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Celebrating The Origins of Packet Switching

XaN-ASMoDi writes with an interesting historical piece at the BBC on the early history of packet switching, excerpting: "It has often been said that change is the only constant in the 21st Century. And there is little doubt that the restless tone of these times is something that the web has helped to accelerate, but the only reason that [...] the web can cope with that punishing pace is thanks to work done four decades ago by British mathematician Donald Davies at the UK's National Physical Laboratory (NPL). On 5 August 1968 Dr Davies gave the first public presentation of work he had been doing on a method of moving data around computer networks called 'packet switching.'"

8 of 59 comments (clear)

  1. Changing change by Atmchicago · · Score: 4, Interesting

    It's an oddly-specific use of the phrase: does that imply that change has not been constant in other times?

    Re-read it. It says that the only thing that doesn't change in the 21st century is that things change. Arguably, things always change, in which case the phrase is vapid. At the same time, the rate at which things change is accelerating. Compare life in Europe, circa 1000 with 1100. Then compare life in Europe 1900 and 2000 - the differences are much greater!

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  2. Sounds Like Another How I Won the War Story by jmcharry · · Score: 3, Interesting

    A lot of people made contributions around that time. As a then undergraduate flunky in a physics lab, I remember playing with an early network that linked the Illiac II with a bunch of other computers. Since we weren't supposed to be playing with it, all we could do was come up with the login prompts, but several Midwestern universities were linked already. ARPANET sputtered to life in 1969, too soon for the touted theoretical contributions to be seminal. I don't doubt Davies did important work, but the article is over hyped.

  3. Packet switching at NPL by Anonymous Coward · · Score: 2, Interesting

    My Dad worked with Donald Davies. That's him on the far right in the pic on the BBC. He would have been 85 tomorrow.

  4. Where Wizards Stay Up Late by beatbox32 · · Score: 3, Interesting

    Interesting that this event just came up. I just finished reading Where Wizards Stay Up Late: The Origins of the Internet today. For those interested in the history of ARPA and internetworking development (and the people behind these developments - Davies, Kleinrock, Licklider, et. al.), I highly recommend this book.

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  5. Re:Packet switching was originally developed... by Anonymous Coward · · Score: 1, Interesting

    And what about Louis Pouzin ?

    http://en.wikipedia.org/wiki/Louis_Pouzin

    Really I think it was an idea floating during the 60s that a lot of people have been exposed to.

  6. Telegraph and Mail by Comatose51 · · Score: 4, Interesting

    If you want to talk about easy digital, packet based networking, then the telegraph is worth a mention. Messages for electronic telegraphs were sent as packets that are later relayed to its final destination. It was also digital in the sense that each character was transmitted as discrete values. Another predecessor to TCP/IP based networking would be the mail system. While it wasn't digital, it was also packet based and as anyone who've used the postal system knows, it's only best effort. For added cost, you can get ack-like behavior with return receipt.

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  7. Autodin by Sqreater · · Score: 2, Interesting

    I was a Telecommunications Specialist in the military Autodin System (Automatic Digital Network) in the DCS from 1975 until 1979. I was a network troubleshooter - fault isolation and correction. This was a worldwide packet switching system for military communications and supported the NSA need to funnel intercept data back to the US from Menwith Hill and other bases. I could be wrong, but something seems wrong with the given timeline as there was a full-blown worldwide system in 1975 when I entered the service. I had approximately 150 circuits to bases that I was responsible for keeping up - modems, crypto gear, tropospheric scatter and microwave links carried our data (had HF radio too). Was there enough time to set that up? Was there a parallel development that is not showing up in technical history? Just a thought. We used a Philco-Ford, then Aeroneutronics Ford computer for routing. We had two Procs that swapped on error, and drum memory. I viewed the circuits by dialing them up on an "MTC" Monitor and Test Console, to watch the bit traffice on a dual trace oscilliscope. Things have changed so dramatically that I can go onto Google Earth to view my old base and note the changes that have taken place in the interim. I thought the advent of advanced technology would have caused my small base to shut, but that's not the case. It has been security hardened and 4 new large satellite dishes added.

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    1. Re:Autodin by idontgno · · Score: 2, Interesting

      Not to nit-pick, but AUTODIN was message-switched. (I worked AUTODIN software in the early '80s.)

      The distinction between message-switching and packet-switching is small but crucial. The quantum of messaging in a message-switched network is an entire message. That's why AUTODIN implemented overrides and interrupts, permitting a high-precedence message to override a long lower-precedence message. When that happened, the receiving switch discarded the partly-received lower-precedence message, received and processed the higher-precedence message in its entirety, and then began from octet 0 with the next message on the circuit addressed to it (which may be the message it partially received earlier--but with no persistence, it started from the beginning.)

      A packet-switched equivalent would hold the incomplete partial message in core (or disk, I suppose) and receive the packets of the higher-precedence message, assemble that message and process that message, and then continue processing the delayed (not interrupted) remainder of the lower-precedence message.

      Packet switching was, in its time, radical. It allowed organic solutions to problems like precedence-based circuit management in less wasteful ways than message switching. It was also sufficiently different from message-switching in behavior that the software for packet-switching had to be written pretty much from scratch, or bought from a vendor if you were lucky.

      That's the voice of experience speaking: our team wrote a very primitive TCP/IP stack for our Unisys 1100 mainframe, and never shook all the bugs out of it (mostly timing bugs, since realtime interrupt handling on the comm circuits were always a nightmare of race conditions.) We were never so glad when Unisys started offering off-the-shelf LAN hardware and TCP/IP software for those machines, and we could stop wrestling with our own ugly Frankenstein monster.

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