JOT

JOT (Juggler Of Text) was an experimental word processor / text editor / notation program created by Ted Nelson (of Project Xanadu fame) and his associates as an attempt to embody how Nelson believed the creation and editing of computerized text ought to be done. Never released as a product, it had a number of experimental versions in the 1970s and 1980s, with version 0.53 for the Apple II platform (1986) its latest known version.

As envisioned by Nelson, JOT would move gracefully through a text document by logical units of words, sentences, and paragraphs, with increasingly abbreviated versions of parts of the document above and below the cursor showing summaries of distant document parts and full detail of near ones, changing smoothly as you move around. Technology of the day didn't fully allow this dream to be implemented, however.

File format
An examination of the raw bytes of the 0.53 disk dump (linked below) yields some clues about the format in which text was stored. The sample document loading upon startup of this version begins at offset 9400 (hex) (sector boundaries in Apple II 5.25" disks represented in DSK format are at the hex numbers ending in "00").

The document begins with a number of null (00) bytes, 51 (decimal) of them to be exact. Perhaps this was padding to allow the early part of the document to be moved backward to accommodate insertions, which would be faster in some cases than moving the later part forward if the insertion is nearer the beginning. Then the text follows, with ASCII characters having their own normal values (except that capital letters at the start of sentences are stored as lowercase, with capitalization performed upon display by JOT's algorithm; other capitals such as in proper names, acronyms, or emphasized "shouted" words are stored as actual capitals). However, word, sentence, and paragraph breaks are represented using special characters in the 8-bit range of 80 - FF (all character code points here are given as hexadecimal).


 * 80 represents a word break (displayed as a space).
 * A0 represents a paragraph break (displayed as a line break followed by an indent).
 * 90 represents a sentence break (displayed as two spaces, with the first letter of the next sentence capitalized).
 * F0 represents the end of the document (or chapter?)

Links

 * In-browser emulation (v0.53, Apple II, 1986) (JSMESS)
 * Disk image download of above version (DSK format)
 * Discussion in a 1980 Creative Computing article