Transcript Systems Software

Systems Software
Unit 2
What is Software?
 Intangible
 A file
 Performs tasks / jobs
 A set of instruction
 Run/executed by the Central
Processing Unit (CPU)
 Must be in the computer’s memory
to run
Two Types of Software
Systems Software
Applications Software
What is Systems Software
 Controls the system
 Hardware
 Software
 Input / Output (I/O)
 Middle man
 Comprised of
 Operating system
(OS)
 Utility Programs
Platform
Computer processor & operating
system
Flavor
Version of an operating system
Systems Software Programs
 Mainframe computers
Unix
 Desktop / Laptop computers
Windows
Mac OSX
Linux
Unix
 Bell AT&T labs - 1969
 Runs on large computers
Windows
 Microsoft
 Windows ME
 Bill Gates
 Windows 2000
 Leading market share
 Windows NT
 Windows 3.1
 Windows XP
 Windows 9
 Windows Vista
 Windows 98
 Windows 7
Mac OSX
 Apple
Computers
 Steve Jobs
 Control
hardware &
software
 Based on Unix
Linux
 Linus Tovalds - 1991
 Open source
 Based on Unix
 Free
 Distros
Operating System Parts
 Kernel
Heart of the operating system
Must be in memory while the
computer is running
All the important tasks the OS must
do
 User Interface
How a human gives commands to
the OS
Types of Operating Systems
 Classify by Users
Single User
Multiple User
 Classify by Task
Single Task
Multitasking
 Real-time Systems
Operating System Jobs
 Controls the
hardware
 Controls all the other
software programs
Managing the Processor
 Controls the timing of events the
processor works on
REQUEST
Operatin
g
System
Managing Memory
 The operating system allocates space in RAM
for instructions and data
RAM
Operating
System
Managing Peripheral Devices
 Co-ordinates system hardware
 Device drivers
Small programs
How to communicate with a device
 Plug and Play
Device device drivers included with systems
software
Makes devices immediately usable
Managing Storage
 Handles where files are
placed on a storage
device
 Retrieves files from
storage device & puts
them in memory
 Remembers file details
 File allocation table /
File allocation system
Application Software Interface
 Requests made by application programs
to the OS
Save a document
Print a document
Open a document
Send an e-mail
Play a song
User Interface
 Enables you to interact
with the computer
 Types of interfaces:
 Command-driven
interface
 Menu-driven interface
 Graphical user interface
Utility Programs
 Additional small programs
 Maybe added on later
 Help with maintenance
 Make the computer easier to use
Task Scheduler
Defrag
Screen savers
Install/ uninstall wizard
The Boot Process
 Step 1: The basic input/output system
(BIOS) is activated
 Step 2: A power-on self-test (POST)
checks attached hardware
 Step 3: The operating system loads into
RAM
 Step 4: Configuration and customization
settings are checked