Nelson’s paper tried to envisage ‘a computer system for personal information retrieval and documentation’. Nelson knew about and had referenced Bush’s Memex, but understood that, although the required hardware was becoming available, the software required was not being developed.
Nelson wanted to design his system around the system used by a writer:
‘The task of writing is one of rearrangement and reprocessing, and the real outline develops slowly. The original crude or fragmentary texts created at the outset generally undergo many revision processes before they are finished. Intellectually they are pondered, copied, overwritten with revision markings, rearranged and copied again. This cycle may be repeated many times. The whole grows by trial and error in the processes of arrangement, comparison and retrenchment. By examining and mentally noting many different versions, some whole but most fragmentary, the intertwining and organizing of the final written work gradually takes place’, (Nelson 1965).The preliminary specifications of the system were as follows:
- ‘It would provide an up-to-date index of its own contents (supplanting the “code book” suggested by Bush)’, (Nelson 1965).
I think Nelson misunderstands Bush here. I read the Memex’s ‘code book’ or ‘code space’ to be equivalent to the HTML behind a web page. A space that is programmable by the site designer, but otherwise not seen by the user, who, as Bush described, only has to activate the link to bring up the linked item. Here Nelson tries to describe a traditional style index that updates itself. - ‘It would accept large and growing bodies of text and commentary, listed in such complex forms as the user might stipulate’, (Nelson 1965).
- ‘It would file under an unlimited number of categories’, (Nelson 1965).
This requirement seems to be satisfied by modern day meta tags. - ‘Besides the file entries themselves, it would hold commentaries and explanations connected with them’, (Nelson 1965).
This is a requirement that Tim Berners Lee wanted to try to establish with the World Wide Web and the idea behind the W3C’s Amaya project. Although in the Web 2.0 world we seem to be accomplishing this through commenting boxes on the same web page as the item in question.
Nelson revisits the same point later in his paper, explaining that:
‘The user must be permitted, given a list of what he has done recently, to undo it. It follows that “destroy” instructions must fail safe; if given accidentally, they are to be recoverable. For safety’s sake, it should take several steps to throw a thing away completely. An important option would permit the user to retrace chronologically everything he does on the system’, (Nelson 1965).If we consider that the item in question is a web page, then perhaps we could have a meta-tag in the mark-up that identifies different web pages that are associated with it, e.g. different versions of the same page. There is no limit to the amount of meta-tags we can place in a page, or what they contain, so we could also use these tags to identify pages in entirely different locations that relate to the same set.
Another possibility is that the top level file is actually a package. Within this package are contained different versions of the web page. This would allow us to roll-back and forth through changes as required. This option would require web browsers to be adapted in order to extract the relevant page from the package before viewing.
Storage of multiple versions of a document allows us another development, mooted by Nelson:
‘Systems of paper have grave limitations for either organizing or presenting ideas. A book is never perfectly suited to the reader...This specification resulted in what Nelson called an ‘evolutionary file structure: a file structure that can be shaped into various forms, changed from one arrangement to another in accordance with the user’s changing need’, (Nelson 1965). Nelson proposed the ‘Evolutionary List File, or ELF’ as a system used to implement an evolutionary file structure.
However... a new, readable medium... will let the reader find his level, suit his taste and find the parts that take on special meaning for him, as instruction or entertainment’, (Nelson 1965).
‘The ELF has three elements: entries, lists and links...We can consider that the ELF equates to the World Wide Web, an entry to a Web Page, a list to a Website and, of course, a link is a link.
- An entry is a discrete unit of information designated by the user...
- A list is an ordered set of entries...
- A link is a connector, designated by the user, between two particular entries which are in different lists’, (Nelson 1965).
Nelson theorised features of entries, lists and links:
Entries (or modern day web page):
‘An entry in one list may be linked to only one entry in another list’...Lists (or modern day website):
‘Entries may be combined or divided... Entries may be put in any list, and the same entry may be put in different lists. The user may direct that entries of one list be automatically copied onto another list, without affecting the original list’...
‘It would be possible to allow sub-entries and super-entries to behave and link up like normal entries, even though they contained or were contained in other entries’, (Nelson 1965).
‘A change in the sequence of either list, or additions to either list, will not change the links that stand between them’...Links:
‘[The user] may at will make new copies of lists. [The user] may rearrange the sequence of a list, or copy the list and change the sequence of that copy. Lists may be combined; lists may be cut into sublists’ , (Nelson 1965).
‘Changes in the link structure will occur only if the user specifically changes the links, or if he destroys entries which are linked to others’...Nelson highlighted that there is a problem when an entry is disposed of ‘what other lists is an entry on?’ Programmed bots now roam the web carrying out simple tasks. Surely a bot could be made to constantly check the links within one website in order to check that they are not ‘dead links’ and if they are to remove the underlying link and highlight the issue to the administrator.
‘Any number of legal links may be created, although the upper limit of links between any two lists is determined by the 1-for-1 rule. When an entry or a list is copied into a list, links will remain between parent and daughter entries. Moreover, after a list-copying operation, the daughter list will have the same links to all other lists as does the parent list’, (Nelson 1965).
Uses of the ELF? Even though we now know what the Web can be used for, the following section makes interesting reading:
‘the ELF may be used as a glorified card file.. . [This permits] assignment of one entry to different lists. It permits sub-sets and sub-sequences for any use to be held apart and examined without disturbing the lists from which they have been drawn, by copying them onto other, new lists. The ELF permits the filing of historical trails or associative (Bush) trails... and the mixture of trail with categorical filing’, (Nelson 1965).There is a hint of a, so-far unexplored, feature in the above paragraph. He later expands:
‘the ELF is capable of storing many texts in parallel, if they are equivalent or linked in some way. For example, instruction manuals for different models of the same machine may be kept in the file as linked lists and referred to when machines are to be compared, used or fixed. This is of special use to repairmen, project managers and technical writers’, (Nelson 1965).The point I am picking up on, is the ability to compare data. Is it not possible for us to develop applications that take two different pages, even their code, and compare them so we can see where the differences are? This could be a particularly useful feature if they are versions of the same page. Or perhaps if they followed a standard layout used in a specific industry. From comparing layouts we could even suggest sections that have been missed or otherwise aid the author.
With this specification, Nelson had to create a new definition:
‘Let me introduce the word “hypertext” to mean a body of written or pictorial material interconnected in such a complex way that it could not conveniently be presented or represented on paper’...Lastly, Nelson provides a warning to future computer scientists:
‘The sense of “hyper-“ used here connotes extension and generality; cf. “hyperspace.” The criterion for this prefix is the inability of these objects to be comprised sensibly into linear media, like the text string, or even media of somewhat higher complexity”, (Nelson 1965).
‘Last week’s categories, perhaps last night’s field, may be gone today...
Categories are chimerical (or temporal) and our categorisation systems must evolve as they do. Information systems must have built-in the capacity to accept the new categorisation systems as they evolve from, or outside, the framework of the old. Not just the new material, but the capacity for new arrangements and indefinite re-arrangements of the old, must be possible’, (Nelson 1965).
- Nelson, T. H., 1965. Complex information processing: a file structure for the complex, the changing and the indeterminate. In: Proceedings of the 1965 20th national conference, August 24-26, 1965, Cleveland, Ohio, United States. New York, NY, USA: Association for Computing Machinery, 84-100. Available from: http://doi.acm.org/10.1145/800197.806036 [Accessed 08 January 2008].
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