CMOS Configuration Chip

Jumpers

Software
The intelligence of the computer
Computer programs, or instructions to perform a specific task
Determines what hardware is present
Decides how hardware is configured and utilized
Uses hardware to perform tasks

Three Types of Software and What They Do
Firmware (BIOS)
Controls computer’s input/output functions
Operating systems (OSs)
Provide instructions to hardware to perform tasks
Applications software

Functions of BIOS and OS

Firmware or BIOS
Provides basic instructions to hardware
Often serves as the interface between higher-level software and hardware

Software Layers
A hierarchy determines how software interfaces so that high-level software can depend on low-level software to manage the hardware for it
Applications software depends on the OS to interface with hardware
Instructs hardware directly
Uses BIOS to provide the instructions
Uses device drivers

Software Layers

How Software Manages and Shares Information

Operating Systems
Different operating systems are written to support different types of hardware systems and user needs

Functions of Operating Systems
Manage BIOS
Manage files on secondary storage devices
Manage primary memory (RAM)
Diagnose software and hardware problems
Interface between hardware and software
Perform housekeeping procedures requested by user

Starting Up the Operating System
OS programs must be copied from secondary storage into RAM (memory)
CPU then reads from one memory location in RAM to another to receive and follow instructions

Starting Up the Operating System

Interfacing with the Operating System
Command-driven interface
Menu-driven interface
Icon-driven interface (graphical user interface or GUI)

Command-driven Interface

Menu-driven Interface

Icon-driven Interface

Survey of Operating Systems
Terms
Multitasking
Cooperative multitasking (task switching)
Preemptive multitasking
Environment
Windows 3.x operating environment

Multitasking Environment

Windows 3.x Operating Environment

Comparison of Operating Systems
What kind of user interface is provided?
Can the OS support multitasking?
Can the OS easily manage large quantities of primary memory (RAM) and secondary storage?
How many and what kinds of applications are written to work with the OS?
How powerful must the hardware be to make efficient use of the OS?
How does the OS perform in a network?

Well-known Operating Systems
DOS (disk operating system)
DOS with Windows 3.1 and 3.11 operating environments
Windows 95 and Windows 98
UNIX operating system
Windows NT
Windows 2000
OS/2
Macintosh operating system

Disk Operating System (DOS)
First OS used by IBM microcomputers

Disk Operating System (DOS)