CONTENTS Title Page Copyright Page Preface 1 Digital and SCSI 1.1 Why Digital Selected SCSI 1.2 Background 1.3 Commitment to Open Systems 2 Evaluating SCSI 2.1 Development Considerations 2.2 Systems with SCSI 2.2.1 NCR 5380 SCSI Interface 2.2.2 System Interface Interconnect (SII) 2.3 Features Implemented 2.4 Customer Support Services 3 Understanding SCSI-An Overview 3.1 The SCSI Bus 3.2 SCSI Bus Phases 3.3 SCSI Bus Signals 3.4 SCSI Device Controllers 3.5 The Common Command Set 4 Operating System Support 4.1 VMS SCSI Device Support 4.1.1 VMS SCSI Third-Party Device Support Mechanisms 4.1.2 SCSI Bus to IEEE488 Bus 4.1.2.1 Planning Software Support for the IEEE488 Bus-Converter 4.1.2.2 IEEE488 Bus-Converter Class Driver Interface Data Flow 4.2 ULTRIX SCSI Device Support 4.3 VAXELN SCSI Device Support 4.3.1 VAXELN SCSI Third-Party Device Support Mechanisms 4.3.1.1 Disk Device Class Driver 4.3.1.2 Message Class Driver 4.3.1.3 User-Written Class Driver A Associated Documents Glossary ANSI . . . connect controller . . . open system peripheral device . . . SCSI port SII . . . target FIGURES 3-1 SCSI Configuration 3-2 Bus Phases for INQUIRY Command 4-1 VMS SCSI Class/Port Interface 4-2 Data Flow from User to IEEE488 Device TABLES 2-1 Digital Systems and Associated Host Adapter 2-2 Digital's Implementation of SCSI 3-1 SCSI Bus Signals