Analysis of papers written by Donald W. Davies on “Packet Switching & Communication Networks”

Prepared by: “Three Lyricist” (IEEE CHC61 Team, Team id: 7288P5 ) Date: June 24 2007 Remote on­line data processing and its communication needs – Nov. 10, 1965 [ Davies02.pdf ]

ANALYSIS:

This note described a “store and forward” system for short messages. Donald Davies was aware of the security issues associated with on­line data processing. He wrote, “the security of the information is a problem, however, which leads to a subject of research:Security of data in doing business via a national network. (This refers to security against unauthorized access rather than against loss of data.)” in this note (ref. [1], Para. 6, Pg. 1). It predicted that such a ‘short­message’ data service would take over the telegraph and telex services and make them more convenient because the other applications would cover the cost of many more sets of terminal equipment. He further adds in this note, “The interaction with the system might have to be simplified so that anyone used to the keyboard could send messages as well as operate his own specialized services.”. This suggests that he had proposed a system which could also provide messaging services similar to present day email.

Further speculations on data transmission – Nov. 16, 1965 [ Davies03.pdf ]

ANALYSIS:

This note appeared as a short supplementary note to Nov. 10, 1965 (ref. [1]) note which among other things listed 12 special facilities which a new network could provide. In his email (ref. [3]) to Prof. Chris Edmondson Yurkanan Davies wrote, “This note looked at some human factors issues and seems now to be a description of today's e­mail interfaces.”. Davies had proposed an interface similar to present day email service (Massachusetts engineer named Ray Tomlinson sent first electronic mail in late 1971).

References: [1] D W Davies. Remote on­line data processing and its communication needs, Nov. 10, 1965 [2] D W Davies. Further speculations on data transmission, Nov. 16 1965 [3] D W Davies. Letter to Chris Edmondson Yurkanan, Aug. 25 1999 [ http://www.cs.utexas.edu/users/chris/DIGITAL_ARCHIVE/NPL/DaviesLetter.html ] Proposal for the development of a national communication service for on­line data processing ­ 15 December 1965 [ Davies04.pdf ]

ANALYSIS:

Prof. Chris Edmondson­Yurkanan (ref. [3], Pg. 65) writes Davies forecast today’s “killer app” for his new communication service: “The greatest traffic could only come if the public used this means for everyday purposes such as shopping... People sending inquiries and placing orders for goods of all kinds will make up a large section of the traffic... Business use of the telephone may be reduced by the growth of the kind of service we contemplate.”

Some of the usage of the proposed “Message Communication Network” as forecast by Davies (ref. [1] Para. 1, Pg. 9) are:

• Numerical computation at various levels of generality try Google search with this keyword “2^1000”. Google built­in calculator can solve math problems involving basic arithmetic, more complicated math, units of measure and conversions, and physical constants. [ http://www.google.com.np/intl/en/help/features.html#calculator ] • Editing and typesetting of text Google Docs & Spreadsheets allows you to create, edit and publish documents and spreadsheets. [ http://docs.google.com ] • Design services and problem oriented languages • Availability of goods for sale • Ordering of goods • Invoicing, delivery notes, etc. • Booking of transport • Banking, establishing credit • Remote access to national records, e.g. MPNI, tax, police, medical, on a secure basis • Betting

We don't think we have to give the present day Internet services that correspond to some of the items in the above list. If you ask somebody to note down the things we can do on Internet, I am sure that a list similar to above would come out.

The Internet services we take for granted, was predicted by Davies in Dec. 1965. He had a true vision of present day Internet and had the technical capability to build the proposed “Message Communication Network”. He circulated this proposal widely among those who he knew were interested such as Banks and the UK Post Office. The reaction was generally appreciative but not enthusiastic. Unfortunately, Davies’ design received minimal funding. References: [1] D W Davies. Proposal for the Development of a National Communication Service for on­line Data Processing, Dec. 15 1965 [2] D W Davies. Letter to Chris Edmondson Yurkanan, Aug. 25 1999 [ http://www.cs.utexas.edu/users/chris/DIGITAL_ARCHIVE/NPL/DaviesLetter.html ] [3] Chris Edmondson Yurkanan. SIGCOMM's archaeological journey into networking's past. COMMUNICATIONS OF THE ACM May 2007/Vol. 50, No. 5 [ http://doi.acm.org/10.1145/1230819.1230840 ] Proposal for a Digital Communication Network – June 1966 [ Davies05.pdf ]

ANALYSIS:

The term “packet“ appears for the first time, in print, in this paper. In his historical note (ref. [1], Para. 3, Pg. 4) Davies wrote, ”This document is the first one which uses the word ‘packet’, a word which I introduced to make a distinction between the message unit which the network employed and the message which the user wanted to send”. In March 1966 Davies gave a lecture at the NPL entitled ‘The future digital communication network’. This was attended by more than 100 people of whom 18 were from the UK Post Office. After the lecture, Dr. A. Llewellyn (a man from the British Ministry of Defense) offered to send him the report by Baran Boehm and Smith of the work at Rand Corporation which, though it had been published by Paul Baran in 1964, had yet not come to his attention. By coincidence they had independently chosen 1.5 Mbit/s and 1024 bits as their main parameters. This meant that both of them (Paul Baran and Donald W. Davies) had come up, independently, with similar idea of packet switching. Hence Donald W. Davies is known as a co­inventor of the packet switched network paradigm. The contents of this lecture was later recorded and circulated privately entitled ‘Proposal for a digital communication network’ dated June 1966 (ref. [2]). This paper contained extensive details of the proposed communication network along with the “cost estimate” to implement such system. The first line of this paper (ref. [2], Para. 1, Pg. 1) read, “In this report an outline case is made for the development of a new kind of national communication network which would complement the existing telephone and telegraph networks”. In the UK there were some political dangers in entering the field of communication because the provision of telecommunication services was a monopoly of the Post Office. Davies' combination of professional expertise and political awareness successfully avoided this pitfall. In his historical note (ref. [1], Para. 3, Pg. 4) Davies wrote,” The Post Office reaction at the March 1966 lecture and at discussions which followed was surprisingly tolerant towards this proposal. People in my own Department, the Ministry of Technology as it was then called, were also interested but it was never considered seriously as a practical possibility”.

References: [1] D W Davies. Historical Note on the Early Development of Packet Switching [ http://www.cs.utexas.edu/users/chris/DIGITAL_ARCHIVE/NPL/Davies01.pdf ] [2] D W Davies. Proposal for a Digital Communication Network, June 1966 A DIGITAL COMMUNICATION NETWORK FOR COMPUTERS GIVING RAPID RESPONSE AT REMOTE TERMINALS – Oct. 1967 [ Davies06.pdf ]

Analysis:

A Data Communication group was established in Autonomics Division at NPL in 1966 led by Derek Barber. Other key members were: ● R. A. Scantlebury ● K. A. Bartlett ● P. T. Wilkinson

Initially the work concentrated on these topics (ref. [3] Para. 1, Pg. 128) : 1. the development of Davies' novel ideas for the technology of computer networks 2. the design and construction of a local packet switched network on the NPL site to put these ideas to practical test.

Davies wrote in his historical note (ref. [1], Para. 5, Pg. 4), “When I became Superintendent of the Division in August 1966 I was able to initiate a programme of research. We decided on a local network in order to test out our ideas for an interface computer ...”. This group (Davies, Scantlebury, Bartlett, Wilkinson) presented a paper at ACM Symposium on Operating System Principles Oct. 1967 Gatlinburg, Tennessee (ref. [2]). This was the first public presentation of NPL work. Davies wrote in his historical note (ref. [1], Para. 6, Pg. 4), “This was an important meeting, attended by many people who subsequently became engaged in packet switching. The paper described the network proposal and recalculated the per packet cost as 0.1 penny for the high level network which is much closer to present day tariffs.”

The first practical networks using packet­switching were the ARPANET and the NPL local network. The ARPANET evolved into the Internet, and the packet switching technique forms the undisputed basis of the worldwide computer communication systems in use today.

References: [1] D W Davies. Historical Note on the Early Development of Packet Switching [ http://www.cs.utexas.edu/users/chris/DIGITAL_ARCHIVE/NPL/Davies01.pdf ] [2] D W Davies, K. A. Bartlett, R. A. Scantlebury, P. T. Wilkinson. A DIGITAL COMMUNICATION NETWORK FOR COMPUTERS GIVING RAPID RESPONSE AT REMOTE TERMINALS. Symposium on Operating System Principles, Oct. 1967 [3] David M Yates. Turing's Legacy. A history of computing at the National Physical Labratory 1945­1995. ISBN: 0 901805 94 7. Science Museum London, 1997