AT&T DOS-73 Technical Reference free download

File name DOS-73_Technical_Reference.pdf

PREFACE INTENDED AUDIENCE The DOS-73 Technical Reference is written for technicians doing component-level trou bleshooting of the DOS-73 Coprocessor board. ORGANIZATION OF THIS MANUAL System Features and Functions Briefly describes the physical features and functional capabilities of the DOS-73 Coprocessor board. DOS-73: Theory Of Operation Describes the DOS-73 hardware and the functions performed by it. Diagnostics Describes DOS-73 Coprocessor diagnostic procedures. 1. CONTENTS 1: System Features and Functions General Description... 1-2 DOS-7 3 Archi tecture... 1-2 DOS-73 Block Diagram... 1-3 2: DOS-73: Theory Of Operation cPu... 2-2 Memory Organization... 2-3 COM2: Emula tion... 2-4 Timer Emulation... 2-5 Interrupt System... 2-5 I/O Intercept System... 2-6 Video Intercept System... 2-7 Math Coprocessor Emulation... 2-7 UNIX Interface... 2-8 Software Driver Specifications...