purity Of Essence]

Here's the very strange thing about that error. I have a scan of that issue of Byte and it does indeed say 553 there. The article also has a circuit diagram, again showing a 553. If you look at the original Redbook schematics, it also shows a 553 quad timer. There is even advert for 553 quad timers on page 174 of that issue of Byte. I've also seen a post online from someone with a 553 chip in an apparent timer circuit asking about it's identity. All that and no datasheet or cross reference for a 553 quad timer can seem to be found. My best guess is 553 comes from an imprinting error on actual 558 chips.

Re:Almost, Apple...

[sensei moreh]

Apple pricing at the dawn of the PC era (Fall 1981), when fresh out of graduate school, the university that hired me offered me $10K in start-up funds for my research lab. I knew I wanted a microcomputer system, but didn't know if the newly-introduced IBM PC was going to be anywhere nearly as well-supported as the Apple ][. So I took that $10K and bought an Apple ][+ with 64K RAM, a Z80 card, CP/M, 3 floppy drives, a monochrome (green) monitor, a color monitor, an Epson MX80 dot matrix printer, a Diablo daisy-wheel printer, Apple Pascal, Microsoft Fortran, and Wordstar. I think there were even a few dollars left over. The next spring, I decided I wanted system for myself so I spent $2200 on a Basis 108 (a German-made Apple ][ clone with a built-in Z80 card and a monstrously heavy case) with 2 floppy drives and a monochrome monitor.

Woz?

[pbjones]

So are we seeing more Woz articles because he is moving back into the computer limelight, or are we just using him to fill a gap in the news?

Re:Mistake

[Anonymous Coward]

Woz came up with so many improvements over previous art: cutting edge stuff. As you have noted: Video retrace DRAM refresh, well designed interpreted Sweet-16, very efficient BASIC, group encoding for the floppy disk, color shift without subcarriers.

Not rocket science? That is VERY conservative science. No place to innovate at Woz's pace. There was little, if any prior art: Microprocessors were just too small for "serious study" in most institutions. Woz was, and has always been the king of the tech inventor/implementors.

No body, but nobody came up with so many improvements in such a short time.