Woz’s take on the Apple 1’s noisy -5 volt supply

[jaysonelliot]

My favorite quote from Woz's reply is this:

"I awoke one night in Quito, Ecuador, this year and came up with a way to save a chip or two from the Apple II, and a trivial way to have the 2 grays of the Apple II be different (light gray and dark gray) but it’s 38 years too late."

This is how you know you love your work. When you're still thinking of new things you can optimize, even four decades later.

[jgrahamc]

I would buy Woz's improved Apple ][ if he started selling them.

[melling]

Why is that cool? There's no doubt that Woz brilliant. However, I wish he had a second act. That he would come out with some sort of cool wearable or something else.

Steve Jobs kept trying to invent the next big thing. Apple II, Macintosh, NeXT, iPod, iPhone. For some reason, engineers often don't think like this

[rbanffy]

Indeed.

If he describes the two grays thing in more detail, someone could implement it in MESS at least.

Woz: are you reading this?

[EvanAnderson]

I'm consistently impressed by the sincerity and humility that comes through in what Woz says and writes. Not only is he a great engineer, but he just seems like a really great guy.

[LeonM]

Woz sure seems like a humble guy.

You should read his biography 'iWoz' [0], it's a really nice read.

[0] http://www.amazon.com/iWoz-Computer-Invented-Personal-Co-Fou...

[alexose]

)

Don't worry-- I closed the unclosed parenthesis.

[BigTuna]

When you read responses like this it's impossible not to be in awe of the guy. He's a great role model for newer generations both in his passion for his work and his top-notch personality.

[Danieru]

I want to hear how he'd do the gray thing, it sounds interesting.

[Siecje]

There is a comment on the page that touches on it.

[nagarjun]

Fantastic to see how humble he is with his response. He could have easily said "that's how it was done back then and it was really the best thing out there" but, he didn't. The stuff of legend.

[boxcardavin]

Woz is such a cool guy, he reminds a lot of startup guys of how much pure fun tech was when you were 8-15yrs old and not thinking about money.

[jamesaguilar]

Hi, I've been trying to figure this out for a while, and it's a hell of a thing to get Google to understand. Can someone explain why the rail is referred to as "-5v" instead of its opposite simply being called "5v"?

[pjc50]

Because it's 5V below the "ground"/0V rail which most things are referenced to. It's very inconvenient to keep referring to the 17V rail and the 10V rail above the 5V return rail, so you call those 12V, 5V and 0V. The majority return current is in the 0V rail. The -5V rail supplies (conventional) current which also returns to the 0V rail.

(In fact there is usually very little current in the -5V rail, just leakage through transistors; it's used as a bias voltage for the DRAM substrate. http://books.google.co.uk/books?id=TgW3LTubREQC&pg=PA158&lpg... )

[rrmm]

The power supply output 12, 5, -5, -12 volts. -5v rail was for the DRAM.

[raverbashing]

Yes, there's always something to optimize, but also shipping is needed.

I'm not sure what the -5v was used on, but apparently it wasn't a huge issue.

It doesn't matter anymore. It matters what you can learn with it.

[cnvogel]

It's the DRAM.

Mostek MK4027 (1 Chip, 4096x1 bits each), needs +5V, -5V and +12V.

https://www.google.de/search?q=Mostek+MK4027

[RankingMember]

There's a guy who genuinely lives/breathes electronics.