Tumblers were proposed by Ted Nelson in "Literary Machines" as a means to address every bit ever written, or a particular span of bits in any text ever written.
A tumbler is a unique numerical address of an interesting artefact. The address resembles IP-Addresses, but is much larger and has much more detailed structure. The structure looks like this.
1. < node >.0. < user >.0. < document >.0. < element >
The "1." is used in order to mark the start of a new address. The individual fields of the address are divided with ".0." so that they can be arbitratily long. Each < element > has the format "n. n. ... . n" , a hierarchy of subaddresses.
The last element denotes the special kind of element, for example:
1. Text/Bytes 2. Links 3. Bitmaps 4. etc.
{| | Address area || Tumbler Address || Comment |- | Node || 1.2368.792.6 || This is the computer with the number 2368.792.6 |- | User || 1.2368.792.6.0.6974.383.1988.352 || This is user 6974.383.1988.352 on the above computer. |- | Document || 1.2368.792.6.0.6974.383.1988.352.0.75 || The user's document number 75. |- | Version || 1.2368.792.6.0.6974.383.1988.352.0.75.2 || Version 2 of the document. |- |}
The 9287th byte of this version of the document would be 1.2368.792.6.0.6974.383.1988.352.0.75.2.0.1.9287 and the 356th link would be 0.2.356 on the end instead.
Tumblers are only issued once and never changed again. The structure can grow at will, the address space is practically infinite.
Nelson also introduces the concept of "spans", and the idea of direction. One can speak of "2 chapters back" or "300 bytes forward".
More information:
* The Xanadu model:
http://xanadu.com/zigzag/fw99/XUmodel.html
* Definitionen:
http://www.sunless-sea.net/wiki/Definitions
* Theodor Holm Nelson: Xanalogical Structure. Needed Now More than Ever: Parallel Documents, Deep Links to Content, Deep Versioning, and Deep Re-Use:
http://www.cs.brown.edu/memex/ACM_HypertextTestbed/papers/60.html
* Theodor Holm Nelsons Homepage:
http://ted.hyperland.com/
