Restoring YC's Xerox Alto: how our boot disk was trashed with random data
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Re: Restoring YC's Xerox Alto: how our boot disk was trashed with random data
#2I love these posts. I don't properly understand the majority of what's being done, but a step by step of somebody solving a difficult problem in a space I know nothing about is so fascinating.
Re: Restoring YC's Xerox Alto: how our boot disk was trashed with random data
#3Hah! Nice job on inverting the random number generator. And note that RNGs for testing data patterns have much less stringent requirements than cryptographically secure RNGs :-). I'm hopeful that a known good disk will actually boot something.
Re: Restoring YC's Xerox Alto: how our boot disk was trashed with random data
#4I love these posts. I don't properly understand the majority of what's being done, but a step by step of somebody solving a difficult problem in a space I know nothing about is so fascinating.
This series, assembled and fleshed out, would make a fine book.
Re: Restoring YC's Xerox Alto: how our boot disk was trashed with random data
#5I love these posts. I don't properly understand the majority of what's being done, but a step by step of somebody solving a difficult problem in a space I know nothing about is so fascinating.
I love these posts too, but man is it a pain to read on mobile. Quit hijacking my input!
Edit: I know I can use the readability mode, but I don't like being essentially forced to do so.
Re: Restoring YC's Xerox Alto: how our boot disk was trashed with random data
#6Typo: "7141 TTL chip" should be "7414 TTL chip"
Re: Restoring YC's Xerox Alto: how our boot disk was trashed with random data
#7I love these posts. I don't properly understand the majority of what's being done, but a step by step of somebody solving a difficult problem in a space I know nothing about is so fascinating.
I love these posts too, but man is it a pain to read on mobile. Quit hijacking my input! Edit: I know I can use the readability mode, but I don't like being essentially forced to do so.
Can you explain what the problem is? I recently switched the mobile formatting so Google would stop complaining that my page wasn't optimized for mobile. But maybe that made things worse.
Re: Restoring YC's Xerox Alto: how our boot disk was trashed with random data
#8Typo: "7141 TTL chip" should be "7414 TTL chip"
Fixed. The spell-check didn't catch that for some reason :-)
Re: Restoring YC's Xerox Alto: how our boot disk was trashed with random data
#9I know it's not really relevant to the repair work, but I jumped back to the first article, at http://www.righto.com/2016/06/y-combinators-xerox-alto-resto... . It says
> The biggest impact of the Alto was in 1979 when Steve Jobs famously toured Xerox and saw the Alto and other machines. When Jobs saw the advanced graphics of the Alto and Star, he was inspired to base the user interfaces of the Lisa and Macintosh systems on Xerox's ideas, making the GUI available to the mass market.
The reference is " Malcolm Gladwell describes Steve Jobs' visit to Xerox in detail in Creation Myth."
But quoting http://web.stanford.edu/dept/SUL/sites/mac/parc.html :
> The closest thing in the history of computing to a Prometheus myth is the late 1979 visit to Xerox PARC by a group of Apple engineers and executives led by Steve Jobs. According to early reports, it was on this visit that Jobs discovered the mouse, windows, icons, and other technologies that had been developed at PARC. ... It's a good story. Unfortunately, it's also wrong in almost every way a story can be wrong. ...
> Both the Macintosh and Lisa projects were underway before the 1979 visit. Documents in The Book of Macintosh (a collection of essays, technical specs, and brainstorms written by Jef Raskin on and others) dating from the fall of 1979-- months before the PARC visit-- show that the Macintosh was going to feature user-friendly interfaces; a screen that could handle multiple fonts (that is, bitmapped screens); graphics capabilities; and a graphical input device. ...
> Finally, as several authors have pointed out, there were actually two visits by groups from Apple to Xerox PARC in 1979. Steve Jobs was on the second of the two.
Re: Restoring YC's Xerox Alto: how our boot disk was trashed with random data
#10Hah! Nice job on inverting the random number generator. And note that RNGs for testing data patterns have much less stringent requirements than cryptographically secure RNGs :-). I'm hopeful that a known good disk will actually boot something.
Getting a good RNG on 1970s hardware is almost impossible without some kind of custom device. There is no end to examples of horrible RNGs from that era, sometimes manifesting in amusing ways. There was an implementation of Minesweeper that naively used the rand() call from C's standard library and generated utterly predictable boards.
I am rather impressed at how the author of the article actually tracked down the appropriate RNG function to verify exactly what happened. This is only possible because the PARC community was so small there would only be a couple of ways something like this could have possibly happened?