To: NED@sigurd.innosoft.com Cc: email@example.com, firstname.lastname@example.org, In-Reply-To: Ned Freed's message of Thu, 22 Oct 1992 22:39:33 -0700 <01GQ9KR9LCZ09D4EDD@SIGURD.INNOSOFT.COM> Subject: Re: misconceptions about MIME [long] From: Larry Masinter <email@example.com> Message-Id: <92Oct27.firstname.lastname@example.org> Date: Tue, 27 Oct 1992 14:38:18 PST I no longer know what forum to address this to, I suppose we've been asked to remove the discussion from 'email@example.com'. The arguments that in-band designation of document format is better than out-of-band information may apply in the electronic mail scenarios, where there is a single sender, multiple recipients, and the recipient has no control over what the sender might send. Instead, imagine, if you would, another scenario, of a WAIS or Web or anonymous FTP archive, which wishes to make available the latest version of the MIME specification. Let us suppose, in addition, that the publishing service has three different representations of the document, one marked "MIME rich-text", one marked "postscript", and one NetFax. Furthermore, let us suppose (as has been proposed) that the document types are marked by their MIME Content-type header designation. If I wish to retrieve the document, say to view it, I might want to choose the available representation that is most appropriate for my purpose. Imagine my dismay to retrieve a 50 megabyte postscript file from an anonymous FTP archive, only to discover that it is in the newly announced Postscript level 4 format, or to try to edit it only to discover that it is in the (upwardly compatible but not parsable by my client) version 44 of Rich Text. In each case, the appropriateness of alternate sources and representations of a document would depend on information that is currently only available in-band. I believe that MIME was developed in the context of electronic mail, but that the usage patterns in space and time of archives, database services and the like require more careful attention (a) to out-of-band information about format versions, so that you might know, before you retrieve a representation, whether you have the capability of coping with it, and (b) some restriction on those formats which might otherwise be uncontrollable. Finally, as much as I've tried to resist, I'll characterize your description of my response as 'repeated failure on your part to read the words I was writing' as 'inflammatory hogwash'.