3 ms·

Here's the text transcript for those who have a hard time reading this blurry document: To: Bob Metcalf and Dave Boggs Date: March 5, 1979 From R.E. Bachrach

Here's the text transcript for those who have a hard time reading this blurry document: To: Bob Metcalf and Dave Boggs Date: March 5, 1979 From R.E. Bachrach Location: PARC - Bldg. 31 Subect: Comments on "Draft Ethernet Overview" Organization: GSL - 44 I have read with dismay your presentation "Draft Ethernet Overview". As I am sure you are aware, technically or conceptually there is nothing new in your proposal. Perhaps appropriately, you have chosen a coined jargon utilizing discredited scientific conceptual expression in which to frame your ideas. I find your analysis on the proposed interconnection lacking in technical credibility. Quantitative statistical analysis would show that your proposed system would be a failure. You have tried to adopt a scheme inappropriate to the intended engineering application. A random transmission scheme such as you propose, along with the quasi-de-randomizing hardware you invoke to patch the obvious deficiency, would place in fact an undo hardware, software, and scheduling problem on the individual stations. You should seriously reconsider your basic premise and formulate fully and logically all the parameters necessary to evaluate the system. Your transmission medium or environment is not quantum noise limited. Simple analysis shows that imposing a poisson (i.e., random) statistics on message transmission drastically reduces the available effective bandwidth. Such a system is effective (reasonable) only in the limit of negligible average bit transmission rates. In fact you will want to maintain as high an effective transmission rate as possible. This requires a synchronized system. The fallacy in your conception is that the stations should be transmitting randomly. One possibility for a synchronized system would be time division multiplexing. You should seriously study how the telephone companies handle this problem. For example, the A.T.T Long lines T2 buried microwave link multiplexes close to 10^7 - 6 KHz channels. Most importantly, you should fully define your engineering application before proceeding further. You specify an undefined message packet length, a 1 mile or 1 mile diameter look and 256 stations working ad 3Mbs rate. What is the nature of the station? How many bits transmitted does an activity require and what is the expected average rate that the 256 stations will be seeking use of the bus in the contemplated application? What is a tolerable dead time for a given station to acquire a full set of data? The worst case delay for your 1 mile loop is 2~ usec. what effect dos this have on far stations getting locked out, etc. . . ? Robert Bachrach

jeffadotio 7y ago
The article seems to miss the concept of criticizing an idea without criticizing the individual. This approach is ineffective as a means of communication. It just looks like mud-slinging and it always comes off as a defense mechanism. Even when one is genuinely interested in addressing the issue this obscures that intent. Edit: Also, thank you for posting the text. I came to the comments hoping this had been done.
- enneff 7y ago
  Sorry, where is the OP critiquing the individual? I can't see it.
- justin66 7y ago
  Seventies-era Xerox PARC cultivated a deliberately confrontational environment for its researchers. They managed to accomplish some great things.
  - kondro 7y ago
    "They managed to accomplish some great things" in spite of being jerks to each other. Imagine what they could've accomplished if they had empathy and were collegial with each other.
    - Gibbon1 7y ago
      When you consider, other people took their ideas and build companies worth hundreds of billions out of them, but they themselves didn't. hmmm...
- fogetti 7y ago
  Where was he criticizing the individual? I can't find it in the text
lisper 7y ago
And here's a follow-up he wrote in 2008: https://www.reddit.com/r/reddit.com/comments/1xz13/in_1974_xerox_parc_engineers_invented_ethernet/c043yl0/ https://www.reddit.com/r/reddit.com/comments/1xz13/in_1974_x... --- Appropriately, through a conversation with Comedian Wayne Cutter (http://www.waynecotter.com http://www.waynecotter.com) about Xerox PARC, I became aware in a Google search that my March 4, 1974 private Xerox Confidential Memo to Bob Metcalf and Dave Boggs was floating around the Internet and a major subject on numerous blogs. Unfortunately the role of my memo in the development of Ethernet II is not understood. Ethernet was the invention of Bob Metcalf and Dave Boggs as an outgrowth of Bob’s PhD thesis on the Aloha Net packet communications network. As is well documented, Xerox PARC from the beginning (1972-1974) was investigating distributed computing and several methods were in various stages of concept and feasibility development. I joined the Xerox PARC General Sciences Laboratory from Bell Laboratories in the summer of 1973 where I had worked on the first commercialization of light emitting diodes. At PARC our group was participating in the founding of the Stanford Synchrotron Radiation Laboratory. The prototype equipment we developed is now in the Smithsonian Museum. Part of this equipment was an advanced computer aided data acquisition system I developed. Although I am a condensed matter physicist, I was very interested in computers and software. I often hung out with the guys in the Computer Science Lab (one of whom recently visited the space station) which is how I received the first draft of Bob Metcalf’s and Dave Bogg’s technical paper describing their networking concept. (The team by the way was somewhat like Jobs and Wozniak in their respective contributions.) Our practice at the time, as it was at Bell Labs, was to have open and frank critique and internal review of technical papers before they were publicly released. It was in that spirit that I wrote my memo which only took on mythical proportions because CSL Lab Manager Bob Taylor chose to post it on his door. CSL at that time was something of a “hippy commune” and meetings were held with everyone lying around on bean bags. The first draft of the Ethernet I paper was written accordingly in a hip style. At the time I considered the draft quite an unprofessional document in addition to my technical concerns. I also at the time did not like the idea of naming a major new networking innovation after a discredited physics concept, the “ether”. The ether doesn’t exist and this was a real network on a real baseband coaxial cable medium. At the time of Ethernet I, packet collision detection was done in software with a CRC check of each packet. Detection of damaged packets would trigger staged random backoff until the valid packet was received. Following the “memo”, Bob Metcalf, Dave Boggs and I got together and had an extensive technical discussion of their paper on Ethernet I and its limitations. In that meeting I introduced them to the collision detection techniques used in pulse counting apparatus such as I used in my photon counting spectroscopic equipment at Bells Labs and at SSRL.1 Basically the receiver detection is an analogue to digital conversion and by suitable discrimination, one can distinguish between on and two pulse events. If two packets collided on the Ethernet cable at the tranceiver, then the receiver could determine that the pulse signal was wrong. The outcome of this discussion was Ethernet II. The Ethernet II hardware collision detection incorporated into the transceiver resulted from this discussion and transformed the networking capability and resolved many of the concerns I raised in my memo. Hardware collision detection enables an Ethernet communication channel to achieve effective utilization while limiting the system overhead and paved the way for Ethernet’s future success as we know it today. So to all the blogger’s out there, I was not a “Xerox Executive”, I was a member of the technical staff contributing to the fertile discussion in a very creative multi-disciplinary lab. I have grown to like the name Ethernet because of what has been accomplished. I don’t even mind all the other subsequent packet communication techniques that call themselves XXX-Ethernet and aren’t. So you should now switch your attention to Liveboard, a PARC invention pioneered by John Seeley Brown. Liveboard in the mid ‘80’s envisioned large flat panel interactive networked computer displays which could be used for group meetings and networked meetings. Through my work at Applied Materials over the last 17 years, we have created the ability to cost effectively manufacture such large LCD flat panel displays. LCD-TV and Computer Displays of 65”, 75”, and 108” are now entering mass production by our customers. Soon they will be in homes, offices, class-rooms and enumerable public spaces. These Liveboard displays will now be connected by Ethernet and also be lit by light emitting diodes whose commercialization I also helped pioneer. Every time you look at your computer display, you are looking at technology I helped to create and enabled it’s volume manufacturing. In case you didn’t know. LCD displays are enabled by amorphous silicon transistors, another technology pioneered at Xerox PARC and commercialized by Applied Materials manufacturing equipment.. R.Z. Bachrach, Memorial Day Weekend, 2008. CAnonymous@earthlink.net R. Z. Bachrach, Rev. Sci. Inst., 43, 734 (1972), "A Photon Counting Apparatus for Kinetic and Spectral Measurements."

jeffadotio 7y ago

The article seems to miss the concept of criticizing an idea without criticizing the individual. This approach is ineffective as a means of communication. It just looks like mud-slinging and it always comes off as a defense mechanism. Even when one is genuinely interested in addressing the issue this obscures that intent. Edit: Also, thank you for posting the text. I came to the comments hoping this had been done.

enneff 7y ago
Sorry, where is the OP critiquing the individual? I can't see it.
justin66 7y ago
Seventies-era Xerox PARC cultivated a deliberately confrontational environment for its researchers. They managed to accomplish some great things.
- kondro 7y ago
  "They managed to accomplish some great things" in spite of being jerks to each other. Imagine what they could've accomplished if they had empathy and were collegial with each other.
  - Gibbon1 7y ago
    When you consider, other people took their ideas and build companies worth hundreds of billions out of them, but they themselves didn't. hmmm...
fogetti 7y ago
Where was he criticizing the individual? I can't find it in the text

lisper 7y ago

And here's a follow-up he wrote in 2008: https://www.reddit.com/r/reddit.com/comments/1xz13/in_1974_xerox_parc_engineers_invented_ethernet/c043yl0/ https://www.reddit.com/r/reddit.com/comments/1xz13/in_1974_x... --- Appropriately, through a conversation with Comedian Wayne Cutter (http://www.waynecotter.com http://www.waynecotter.com) about Xerox PARC, I became aware in a Google search that my March 4, 1974 private Xerox Confidential Memo to Bob Metcalf and Dave Boggs was floating around the Internet and a major subject on numerous blogs. Unfortunately the role of my memo in the development of Ethernet II is not understood. Ethernet was the invention of Bob Metcalf and Dave Boggs as an outgrowth of Bob’s PhD thesis on the Aloha Net packet communications network. As is well documented, Xerox PARC from the beginning (1972-1974) was investigating distributed computing and several methods were in various stages of concept and feasibility development. I joined the Xerox PARC General Sciences Laboratory from Bell Laboratories in the summer of 1973 where I had worked on the first commercialization of light emitting diodes. At PARC our group was participating in the founding of the Stanford Synchrotron Radiation Laboratory. The prototype equipment we developed is now in the Smithsonian Museum. Part of this equipment was an advanced computer aided data acquisition system I developed. Although I am a condensed matter physicist, I was very interested in computers and software. I often hung out with the guys in the Computer Science Lab (one of whom recently visited the space station) which is how I received the first draft of Bob Metcalf’s and Dave Bogg’s technical paper describing their networking concept. (The team by the way was somewhat like Jobs and Wozniak in their respective contributions.) Our practice at the time, as it was at Bell Labs, was to have open and frank critique and internal review of technical papers before they were publicly released. It was in that spirit that I wrote my memo which only took on mythical proportions because CSL Lab Manager Bob Taylor chose to post it on his door. CSL at that time was something of a “hippy commune” and meetings were held with everyone lying around on bean bags. The first draft of the Ethernet I paper was written accordingly in a hip style. At the time I considered the draft quite an unprofessional document in addition to my technical concerns. I also at the time did not like the idea of naming a major new networking innovation after a discredited physics concept, the “ether”. The ether doesn’t exist and this was a real network on a real baseband coaxial cable medium. At the time of Ethernet I, packet collision detection was done in software with a CRC check of each packet. Detection of damaged packets would trigger staged random backoff until the valid packet was received. Following the “memo”, Bob Metcalf, Dave Boggs and I got together and had an extensive technical discussion of their paper on Ethernet I and its limitations. In that meeting I introduced them to the collision detection techniques used in pulse counting apparatus such as I used in my photon counting spectroscopic equipment at Bells Labs and at SSRL.1 Basically the receiver detection is an analogue to digital conversion and by suitable discrimination, one can distinguish between on and two pulse events. If two packets collided on the Ethernet cable at the tranceiver, then the receiver could determine that the pulse signal was wrong. The outcome of this discussion was Ethernet II. The Ethernet II hardware collision detection incorporated into the transceiver resulted from this discussion and transformed the networking capability and resolved many of the concerns I raised in my memo. Hardware collision detection enables an Ethernet communication channel to achieve effective utilization while limiting the system overhead and paved the way for Ethernet’s future success as we know it today. So to all the blogger’s out there, I was not a “Xerox Executive”, I was a member of the technical staff contributing to the fertile discussion in a very creative multi-disciplinary lab. I have grown to like the name Ethernet because of what has been accomplished. I don’t even mind all the other subsequent packet communication techniques that call themselves XXX-Ethernet and aren’t. So you should now switch your attention to Liveboard, a PARC invention pioneered by John Seeley Brown. Liveboard in the mid ‘80’s envisioned large flat panel interactive networked computer displays which could be used for group meetings and networked meetings. Through my work at Applied Materials over the last 17 years, we have created the ability to cost effectively manufacture such large LCD flat panel displays. LCD-TV and Computer Displays of 65”, 75”, and 108” are now entering mass production by our customers. Soon they will be in homes, offices, class-rooms and enumerable public spaces. These Liveboard displays will now be connected by Ethernet and also be lit by light emitting diodes whose commercialization I also helped pioneer. Every time you look at your computer display, you are looking at technology I helped to create and enabled it’s volume manufacturing. In case you didn’t know. LCD displays are enabled by amorphous silicon transistors, another technology pioneered at Xerox PARC and commercialized by Applied Materials manufacturing equipment.. R.Z. Bachrach, Memorial Day Weekend, 2008. CAnonymous@earthlink.net R. Z. Bachrach, Rev. Sci. Inst., 43, 734 (1972), "A Photon Counting Apparatus for Kinetic and Spectral Measurements."