MACE: a fine grained concurrent editor

Abstract

MACE is a distributed program running on the X Window System and Unix 4.3bsd2 sockets that permits fine-grained (character-level) concurrent editing of text files. It runs both as a stand-alone program and as an application in the University of Florida’s distributed conferencing system (DCS). MACE uses write locks for concurrency control, allowing a locked section of text to be bounded by any pair of characters in the file. Multiple users may read or edit a file concurrently, with all users receiving updates whenever a lock is removed. The level of sharing is controlled by mutual consent, so that users may collaborate e to the degree desired, including the option to view updates in real time. MACE is a first step towards a fine-grained, lock-based approach to concurrent text editing. Permission to copy without fee all or part of this material is that copying is by permission of the Association for Computing granted provided that the copies are not made or distributed for Machinery. To copy otherwise, or to republish, requires a fee direct commercial advantage, the ACM copyright notice and the and/or specific permission. title of the publication and its date appear, and notice is given @ 1991 ACM 0-89791 -456-2 /91/0010 /0240 . ..$1 .50 ] This work is partially supported by the University of Florida PurdueUniversity Software Engineering Research Center. 2Unix is a trademark of AT&T Bell Labs, 3nemo@chameleon .cis. ufl.edu