A pilot study was performed to experimentally assess the implications of Cathode Ray Tubes (CRT) screen size and definition on text editing performance. The study manipulated line length (16, 32, and 64 characters displayed per line), window height (1, 4, 8, and 19 line text pages), and edit field location (text to be edited was located at the beginning, middle, or end of text messages) to measure effects on text editing performance as measured by edit field location time, editing time, and errors. Of these, text location time and location errors (as measured by vertical scroll reversals) were significantly influenced by line length and edit field location. Keywords: User computer interface, Human factors engineering, Soldier computer interface, Screen size, CRT information display, Text editing performance. (SDW).

A pilot study was performed to experimentally assess the implications of CRT screen size and definition on text editing performance. The study manipulated line length (16, 32, and 64 characters displayed per line), window height (1, 4, 8, and 19 line text pages) and edit field location (text to be edited was located at the beginning, middle, or end of text messages) to measure effects on text editing performance as measured by edit field location time, editing time, and errors. Of these, text location time and location errors (as measured by vertical scroll reversals) were significantly influenced by line length and edit field location. Keywords: User-Computer Interface; Human Factors Engineering; Soldier-Computer Interface.

Text-editing performance on a visual display screen was studied as a function of five different window heights (1, 4, 8, 16, and 23 lines) and three different message lengths (short=1 line, medium =10-15 lines, and long = 23 lines). Performance and attitude data were collected on 30 subjects. A multivariate analysis of variance (MANOVA) conducted on the performance data revealed a significant main effect for message length but not for window height nor for the interaction between these two variables. Subjects took longer to locate text in medium and long messages than in short messages. A second MANOVA revealed that regardless of window-height condition, subjects' general attitudes toward computers became more positive following their interactions with the computer. Taken together, the results indicate that people's text-editing performance and attitudes are not adversely affected as the amount of text that is displayed on a computer screen is reduced. Therefore, depending on the task, larger computer screens may not offer significant advantages to users. Keywords: man computer interface; Small screens.