In 1968 Andries van Dam and his students at Brown University, including Bob Wallace, introduced The File Retrieval and Editing SyStem, or FRESS. FRESS was a continuation of work done on van Dam's previous hypertext system, HES, developed in 1967.
"FRESS ran on an IBM 360-series mainframe running VM/CMS. It implemented one of the first virtual-terminal interfaces, and could run on various terminals from dumb typewriters up to the Imlac PDS-1 graphical minicomputer. On the PDS-1, it supported multi-window WYSIWYG editing and graphics display. Notably, the PDS-1 used a lightpen rather than a mouse, and the lightpen could be "clicked" using a cathartic foot-pedal.
"FRESS improved on HES's capabilities in many ways. FRESS documents could be of arbitrary size, and (unlike prior systems) were not laid out in lines until the moment of display. FRESS users could insert a marker at any location within a text document and link the marked selection to any other point either in the same document or a different document.
"FRESS had two types of links: tags and "jumps". Tags were links to information such as references or footnotes, while "jumps" were links that could take the user through many separate but related documents, much like the World Wide Web of today. FRESS also had the ability to assign keywords to links or text blocks to assist with navigation. Keywords could be used to select which sections to display or print, which links would be available to the user, and so on. Multiple "spaces" were also automatically maintained, including an automatic table of contents and indexes to keywords, document structures, and so on.
"FRESS is also possibly the first computer-based system to have had an "undo" feature for quickly correcting small editing or navigational mistakes.
"FRESS was essentially a text-based system and editing links was a fairly complex task unless you had access to the PDS-1 terminal, in which case you could select each end with the lightpen and create a link with a couple of keystrokes. FRESS provided no method for knowing where the user was within a collection of documents.
"FRESS was used for instructional computing (probably being the first hypertext system used in education), particularly for teaching poetry, as well as typesetting many books, notably by philosopher Roderick Chisholm. For example, in the Preface to Person and Object Chisholm writes 'The book would not have been completed without the epoch-making File Retrieval and Editing System...' FRESS was for many years the word processor of choice at Brown and a small number of other sites " (Wikipedia article on File Retrieval and Editing System, accessed 11-08-2013).