"Two research labs known for some of the tech industry’s most important innovations have merged in hopes of recapturing their glory days." -- #JohnMarkoff

The New York Times · Mar 27, 2024Can Xerox’s PARC, a Silicon Valley Icon, Find New Life with SRI?By John Markoff

#WWW #XeroxParc #SRI

**J❀y** @lurkjay@mastodon.social · Mar 19, 2024

Mar 19, 2024

J❀y @lurkjay@mastodon.social

Dealers of Lightning: Xerox PARC and the Dawn of the Computer Age by Michael A. Hiltzik (1999)

Text instead of screenshots: https://cohost.org/lurkjay/post/5166294-dealers-of-lightning

Thacker reasoned that if each of the computer’s routine tasks could somehow be ranked by urgency and funneled through the processor in appropriate order, he could keep the processor occupied almost full-time. If the ranking was correct, every task would be handled when it needed to be, no sooner and no later. Low-priority tasks could be interrupted for brief periods to make way for more urgent ones, then resumed later, when nothing more pressing was in the way. The gain in efficiency, speed, and hardware was potentially huge. Whole circuit boards that served as the ancillary brains of disk drives and other units could be dispensed with. The Alto’s CPU would be drafted into doing the thinking for all of them.

Thacker’s second crucial inspiration involved the question of how to power a high-performance display without busting the budget on memory. This was not trivial: He understood that the quality of the display would make or break his new computer.

Up until then, computer designers wishing to provide an interactive display faced two equally unappetizing choices: They could give the display little memory support, which led to flickering and slow performance, or they could provide backup memory through a character generator, which meant burdening the system with another and bug-prone peripheral the size of a washing machine.

Thacker struggled at length with the riddle of how to direct a suitable volume of information to the screen without adding excess hardware. The answer came to him one day while he was watching a demonstration of one of Kay’s graphics programs in the Systems Science Lab.

The demo utilized a character generator designed by a former Engelbart engineer named Roger Bates (with Lampson’s assistance). This unit, which had thousands of dollars’ worth of memory inside, was a distant relative of the one Ron Rider would later build for the SLOT. It was designed to store custom fonts by allowing each character to occupy a small rectangular patch of memory until summoned to the screen. Most of the PARC engineers considered it a disappointment, largely because the designers’ ambition to reproduce book-quality pages on the POLOS screen turned out to be a tougher programming challenge than they anticipated.

Kay’s group was an exception. Bored with the idea of painting text on the screen but fascinated with the possibility of displaying images, they had appropriated the system—“perverted it,” in Lampson’s unpejorative phrase—to use for their graphics and animation programs by loading its memory not with print characters, but graphical designs.

The result was a rudimentary black-and-white “bitmap”—a block of memory in which each bit corresponded to a dot on a display screen. Flip a given memory bit “on” and the corresponding dot lit up on the display; turn on these bits in a given pattern and you could map the same image to the screen.

As Lampson explained, “In the normal deal there would be a little bitmap for the character ‘A’ in the font memory and a bitmap for ‘B’ and ‘C’ and so on, and then the character memory would say display an ‘A,’ an ‘h,’ and an ‘a,’ and aha, you have ‘Aha.’ Alan said, ‘We’ll have a whole bunch of artificial characters numbered 1 through 500, and the character memory will say display 1, then 2, then 3.’ The result was to take the font memory and turn it into a bitmap”—that is, well before the lab had the resources to build a full-scale bitmap.

Kay’s group had only begun to investigate the potential of this new way of displaying information (although they had done enough to help persuade Thacker and Lampson of the need to equip the Alto with a high-resolution display). Among their first simple programs was one that could embed “icons,” or thumbnail-sized pictures, within blocks of text. Another was a painting system in which users wielded square “brushes” up to four pixels wide to draw or erase lines and curves on the screen.

Impressed as he was by these applications, Thacker was struck more by the underlying principle by which Kay’s system used the memory blocks.

He realized that just as Kay’s team had turned the character generator into a simple bitmap, he could convert idle blocks of the Alto’s main memory into a bitmap for the display screen. Forcing the memory to perform this double duty would eliminate the need for a separate character generator. This required cutting a few corners, because the display would now have to compete with all of the machine’s other functions for memory blocks. When the Alto placed a text document on its screen, for example, it would economize by omitting from the bitmap any part of the page that lacked text, such as the white spaces between lines and at all four margins. Also, whenever there were competing demands for memory from data and display, the display lost. Users had to be alerted to expect a strange phenomenon: During a work session the image of the document they were writing or editing would gradually shrink, like a window shade rolling up from the bottom. The reason was that as the increasing volume and complexity of the data claimed more memory, less remained for the bitmap. The same phenomenon accounted for what happened whenever the Alto displayed a full-screen graphical image. On those occasions it tended to run agonizingly slowly, in part because so many processor cycles were consumed in painting the screen, but also because the display consumed so much memory there was barely enough left to keep the program percolating along.

#reading #nonfiction #books

**Joachim Tuchel** @Jtuchel@mastodon.social · Mar 14, 2024

Mar 14, 2024

Joachim Tuchel @Jtuchel@mastodon.social

https://spectrum.ieee.org/smalltalk

#smalltalk
#stevejobs #apple #computerhistory #xeroxparc

IEEE Spectrum · Mar 1, 2023Smalltalk Blew Steve Jobs’s MindBy David C. Brock

**Mike Amundsen** @mamund@mastodon.social · Feb 20, 2024

Feb 20, 2024

Mike Amundsen @mamund@mastodon.social

“The destiny of computers is to become interactive intellectual amplifiers for everyone in the world pervasively networked worldwide”.

https://www.quora.com/What-made-Xerox-PARC-special-Who-else-today-is-like-them/answer/Alan-Kay-11

QuoraWhat made Xerox PARC special? Who else today is like them?Alan Kay's answer: A good book (pretty much the only good book) to read about the research community that Parc was a part of is “The Dream Machine” by Mitchell Waldrop. There you will find out about the ARPA (before the “D”) IPTO (Information Processing Techniques Office) set up in 1962 by the vi...

#AlanKay #jcrLicklider #darpa

**Joachim Wiberg** @troglobit · Jan 23, 2024

Jan 23, 2024

Joachim Wiberg @troglobit

Today’s find, from under my bed, from I-don’t-know-how-many-thousand years ago, while looking for my new cat #papers #xeroxparc

Butler W. Lampson’s legendary paper titled Hints for Computer System Design

Replied in thread

**Amin Girasol** @fluidlogic@oldbytes.space · Dec 15, 2023

Dec 15, 2023

Amin Girasol @fluidlogic@oldbytes.space

@jaruzel @StefanoGaivota interesting! To me, #retrocomputing covers early #eightbit (and #sixteenbit) personal computers, and #vintagecomputing covers #mainframe, #minicomputer and #workstation machines (the latter category being composed of #LispMachines, graphical #unix workstations and of course the #XeroxParc machines).

**Dave Mackey** @davidshq@hachyderm.io · Dec 8, 2023 *

Dec 8, 2023 *

Dave Mackey @davidshq@hachyderm.io

thinking about the magic ingredients that foster #tech #innovation. #XeroxPARC, #BellLabs, and #MIT's #TMRC appear frequently in the annals of #history - at least those I've read.

The #question is - how do we create such centers of innovation?

I'm still putting it together but I suspect there are at least four:

1 Time- Insane and copious amounts of it
2 Community- Multiple individuals who interact syngeristically
3 Space- A shared space for innovation to occur
4 Equipment- Raw materials

1/5

**blake shaw** @rml@functional.cafe · Oct 1, 2023 *

Oct 1, 2023 *

blake shaw @rml@functional.cafe

The decisive influence of women on the development of #LispMachine processors and #Scheme in general is criminally under-discussed:

"We had heard that Lynn Conway from Xerox and Carver Mead from Caltech were making real progress on making it possible for people who were not at a chip-fab facility to specify chips for experimental designs. In the Spring of '78 we invited Lynn Conway to teach the class on #VLSI design that she was working on with Carver Mead. Just a few years earlier Guy L. Steele Jr., (then my graduate student) and I invented a simplified but elegant version of the #LISP family of languages that we called Scheme. Guy and I wrote a number of internal memos (Lambda the Ultimate...) that later became famous. Guy enrolled in Lynn's class. For his term project he designed and fabricated a direct interpreter for Scheme, called Scheme-78. It didn't quite work (because of three missing wires); it didn't have a garbage collector; and it was too small to do anything impressive; but it encouraged us to try again. Over the next few months Guy Steele, Jack Holloway, and I designed a new interpreter that we thought could actually be run on a real memory and tested with real programs. I designed the register array, Guy and I developed the microcode. Jack made a PLA generator that could hold the microcode, and we roped Alan Bell of #XeroxPARC into assembling the Scheme-79 Chip. We pulled this off in a few man-months of time and it worked! Scheme-79 had a mark-sweep #GarbageCollector with a Deutsch-Schorr-Waite mark algorithm and a two-finger compacting sweep. It also had a two-level microcode: The main PLA contained rather high-level microcode instructions that were further elaborated by a nanocode PLA that operated the register array.

Further encouraged, I started a new project to make a chip that was actually big enough and fast enough to be useful to run real research programs. This was the Scheme-81 chip. It was a 32-bit machine, with 6 bits of type code and 26 bits of address. It had microcode support for everything required to make a Scheme computer operating system, including a stop-and-copy garbage collector, a coprocessor bus, and an interrupt system. For Scheme-81 the microcode was written by Richard Stallman, Chris Hanson, and me. (Steele had graduated and moved on to CMU as faculty.)"
- Sussman

#WomenInTech #TransPride #lgbt

https://www.artsy.net/article/ruse-laboratories-gerald-jay-sussman-creator-of-scheme

Artsy · Mar 18, 2015Gerald Sussman | ArtsyBiography An eminent academic and influential author, Sussman is one of the world’s most prominent figures in the realm of computer science. A profess...

**Yaroslav Khnygin** @surabax@mastodon.ie · Aug 12, 2023 *

Aug 12, 2023 *

Yaroslav Khnygin @surabax@mastodon.ie

A great paper from 2004 by Richard P. Gabriel (Lucid, Inc.), Jon L White (ditto), Daniel G. Bobrow (Xerox PARC) that explains how Common Lisp Object System integrates functional and object-oriented programming: https://dreamsongs.com/Files/clos-cacm.pdf

#Lisp #CommonLisp #CLOS

**chX0Rsec🖳** @chxsec@infosec.exchange · Jul 30, 2023

Jul 30, 2023

chX0Rsec🖳 @chxsec@infosec.exchange

https://youtu.be/pQocN_c2uLI
The Xerox Thieves, Steve Jobs and Bill Gates. #Xerox #XeroxPARC #GUI

YouTubeThe Xerox Thieves: Steve Jobs & Bill GatesBy Business Casual

**Blake Patterson** @blakespot@oldbytes.space · Jul 27, 2023

Jul 27, 2023

Blake Patterson @blakespot@oldbytes.space

All about Xerox PARC from The Chip Letter.

PARC is one of the richest slices of computing history. And the mentioned Hiltzik book is one of the best computing history books I've read.

https://thechipletter.substack.com/p/chip-letter-links-no-21-xerox-parc

The Chip LetterChip Letter Links No. 21 : Xerox PARC SpecialBy Babbage

#XEROX #PARC #XEROXPARC

**Hank G** @hankg@friendica.myportal.social · Jul 26, 2023

Jul 26, 2023

Hank G @hankg@friendica.myportal.social

A bunch of old videos from Xerox PARC just got dumped on the Computer History Museum's YouTube channel. This is just one of them. Really neat stuff. #RetroComputing #XeroxPARC youtu.be/rR_24-_83-o

YouTubeDraw DemoBy Computer History Museum

Continued thread

**Aslak Raanes** @aslakr@mastodon.social · Jul 19, 2023 *

Jul 19, 2023 *

Aslak Raanes @aslakr@mastodon.social

I intervjuet forsøker Kristen Nygård å forklare objektorientert programmering (#OOP).

I tillegg til Ole-Johan Dahl så nevnes Alan Kay, Xerox PARC, #SmallTalk og Apple Lisa (skrevet som LISA). Endel unøyaktigheter er det i teksten, f.eks. Alan Kay skrev ikke SmallTalk alene, men det er vel ikke så galt til å være et reklameblad.