{"id":128,"date":"2003-05-29T10:12:00","date_gmt":"2003-05-29T14:12:00","guid":{"rendered":"http:\/\/www.markbaker.ca\/wp\/?p=185"},"modified":"2003-05-29T10:12:00","modified_gmt":"2003-05-29T14:12:00","slug":"transport-transfer-and-coordination-generality","status":"publish","type":"post","link":"http:\/\/www.markbaker.ca\/blog\/2003\/05\/transport-transfer-and-coordination-generality\/","title":{"rendered":"Transport, transfer, and coordination generality"},"content":{"rendered":"

I was just reading over an article that gives a very\nhigh level overview of GXA<\/a>,\nwhich, like so many others, makes the fundamental mistake of talking about HTTP as\na “transport protocol”. Of course, one only need look at the\nHTTP spec<\/a> to see that it’s not,\nit’s a transfer<\/em> protocol, which is a very different beast; a coordination\nlanguage dealing in state.<\/p>\n\n

But after writing about coordination languages last night, something occurred to\nme; that the more general a transfer protocol, the easier it is to mistake it for\na transport protocol. HTTP, effectively, has only two methods; GET and POST, and\nthey are commonly confused with the semantics of send() and recv(). Other transfer\nprotocols, like SMTP, or IM protocols, are also\noften confused<\/a>\nwith transport protocols, for the same reason.<\/p>\n\n

Coordination languages come in very general and very specific flavours.\nWS-Transaction<\/a>\nis very specific, for example, as it deals only in “transactions”; any task\nwhich can be modelled as a transaction, can be accomplished with WS-Transaction.<\/p>\n\n

An example of a very general<\/em> coordination language, would be tuple space\nbased systems such as Linda<\/a>\nor Javaspaces<\/a>. These\nare general because they both deal in an abstraction known as a “space”. A\nspace is a more general abstraction than a “transaction”, because more things\ncan be modelled as spaces. But not every thing. For example, modelling a\nlightbulb as a space<\/a> leaves\none no way, without additional agreement, to check if the bulb is on or off.<\/p>\n\n

Of all the coordination languages that exist though, I suggest that there\nis one that is the most general, and it is REST’s “uniform interface”; it\ndeals in “resources”, which includes every thing.<\/p>","protected":false},"excerpt":{"rendered":"I was just reading over an article that gives a very high level overview of GXA, which, like so many others, makes the fundamental mistake of talking about HTTP as a “transport protocol”. Of course, one only need look at the HTTP spec to see that it’s not, it’s a transfer protocol, which is a […]","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-128","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/posts\/128","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/comments?post=128"}],"version-history":[{"count":0,"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/posts\/128\/revisions"}],"wp:attachment":[{"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/media?parent=128"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/categories?post=128"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/tags?post=128"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}