Theory of Operation 4-1
4Theory of Operation

4.1 Introduction

This section contains a general block diagram theory of operation description of the
Extensa 900 Series Notebook Computers.
Note: Various internal components may change on future models and
busses/bus speeds are subject to change.

4.2 Notebook Functional Overview

The Extensa 900 Series Notebooks consist of eight major functions or sections
including:
System Processor — implemented on the Main Board Assembly
Memory Subsystem — implemented on the Main Board Assembly
I/O Subsystem — implemented on the Main Board Board
Keyboard Subsystem — implemented on the Main Board Assembly and the
Keyboard Assembly
Video Subsystem — implemented on the Main Board and LCD Display Panel
assemblies
Sound Subsystem — implemented on the Main Board Assembly
Touchpad Mouse Subsystem — implemented on the Touchpad assembly and
on the Main Board Assembly
Hard Disk Drive Subsystem — implemented on the Main Board Assembly and
the Hard Disk Drive Assembly
Floppy Disk Drive Subsystem — implemented on the Main Board Board and
Floppy Disk Drive Assembly
PCMCIA Controller and Sockets — implemented on the PCMCIA Module and
on the Main Board
Power Subsystem — implemented on the Main Board, the battery pack, and
the AC adapter