{"id":2265,"date":"2010-08-17T12:20:54","date_gmt":"2010-08-17T12:20:54","guid":{"rendered":"http:\/\/meeseeks:5080\/blog\/?p=2265"},"modified":"2022-01-18T16:12:49","modified_gmt":"2022-01-18T16:12:49","slug":"the-long-after-life-of-design-decisions","status":"publish","type":"post","link":"https:\/\/vukutu.com\/blog\/2010\/08\/the-long-after-life-of-design-decisions\/","title":{"rendered":"The long after-life of design decisions"},"content":{"rendered":"<p>Reading Natasha Vargas-Cooper&#8217;s lively romp through the 1960s culture referenced in the TV series Mad Men, I came across Tim Siedell&#8217;s discussion of a witty, early 1960s advert by Doyle Dane Bernbach for Western Union telegrams, <a href=\"http:\/\/madmenunbuttoned.com\/search\/western+union\" target=\"_blank\" rel=\"noopener\">displayed here<\/a>.&nbsp;<\/p>\n<p>Seeing a telegram for the first time in about, oh, 35 years*, I looked at the structure.&nbsp;&nbsp; Note the header, with information about the company, as well as meta-information about the message.&nbsp;&nbsp; That structure immediately brought to mind the structure of a TCP packet.<\/p>\n<p>The Transmission Control Protocol (TCP) is the work-horse protocol of the Internet, and was developed by Vince Cerf and Bob Kahn in 1974.&nbsp;&nbsp; Their division of the packet contents into a header-part (the control information) and a data part (the payload) no doubt derived from earlier work on the design of packets for packet-switched networks.&nbsp;&nbsp; Later packets (eg, for IP, the Internet Protocol) were simpler, but still retained this two-part structure.&nbsp; This two-part division is also found in voice telecommunications at the time, for example in Common Channel Signalling Systems, which separated message content from information about the message (control information).&nbsp;&nbsp; Such systems were adopted internationally by the ITU for voice communications from Signalling System #6 (SS6) in 1975 onwards.&nbsp; In case the packet design seems obvious, it is worth considering some alternatives:&nbsp; the meta-information could be in a footer rather than in a header, or enmeshed in the data itself (as, for example, HTML tags are enmeshed in the content they modify).&nbsp; Or, the meta-data could be sent in a separate packet, perhaps ahead of the data packet, as happens with control information in Signalling System #7 (SS7), adopted from 1980. &nbsp;There are technical reasons why some of these design possibilities are not feasible or not elegant, and perhaps the same reasons apply to transmission of telegrams (which is, after all, a communications medium using packets).<br \/>\nThe first commercial electrical telegraph networks date from 1837, and the Western Union company itself dates from 1855 (although created from the merger of earlier companies).&nbsp; I don&#8217;t know when the two-part structure for telegrams was adopted, but it was certainly long before Vannevar Bush <a href=\"http:\/\/meeseeks:5080\/blog\/2010\/08\/as-we-once-thought\/\" target=\"_blank\" rel=\"noopener\">predicted the Internet<\/a> in 1945, and long before packet-switched communications networks were first conceived in the early 1960s.&nbsp;&nbsp; It is interesting that the two-part structure of the telegramlives on in the structure of internet packets.<br \/>\n<em>* Footnote: <\/em> As I recall, I sent my first email in 1979.<br \/>\n<em>Reference:<\/em><br \/>\nTim Siedell [2010]: &#8220;Western Union:&nbsp; What makes a great ad?&#8221; pp. 15-17 of:&nbsp; Natasha Vargas-Cooper [2010]:&nbsp; <em>Mad Men Unbuttoned<\/em>. New York, NY:&nbsp; HarperCollins.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Reading Natasha Vargas-Cooper&#8217;s lively romp through the 1960s culture referenced in the TV series Mad Men, I came across Tim Siedell&#8217;s discussion of a witty, early 1960s advert by Doyle Dane Bernbach for Western Union telegrams, displayed here.&nbsp; Seeing a telegram for the first time in about, oh, 35 years*, I looked at the structure.&nbsp;&nbsp; [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13,14,35,78],"tags":[],"class_list":["post-2265","post","type-post","status-publish","format-standard","hentry","category-computer-science","category-computer-technology","category-history","category-telecommunications","p1","y2010","m08","d17","h12"],"_links":{"self":[{"href":"https:\/\/vukutu.com\/blog\/wp-json\/wp\/v2\/posts\/2265","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vukutu.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vukutu.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vukutu.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/vukutu.com\/blog\/wp-json\/wp\/v2\/comments?post=2265"}],"version-history":[{"count":2,"href":"https:\/\/vukutu.com\/blog\/wp-json\/wp\/v2\/posts\/2265\/revisions"}],"predecessor-version":[{"id":10530,"href":"https:\/\/vukutu.com\/blog\/wp-json\/wp\/v2\/posts\/2265\/revisions\/10530"}],"wp:attachment":[{"href":"https:\/\/vukutu.com\/blog\/wp-json\/wp\/v2\/media?parent=2265"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vukutu.com\/blog\/wp-json\/wp\/v2\/categories?post=2265"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vukutu.com\/blog\/wp-json\/wp\/v2\/tags?post=2265"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}