Steve Wozniak Recounts His Efforts to Engineer the Apple II Floppy Disk System
paleotronic.com
paleotronic.com
Woz was intimidated by disk controllers because he didn't know much about them, other than they were big complicated things. So starting with his own ignorance as a fresh slate, he ended up with something better than his former employer HP had in their products.
Sometimes (Sometimes! Not always!) not knowing better can be helpful.
Woz did his thing under much the same constraints as Tramiel held the Commodore engineers to, keep the chip count, and thus the price, down.
Every time Woz added a chip, he carefully looked for very way he could use that chip for different tasks.
Same with the recent Steve Jobs threads. Or any thread featuring prominent programmers or founders.
I think immediately reaching for the "genius defense" (whether deserved or not) does far more harm than good.
Exceptional labels are often used to abdicate responsibility of the mediocre for their own mediocrity.
It's easier to label someone as special than it is to admit you didn't put in the time they did, or that your fear of failure prevents you from trying.
This particular Woz story doesn't scream of "genius" to me.
It screams of curiosity and confidence, a fearlessness, of a young and foolhardy geek swimming in opportunity and it enabled him to discover some interesting, innovative things.
The part where his (probably senior) hardware dept. colleague trolled him into completely ripping apart his work and redoing it all for cosmetic reasons with a single sentence saying "Steve, you mean you’re going to go with less than perfect?" had me laughing heartily, and caused me to reflect on the times similar things had been done to me early in my career.
Not directly related but fun to think about: the word 'interrupt' does not appear at all.
That's actually severely understating the accomplishment. The Disk ][ controller was implemented with like 8 chips, all of them off the shelf TTL things you could get at Radio Shack (OK, two were small ROMs). It talked directly to the drive which needed almost no electronics on it at all. And it was both faster and higher density than all the custom ASICs being sold at the time. It could read bits off the drive at full rotation speed, filling all of RAM within seconds.
For comparison, the Atari 810 drive was designed contemporaneously (though it arrived later to market). It paired a 6507 (6502 with some address lines clipped off), 4k of RAM and a WDC controller chip inside the drive, which then spoke to the main computer over a semicustom UART (or UART-like) chip on the motherboard. And with all that hardware, it managed to deliver the data at 19.2kbps.
This thing was an absolute masterpiece of the era.
- Drive by a floppy controller chip : Controlled by a WDC, Intel or custom ASIC. For example Amstrad, Sinclair +3 or Amiga floppy drives. - Full intelligent : Like Commodore or Atari 8 bit floppy, that carries a computer inside. - Dumb : Like Apple II and I think that IBM PCs.
Full intelligent not was a bad idea when the home computers had these low speeds, as could (on theory), read/write the floppy and at same time do other stuff on the computer. Also, allowed to move the file system implementation and part of the I/O firmware to these embed computer to the floppy drive. But to work nice, need a fast and good connection to the computer. Having a serial communication via bit-bagging as did Commodore, killed it.
That's the excuse, but no. In practice the actual software run on those machines was synchronous. You'd load the game/document, work/play, then save. There wasn't enough space in a 48k world for software complex enough to have background tasks. Honestly the only example I can think of where anyone did anything like this was the animated splash screens during load that some of the later Lucasfilm games on Atari had. And they never would have bothered if the disk was as fast as Apple's.
Also, FWIW: the PC had a "dumb" drive enclosure, but the controller was an ASIC on the motherboard. And it was drivable via a separate DMA chip, allowing true background operation. With 10x the memory of the 8 bit systems, it was not uncommon to find DOS tricks to do background I/O (e.g. RAMdisks were very popular).
I never idolized Woz as a kid back in the 80s, but now I think he's a damn awesome guy.
http://www.computerhistory.org/atchm/apple-ii-dos-source-cod...
http://www.dereferer.org/?https%3A%2F%2Fwww%2Ejwz%2Eorg%2Fbl...
Do browsers today not allow users to set the referrer?
Google and countless web businesses prefix urls and act as "dereferers" so they can collect referers instead of the target websites. There is no shortage of "derefered" links on the www.
A "dereferer" may be useful for a website owner, but is it useful to a user? The "defererer" can track the external sites its users visit, creating a log of users' www browsing, but how does that benefit the user?
For the user, this is sharing far more information with the "dereferer" than with any individual target site.
Is the "Referer" header truly necessary for the user? It is not even spelled correctly.
I have been using the www with target url set as referer instead of referring url for decades with almost zero problems.
The times when a site demands a certain referer are so few and far between that I cannot remember the last time it happened.
about:config network.http.referer.spoofSource
You might get an image of a testicle in an egg cup along with a caption claiming we're all money obsessed man children.
Of course he made his millions in the first dot so he's a bit of a hypocrite...
very timely with the chapter on floppy tracks and heads.
I never read anything so detailed about woz work. Usually it's all average apple fan or journalist reverence. But I really love the way he makes that extra step to use the hardware almost fully.
Woz is really special guy.
> I opened up the little box with a screwdriver, and there were some dip switches, and I switched them to another position, and didn’t get billed for the movie.
But that was still kind of a dick move, Woz.
1) He was so absorbed in the puzzle, it never crossed his mind that someone else might get a bill instead.
2) He would have been horrified that he had caused someone that inconvenience if he found out.
The track-to-track sound he's describing was very pleasant though.
I remember running it and worrying I borked my mom's floppy drives. But thankfully it didn't.
I thought it was on "silicon salad" but I don't see it. Unless its "text train". Maybe it was online from Nibble magazine. https://archive.org/stream/Beagle_Bros-Silicon_Salad#page/n0...
I remember playing around with the delays in that routine to make the head move at different frequencies. With a little bit of playing around you could make the drive play music.
That's basically the same thing you had to do to make the Apple play music anyway -- do a LDA to a certain address with various timings to toggle the 1 bit speaker. Amazingly enough, you could do legible text to speech with it -- https://en.wikipedia.org/wiki/Software_Automatic_Mouth
There are probably better ones but that should get you started and give you search terms.
I don't understand this sentence. Steve Wozniak is saying that he's never been near hardware or software??