Timberwoof Essays Xerox Star
The Last Demo
of the Xerox Star

In June of 1998 some people at the Xerox Palo Alto Research Center (Xerox PARC) resurrected and got operational a pair of Xerox Star minicomputers and held a talk called "The Last Demo of the Xerox Star." I had the good fortune to read about it on a newsgroup and take time off from work to go. I recently found my notes from that lecture and present them here.

Notes from "The Last Demo of the Xerox Star"

Xerox Star — "Last Demo"
PARC 1970-1975
Xerox - "Architect of Infromation"
1973 - Alto & Ethernet. Pad-sized computer prototype.
1975 Jan "You can't extrapolate backwards and get there."
There have been discontinuities.

Interactive - Dumb terminals; "Intelligent" terminals.
Word processing - from IBM Deutschland; electromechanical.
IBM - biggest player.
Xerox - biggest threat. Diablo printer.
Software from mainframe vendors or custom for customer.
Turnkey office systems.
No personal computers yet.
Xerox had bought Scientific Data Systems.
Sigma Scientific -> Business.
1975 Xerox sold SDS to Honeywell.
But Xerox had computer experts.

Xerox had antitrust lawsuit over copiers; owned Shugart (Seagate); big fast laser printers.

10 year system architecture for electronic copying & printing for professionals.
long term for paperless office.

1975 OIS Architecture (Shipped by 1981)
• PSN -> ethernet
• client/server
• scalable CPU instruction set - implementation independent
• OS Baroque to Rococo then. VM 512kB!
• development environment
• routers, bridges
• Star 8010

Do more than just memos. More than a typewriter.
Equation typesetting would sell laser printers.
Expand Xerox brand name to peoples' desks.

1978 - personal interactive software was unknown.
1988 - Mac caught up. OS 6
1993 - Windows caught up. W3.1

1972 Alto: email, FTP, office automation, CAD. } redo it all from scratch.

7481 CPU
16 bit 600 x 800 pixel display [tall]
512kB RAM
removable HD
170ns - 6MHz CPU
32bit - 32Mbit/sec bandwidth
CPU did disk I/O, 16 byte buffer.

1024 x 800
54 Mbits/sec memory
10mbit ethernet
10mbit disk

4 2901 CPUs National Semiconductor
1 ns instructions
300 ns memory

clock cycles were allocated to hardware i/o devices & instructions - like CPU bus in modern machine.

8085 for llow speed I/O: leybolard, mouse, disk, clock

needed cluster processor: dandelion code name
(dandelion is a wildflower but lion is a beast)

last bipolar CPU
1981 -> CMOS

1981 Mac development started

Goal: picture on screen by Christmas 1979
accomplished by hooking scanner to memory

Machine architecture is based on financial & cultural influences on designers.
Huge: PDP/10 36 bits 2Mips 1Mword memory
too big: PDP11/60 16bit 1/2Mips 1/4MB memory

Star - office appliance, fixed function
- No GP I/O bus -> tiny I/O hardware
expand via ethernet
1/3 of power, weight, cost.

memory - 5 rounds allocated to HW
a device could access memory
guaranteed not to lose data

"Correct by construction"

7 MHz clock speed bit-sliced 4 parts 1/4 MB 8MB VM

3 Mbit ethernet only 88 chips 12" x 8" board

20 Mbit did not fit.
10 Mbit chip from Fairchild made it work.
That is why Ethernet is 10 Mbit/sec.

Disk ran synchronized with CPU
didn't work in Japan - 50Hz

1000x memory in disks and RAM - Physical
"So the software had better be a thousand times better."

38fps 800x1024; 32 lines border pattern
Could not use black border pattern to not imply [that] people were dead.

Video ran synchronously with CPU, too.

8085 ran 8" floppy drive

keyboard controller, com ports, etc.

then: 800kB floppy
now: 100MB Zip

email, networked design environment allowed 24-hour design —
team communications.

Moore's Law since 1959: CPU, RAM 1000x since the Star;
I/O has only increased 10x

Dave Smith - Human Factors engineer.
8010; 6085 v2.

"It's hard to give a demo on Star. People anymore say "What's the big deal?"

• bring computer to professionals, not professionals to computer.

World was character driven; command line.

1st visual point & click
1st object-oriented
1st icons
1st UI standards
1st ethernet laser printer

but it tried to do too much.
but it was closed <- biggest mistake.
Mac toolbox was a huge improvement.

2 button mouse -
1 was too few; 3 were unnecessary.
"Mac has 2 buttons. The second one is on the keyboard."

Biggest reason for success was keyboard-
[Delete], [Copy], [Move], [Show Properties]
most important functions were keys on the left side

Font effects across the top: bold, italic, underline, …

very few commands to do complicated things
Demo uses only a dozen commands.

Powerful ideas - Pervasiveness
Copying - easter than creating from sratch. Multiple choice rather than fill in the blank.
Command line forces you to generate a command (menu lets you choose a command)
Star [was] networked from the start.

White bar at top is area for messages.
"Open" key.
Network directory icon-
Winow lists categories
basic document: copy, then deposit on desktop.

Icons looked like docs, folders, file cabinets, waste basket.


Not until Mosaic was there a similar interface.

New doc - copy a blank document and edit it.

Objects have state and behavior.
Show properties shows state.
WP commands: ? Close Layout
Properties window - ¶ character
[Show Properties] key.

Remap with context.
keyboard key - top of window shows meanings of keys.
Like "Keycaps" but shows more meanings of special-function keys.
Within graphics frame, top row of keys become graphics keys. Electronic transfer paper copy a thing to graphics frame.

Copy bargraph, drag to resize
show properties - includes data table.

Equation frame remaps keyboard to equation symbols
[Sigma] for instance, fills in the parameters one by one with the [Next] key.

Greek keyboard.

Mathematically typeset correct equation only using keyboard and smart equation object.

To print or email, drag to printer.

Data icons - folders, cabinets, files
Function icons - mailboxes, Printers, File cabinets - "Move" command.

17 years, 1000x later.

"Star's interface is still simpler, more consistent, more useful than today."

Fewer commands, not not fewer functions.

Copy paradigm.
Generic function keys.
Objects with properties.
Smart objects with inspectors.
Simple icons.

Other technologies developed at Xerox:

1st release had more than ascii
Japanese, 6 months later. 1983.
... this became Unicode.

Directory services.
Remote procedure calls.
Print protocol.
CUSP - customer programming (consultants programmed)
Boot servers --> app servers, Java
Remote access.

In August, 1998 I wrote…

I was at the "last" demonstration of the Xerox Star at PARC a few weeks ago. It is an interesting computer, and was fairly advanced for its time. I liked the way it did some things, and I wish the Mac (and thus Windows) had done them the same way. But the Mac is not a clone of the Star, it is a significant development on top of the Star's basic concepts. Windows is much more similar to the Mac than the Mac is to the Star.


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