by Darius Kazemi, October 21 2019

In 2019 I'm reading one RFC a day in chronological order starting from the very first one. More on this project here. There is a table of contents for all my RFC posts.

Negotiating data types

RFC-294 is titled “The Use of 'Set Data Type' Transaction in File Transfer Protocol”. It's authored by Abhay Bhushan of MIT and dated January 25, 1972.

The technical content

The transcription of this RFC is incomplete and somewhat garbled so it's a little hard to interpret, but the gist of it is that Bhushan wants the “set data type” operation in the latest File Transfer Protocol, RFC-265 to be clarified, at least in the case of retrieving data.

As it's laid out in RFC-265, “set data type” is a command that identifies the data type and byte size of any following transactions. Bhushan says that this isn't clear and says that if it precedes a retrieve request, the server should interpret that as a request from the user to get data in a certain format, but that the request can be denied. Unfortunately the transcription cuts off at the point of saying what the denial should look like, though from the figure on page two I can guess that the server should send back its own “set data type” notification that tells the user what to expect instead.

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About me

I'm Darius Kazemi. I'm an independent technologist and artist. I do a lot of work on the decentralized web with ActivityPub, including a Node.js reference implementation, an RSS-to-ActivityPub converter, and a fork of Mastodon, called Hometown. You can support my work via my Patreon.