Chapter 2 discusses client/server computing, focusing on the role of operating systems (OS) in managing hardware and software communication, resource allocation, and security. It classifies operating systems into categories like multi-user, multiprocessing, multitasking, and real-time, and explains the functions of network operating systems (NOS), which facilitate communication and resource sharing between multiple computers. Key services provided by both OS and NOS include user command execution, file management, access control, and network security.

1. C H A P T E R 2
C L I E N T / S E R V E R C O M P U T I N G
Client/Server Components

2. Operating System
 Is an important program that runs on every computer.
 Acts as an intermediary and allows communication
between hardware and software.
 Is a system software comprising fundamental files needed
to boot up and function ones computer.
 Performs basic task such as recognizing input from the
keyboard, sending output to the display screen, keeping
track of files and directories, controlling peripheral devices
etc.

3. Operating System
 Makes sure that different program and users running at the
same time do not interfere with each other.
 Is also responsible for security, ensuring that unauthorized
users do not get access to the system.

4. Services of OS
 Following are the main services of OS
 Carrying out commands of user and the application programs
 Supervising installation and running of other programs and
hardware
 Controlling the input output functions
 Allocating system resources such as memory, processor time,
disk space and peripheral devices to regulate the flow of work
within the computer

5. Services of OS
o Handling file and directory management
o Providing file sharing and networking functions

6. Classification of OS
 Multi-user
 allows two or more users to run the programs at the same time.
 E.g. a Unix server where multiple remote users have access to the Unix
shell prompt
 Multiprocessing
 Supports running a program on more than one CPU
 Multitasking
 Allows more than one program to run concurrently
 Real Time
 Responds to input instantly.
 A common example of RTOS is and HDTV receiver and display as it
needs to read a digital signal, decode it and display it as the data
comes in.

7. Network Operating System
 Is a computer operating system that are designed primarily
to support workstation, personal computer and in some
instances older terminal connected through LANs.
 Is a software that allows multiple computers to
communicate, share files and hardware devices with one
another.
 Provides services to clients over network
 E.g. Novell NetWare, Microsoft Windows NT, Sun Solaris,
Linux etc

8. Services of NOS
 Both the client/server and peer to peer networking models
uses network operating system and such a system must be
able to perform following duties.
 Providing access to remote devices, managing which users are
using which device and when
 Enabling and managing access to files on remote system and
determining who can access what and who can’t
 Granting access to remote applications and resources such as
internet and making those resources seem like local resources
to the user

9. Services of NOS
 Providing routing services so that the operating system
knows what data to send where
 Monitoring the system and security so as to provide
proper security against viruses, hackers and data
corruption
 providing basic administrator utilities, enabling an
administrator to perform task involving managing
network resources and users.