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Wozniak's Original System Description of the Apple ][

Posted by Soulskill on from the no-you-don't-eat-it-listen-to-me dept.

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.'"

23 of 170 comments (clear)

  1. Mistake by AmiMoJo · · Score: 4, Informative

    Spot the mistake on page 40: the timer used was a 558, not a 553.

    I re-implemented this system for a project to connect old game controllers to USB. It is low cost and works remarkably well for basic gaming.

    --
    const int one = 65536; (Silvermoon, Texture.cs)
    SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
    1. Re:Mistake by Anonymous Coward · · Score: 4, Informative
      Yes. There are so many people that labored in obscurity that are far more deserving of praise. You want "brilliant"? Try the MIT Rad Lab series. Or Englebart, or Sutherland.

      http://en.wikipedia.org/wiki/Ivan_Sutherland

      http://en.wikipedia.org/wiki/Douglas_Engelbart

      http://en.wikipedia.org/wiki/The_Mother_of_All_Demos

      http://en.wikipedia.org/wiki/Radiation_Laboratory

      http://en.wikipedia.org/wiki/J._C._R._Licklider

      Somehow, some guy plugging a resistor to a 555, as described in the 555 datasheet, fails to amaze in comparison.

      I'm just sick and tired of the continuous hype for Woz when the people who actually invented computing are forgotten.

      Your mind should be blown by people who invent entire concepts from thin air.

    2. Re:Mistake by CanHasDIY · · Score: 3, Insightful

      Getting back on topic, has anyone started a petition to get the other Steve back as head honcho at Apple?

      Shit, that happens, let me know.

      With Woz at the helm, I may just be forced to reconsider my Apple boycott, walled garden or not...

      And you'll probably be able to augment your iPhone via 6 PCI slots or one of 20 ports...

      You say that as if it's a bad thing....

      --
      An enigma, wrapped in a riddle, shrouded in bacon and cheese
    3. Re:Mistake by Purity+Of+Essence · · Score: 5, Interesting

      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.

      --
      +0 Meh
    4. Re:Mistake by Chris+Mattern · · Score: 3, Insightful

      Let me know too, I'll want to short Apple stock. Woz is a pretty good tech head but as a businessman he's a disaster.

    5. Re:Mistake by slew · · Score: 5, Insightful

      The 555 stuff isn't really that amazing, but Woz did some fairly amazing things. For example...

      Integrating the dram refresh with the video display on the original Apple ][ was pretty clever as with the 1/2 phase pixel shift to get cheap color w/o fancy sub-carrier modulation.

      The original Apple ][ floppy drive subsystem using "raw" drive mechanims from Shugart and implementing the controller mechanism in 5 chips and some software (soft sectored avoiding the punch hole detector, no track0 detector, no head load solinoid, 5/3 software group-coder allowing 13-16 sectors/track instead of 10 when others were using MFM, etc.). This when other vendors at the time had quite inferior, yet more expensive floppy disk drives.

      Sure it isn't rocket science, but it is still good engineering wizardry, not just "plugging resistors".

    6. Re:Mistake by bryan1945 · · Score: 3, Funny

      I'm just sick and tired of the continuous hype for technologists when the people who actually invented math are forgotten. :D

      --
      Vote monkeys into Congress. They are cheaper and more trustworthy.
    7. Re:Mistake by Anonymous Coward · · Score: 3, Interesting

      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.

    8. Re:Mistake by slew · · Score: 5, Insightful

      ??? Mr/Ms AC, I didn't change any examples, that was my first post. Perhaps you are refering to another poster?

      I can't speak for anyone else, but my first statement of my post was "The 555 stuff isn't really that amazing" and I finished with "Sure it isn't rocket science..."

      Do you have some issue with these statements?

      Or are you (Mr/Ms AC) just so filled with Woz hate that you have to attack everyone that says anything even remotely positive about Mr Woz with a hair trigger post? Are you're pissed that he wasn't eliminated before your favorite Dancing with the stars celebrity? Fan of Holly Madison, or a GoGo's fan maybe? Is that why you are posting AC? ;^) ;^)

      Of course Mr Woz isn't god (despite what some OTHER posters may have gushed about), be he seems to have been a damn good engineer. However, sometimes the best role models for people are not the ones that are so beyond us that we can never aspire to be them (scientists or researchers that create a new paradigm), but maybe for some of us lowly engineers, someone that we hope we can hold a candle to on a good day and thus more relateable and a bar that we might be able to reach some day if the stars align...

      Is it literally too hard for you to let people have their own heros instead foisting yours upon others? Something to think about Mr/Ms AC...

      But to answer your question (if it was directed to me and not the other poster), what Woz did with the 55x timer is very vanilla and probably could be copied out of a fairchild or national app-note, but what Woz did with the disc controller was something that pretty much was wizardry. Basically he single handedly designed a amazingly cheap floppy disc controller (40 chips vs 5 chips) that not only was more advanced in storage capacity and access speed than any other in the industry at the time.

      By doing so allowed Apple to sell a disc drive for under $500 with a BOM of $150 (eventually reduced to $80) enabling Apple to practically mint money with this product. In several interviews with Mr Jobs and other Apple and (some disbelieving) Shugart contemporaries, they credit this floppy disc controller design by Woz as the major growth driver at Apple and probably more important than the computer itself in launching the Apple IPO. Basically, Woz didn't have any background in floppy disc controller theory, he read some data sheets and figured it out and beat out the best in the industry at the time. He also layed out the controller circuit board to minimize the feedthroughs to help improve the reliability and manufacturability, basically a soup-to-nuts holistic designer. That's engineering wizardry (to me anyhow, as a lowly engineer)... something I might aspire to someday... But even the best designer needs to crank out a 55x-esque circuit sometimes. I'm sure all you your heroes had a few more pedestrian accomplishments along the way too.

  2. Almost, Apple... by jmerlin · · Score: 4, Funny

    To me, a personal computer should be small, reliable, convenient to use and inexpensive,

    Small, check.
    Reliable, check.
    Convenient to use, check.
    Inexpensive... whoops.

    1. Re:Almost, Apple... by NixieBunny · · Score: 4, Interesting

      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.

      --
      The determined Real Programmer can write Fortran programs in any language.
    2. Re:Almost, Apple... by lord_mike · · Score: 5, Informative

      At the time the Apple II was released, there were only two other non-kit microcomputer systems available--the Radio Shack TRS-80 and the Commodore PET. Both models were well $1000, while the Apple II was about twice as much for equivalent memory. Of course, the Apple II could do a lot more than the other two systems, especially in regards to graphics. However, as the technology improved, and competitors offered more powerful systems at lower prices, Apple never reduced their prices. At the peak of the microcomputer golden age, an Apple II system cost nearly 10 times as much as an equivalent Commodore 64 system.

      When Apple released their floppy disk drive, they priced it at $550. People asked why they priced it so high. Apple responded, "Because we can."

    3. Re:Almost, Apple... by tlhIngan · · Score: 5, Insightful

      Macs price competitive for the hardware?

      Dude, what planet are you on? Let me guess, one with a bite taken out of it?

      Depends how you compare. If you're trying to compare say, a Macbook Pro with a netbook, then yeah, Macs are more expensive. Or even a Macbook Air against a netbook. Ignoring stuff like an Atom is no way competitive to a Core2Duo, nevermind the i5, the SSD, memory, etc.

      OTOH, if you try to compare like with like (as much as possible), they're quite competitive. The usual explainations for deviations is use of cheaper bigger heavier laptops in place of svelte ones (e.g., trying to compare a MBP against some much heavier, much larger Dell model instead of using Dell's more expensive smaller and more portable ones).

      And displays as well - some fail to account for upgrading a 15" laptop from a 1366x768 display to I think the 1440x900+ that Apple puts in the 15" (nevermind the 1920x1200 on the 17")

      Heck, even the Air is standing on its own compared to the Ultrabooks Intel's trying to bring out (hint: they're all a joke. First pass - no manufacturer wanted to make an ultrabook because they couldn't be competitive. Second pass - with Intel subsidies, they got the price to be the same as the Air, but with specs that were iffier (i3 vs. i5, slower, heavier, etc). Third pass (current) - intel relaxed the specs even more to be far more generous - so you can find 14" ultrabooks that are 1" thick or so - basically "small laptop').

      Of course, this holds true pretty much for the first couple of months of Apple's refresh cycle. After that, it's not competitive anymore. Given the current Macbooks are all needing refresh, they are uncompetitive. Once Apple releases their Ivy Bridge laptops (WWDC?) they'll be competitive again. It's because Apple doesn't drop their price as time goes on nor do they have sales.

    4. Re:Almost, Apple... by Ihmhi · · Score: 3, Funny

      He's referring to modern Apple hardware, which some might call "overpriced."

      While others might call it "rape."

      Come on now, be fair. How could you "rape" someone with Apple hardware? Let's compare an iPhone to, say, a vibrator.

      A vibrator is sleek, metallic, vibrates, and can be shoved up your ass. That's completely different from an iPhone which is sleek, metallic, vibrates, and can be-

      Mother of god.

      --
      Random Thoughts From A Diseased Mind (Not For Dummies)
    5. Re:Almost, Apple... by sensei+moreh · · Score: 3, Interesting

      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.

      --
      Geology - it's not rocket science; it's rock science
    6. Re:Almost, Apple... by CityZen · · Score: 4, Informative

      You should look at oldcomputers.net for this info.

      Radio Shack TRS-80:
      basic unit with 4K RAM and B/W video monitor: $600
      basic unit with 16K RAM and Level II basic, monitor: $1000
      ($300 Expansion Interface required to add more than 16K memory)
      basic unit with 16K RAM, Level II, Expansion Interface, monitor: $1300
      5.25" disk drive (requires 16K, Level II, Expansion Interface): $500

      Commodore PET:
      PET 2001 (4K RAM, built-in B/W monitor): $800
      (not especially upgradeable memory-wise)
      PET 4032 (in 1980; 32K RAM, built-in B/W monitor): $1300
      CBM 8050 dual floppy drive (in 1980): $1700

      Apple II: (in 1977)
      Basic unit with 4K: $1300
      Basic unit with 16K: $1700
      Disk II floppy drive with controller card (1978): $600

      Atari 800: (in 1979)
      Basic unit with 8K: $1000
      (includes slots for 3 optional 16K RAM cartridges)
      810 floppy drive: $600

      Exidy Sorcerer: (1980)
      basic unit with 8K RAM: $900
      basic unit with 16K RAM: $1150
      S100 Expansion Unit: $420
      Video Disk unit (B/W monitor + 2 floppy drives): $3000

      Note that prices came down over time, especially due to decreases in RAM prices.

      So, I'd say that there was something of an "Apple tax" even back then, but it wasn't really so much. When you considered how much expansion capability you got with the basic unit (which for other systems was either an add-on or simply not possible), it was actually a good deal.

  3. Re:1977 was a seminal year by Anonymous Coward · · Score: 3, Informative

    The TRS-80 used the Zilog Z80.

  4. Man was an F'ing Genius by Nitewing98 · · Score: 3, Interesting

    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.

    --

    Nitewing '98

    Everything works...in theory.

  5. 6502 was awesome! by Anonymous Coward · · Score: 3, Interesting

    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.

    1. Re:6502 was awesome! by Anonymous Coward · · Score: 4, Funny

      You evil S.O.B. Gimme my $35.

    2. Re:6502 was awesome! by Anonymous Coward · · Score: 3, Funny

      No way. You pirate, you would probably sell my personal information :)

  6. Woz? by pbjones · · Score: 3, Interesting

    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?

    --
    There was an unknown error in the submission.
  7. Re:Woz invented Java! by russotto · · Score: 3, Insightful

    You kid, but in all seriousness, SWEET-16 probably does qualify as prior art for a few dozen currently litigated patent claims. Except you couldn't really call the Apple II "mobile". You could fairly call it a "limited resource computing device", though (a phrase found in one of Apple's iPod patents)