United States Patent  [ii] Patent Number: 4,783,761
Gray et al.  Date of Patent: Nov. 8, 1988
 SPELLING CHECK DICTIONARY WITH EARLY ERROR SIGNAL
 Inventors: R. William Gray, Ithaca; Donald T.
Adams, Homer, N.Y.; Howard C.
Duncan, IV, Marathon, all of N.Y.
 Assignee: Smith Corona Corporation, Cortland,
 Appl. No.: 813,351
 Filed: Dec. 26, 1985
 Int CI* G06F 7/04
 U.S. CI 364/900
 Field of Search ... 364/900 MS File, 200 MS File;
 References Cited
U.S. PATENT DOCUMENTS
4,328,561 5/1982 Convis et al 364/900
4,383,307 5/1983 Gibson, III 364/900
4,498,148 2/1985 Glickman 364/900
4,499,553 2/1985 Dickinson et al 364/900
4,651,300 3/1987 Suzuki et al 364/900
Primary Examiner—Gareth D. Shaw
Assistant Examiner—Debra A. Chun
A method and apparatus for adding a low-cost spelling check dictionary feature to document preparation systems such as portable electronic typewriters, the spelling check being performed on a character-by-character basis and an error signal emitted upon the earliest determination that an input character does not conform to that of any word listed in the dictionary. Semiconductor ROM is used for storage of the dictionary listing and for program control of the spelling check. Text compression methods are utilized to permit storage of large vocabularies (about 35,000 words) while minimizing the ROM capacity required (about 3 IC's of 256K bits each).
11 Claims, 5 Drawing Sheets