User Interface Design Issues for a
Large Interactive System 1

Abstract 2
Introduction 3
High Level Assumptions Underlying the Design of the NLS User Interface 4
Some Command Language Considerations 5
The NLS Command Language 6
Help, Status, and Portrayal Facilities 7
Error Messages and Recovery 8
Editing and Backup During Command Specification 9
Implementation 10
Acknowledgment 11
References 12
Key Words 13