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The University of Akron
Summit College
Business Technology Department
Computer Information Systems
2440: 145 Operating Systems
Introduction to UNIX/Linux
Instructor: Enoch E. Damson
Operating System
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The most important program running on a
computer
It helps:
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Store information
Process data
Use application software
Access all hardware attached to a computer
Control all the computer’s resources
Provide the basis upon which application
programs can be used or written
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Types of Operating Systems
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Different computer systems can have different
operating systems
For example:
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Operating Systems for Desktop PCs
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Microsoft Windows
Mac OS
Linux
Operating Systems for Server Computers
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Microsoft Windows 2000 Server
Microsoft Windows Server 2003
UNIX/Linux
NetWare
Mac OS X Server
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Types of Operating Systems…

Other operating systems include:

Operating Systems for Mainframes
IBMS’s MVS (Multiple Virtual Storage)
 z/OS


Operating Systems for Network Servers
Novell NetWare
 UNIX/Linux, Windows 2000/XP
 Windows Server 2000

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Types of Operating Systems…

Other operating systems include:

Operating Systems for Cellphones
Google Android
 Symbian
 Palm OS (HP WebOS)
 RIM Blackberry OS
 Apple iOS (iPhone)
 Windows Mobile

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Operating System Components

Some of the components of operating systems
include:
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Application Programming Interface (API) –
software designed to communicate with the
application software and the user
Basic Input/Output System (BIOS) – provides
the basic input/output functions to communicate
with system devices, such as monitors, keyboard,
disks, etc
Kernel – the core of the operating system that
coordinates operating system functions, such as
controlling memory and storage

Communicates with the BIOS, device drivers, and
the API to perform these functions and also
interface with the resource managers
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Operating System Components…

Other operating system components
include:
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Device drivers – programs that take requests
from the API via the kernel and translate them
into commands to manipulate specific
hardware devices, such as disks, keyboards,
monitors, printers, etc
Resource managers – programs that
manage computer memory and central
processor use
Optional drivers – for other functions and
devices, such as sound
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Characteristics of Operating Systems

One way to look at a computer and
operating systems is to consider them in
terms of one or more of the following
characteristics:
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Single-tasking
Multi-tasking
Time-sharing
Batch processing
Real-time
Multiuser
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Single Tasking Systems
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Executes only one process at a time
Generally restricted to
microcomputers and certain
specialized applications
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Multi-tasking Systems
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Executes more than one program at
a time for a user
It can run several programs in the
background while users are working
on another task in the foreground
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Time-sharing System
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A central computer system that is
used by multiple users and
applications simultaneously
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Mainframe computers typically fall into
this category
Most of the work is done in batches or
batch processes
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Batch Processing Systems
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Execute programs (batch process)
that do not require active user
intervention
Normally uses a noninteractive I/O
devices such as disks or document
scanners for input and returns
results to those same devices
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Real-time Systems
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An operating system that interacts
directly with the user and responds
in real time (immediately or almost
immediately) with required
information

Windows XP and Mac OS X are
examples of these systems
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Multi-user Systems
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Supports multiple users who are
accessing the computer’s and
operating systems’ hardware and
software facilities

Both time-sharing and real-time
systems can be multiuser systems
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Operating Systems Platforms

The main operating system
platforms include:
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Windows: by Microsoft Corporation
Mac OS: by Apple
UNIX
Linux
 Solaris

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The UNIX Operating System
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Multiuser, multitasking operating systems with built-in
network functions
Can be used on systems functioning as:
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Dedicated servers in a server-based network
Client workstations connected to a server-based network
Client/server workstations connected to a peer-to-peer
network
Standalone workstations not connected to a network
UNIX/Linux are:
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Multiuser systems – allow many people simultaneous
access and share the resources of a server computer
Portable – can be used in a variety of computing
environments
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A Brief History of UNIX/Linux

Developed in the 1970s by a group of
inventive scientists at Bell Laboratories.
The created an operating system
consisting of:
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Kernel – main program to control the CPU and
all other hardware
Utilities – a collection of user and system
programs
Filesystem – a structure for keeping and
locating data in files on the hard drive
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UNIX Versions
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There are two major versions of
UNIX:
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AT&T UNIX version V
Berkeley UNIX
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Other UNIX Systems
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There are several versions of UNIX
running on Sun, HP, IBM, etc that
are slightly different:
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Linux
Solaris
UnixWare
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Linux
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Linus Torvalds and other Internet
accomplices wrote Linux (a UNIX lookalike OS) and made it available for free in
its basic form
Versions of Linux include:
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Ubuntu
OpenSolaris
Fedora
Red Hat
OpenSuse
Knoppix
Debian
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Linux Shells
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Versions of UNIX shells include:
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sh – Bourne shell (UNIX 7th Edition)
bash – Bourne-again shell (GNU)
tcsh – Popular extension of the C shell
csh – C shell (BSD)
jsh – Job control shell (SVR4)
ksh – Korn shell (Bell Labs)
rsh – Remote shell (TCP/IP)
zsh – Popular extension of the Korn shell
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Linux GUI Desktops
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Mainstream desktop environments
for Unix-like operating systems using
the X Window System include:
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KDE
GNOME
LXDE
Xfce
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