Fundamentals Of Information Systems
Media A. Ibrahim
MSc: Software Engineering
ISE Department
Media.ibrahim@epu.edu.krd
2019-2020
1
Defining information systems(technology)
Hardware: input devices, processing, and output devices.
Software :System software and application software.
2
Outlines
• Computer Hardware
• Central Processing unit(CPU)
• Primary storage (main memory; memory)
• Secondary storage
• Input devices
• Output devices
3
Computer Hardware
Hardware describes the physical components of a computer system, which
can be categories as Input devices, output devices, memory and Central
processing unit, etc.
Figure 3-1 Computer System Components 4
Hardware Components (Continued…)
Hardware Components
in Action
• Step 1: Fetch instruction
• Step 2: Decode instruction
• Step 3: Execute the instruction
• Step 4: Store results
5
CPU
CPU is the abbreviation for central processing unit.
Sometimes referred to simply as the central processor, but
more commonly called processor, the CPU is the brains
of the computer where most calculations take place. In
terms of computing power, the CPU is the most important
element of a computer system.
Converts data into information
Reading instructions from RAM and executing them
5
Components of CPU
The CPU Consists of:
–Control Unit
–Arithmetic Logic Unit (ALU)
–Registers (high-speed memory)
•Program Counter (PC)
•Instruction Register (IR)
Figure 3-2 CPU Components 7
Control Unit
CU
• Handles the transmission of data into and out of the
CPU and supervises its overall operations.
• Communicates with other parts of the hardware
8
Arithmetic / Logic Unit
ALU
Performs arithmetic operations
Performs logical operations
9
Arithmetic Operations
Addition
Subtraction
Multiplication
Division
10
Logical Operations
• Evaluates conditions
• Makes comparisons
• Can compare
– Numbers
– Letters
– Special characters
11
Registers
Registers
– The CPU contain special storage areas called registers.
– Their function is to hold instructions, data values, memory
addresses of both the instructions and data.
There are 4 basic types of it:
1. Instruction register hold instruction
2. Address register hold address of( data , next instruction ).
3. Storage register store data retrieved from main memory
prior to processing.
4. Accumulator store the results of arithmetic & logic
operations
12
Memory Characteristics and Functions
Memory, also called primary storage, is located physically
close to the CPU to decrease access time, that is, the time it
takes the CPU to retrieve data from memory. Memory
temporarily holds instructions and data before and after
processing by the CPU. Although the overall trend has been
increased memory access time, memory has not advanced as
quickly as processors. Memory access time is often measured
in milliseconds, or one thousandths of a second.
13
Storage Capacity
Figure 3-3Memory Capacity
14
Types of Memory
Figure 3-4 Memory Chips Types
15
Types of Memory(Continued…)
Types of RAM (Random Access Memory)
EDO (Extended Data Out)
DRAM (Dynamic RAM)
SDRAM (Synchronous DRAM)
• Although “EDO” RAM is the primary type of RAM, synchronous
dynamic RAM can be accessed faster.
• RAM technology has not improved as rapidly as microprocessor technology.
16
Types of Memory(Continued…)
Types of ROM
ROM (read-only memory)
PROM (programmable read-only memory)
EPROM (erasable programmable read-only memory)
17
Difference Between RAM & ROM
Figure 3-5 Difference Between RAM & ROM
18
Secondary Storage
Secondary storage devices
Store a larger amount of data or instructions then does main memory, on a
more permanent basis.
On a per megabyte basis, secondary storage is also cheaper than primary
storage.
Secondary storage is also infinitely extendable, unlike main memory,
which is finite.
Secondary storage is not volatile.
Secondary storage is also more portable than primary storage – that is, it
is possible to remove it from a computer and use the device and its
contents in another .
19
Secondary Storage (Continued..)
Access Methods
Data and information can be retrieved from secondary storage in two main
ways. Access can be either sequential or direct.
Sequential: records must be retrieved in order
Devices used are called sequential access storage devices (SASD)
Direct: records can be retrieved in any order
Devices used are called direct access storage devices (DASDs)
20
Classification of Commonly Used Secondary Storage Devices
Figure 3-6a Secondary Storage
Devices
21
Classification of Commonly Used Secondary Storage Devices
Figure 3-6b Secondary Storage
Devices
22
Input and Output Devices
Input devices are all
those hardware Output devices
equipment that are used are ability to
to enter data into the read/see/use what
computer. the computer is
Input devices captures doing
information and translates Any type of
it into a form that can be device that provides
processed and used by data from a
other parts of your computer to the
computer. outside world
Examples: Examples:
Keyboards Monitor
mouse Printer
Scanners Figure 3-7 Input and
Speakers
Output Devices
Figure 3-7 Input and Output Devices
23
Defining information systems(technology)
Hardware: input devices, processing, and output devices.
Software :System software and application software.
24
Outlines
• Computer Software
o System software
• Operating Systems
• Utility Programs
• Software development programs.
o `Application Software
25
Computer Software
• Software can be defined as a series of detailed
instruction that control the operation of a computer
system and exists as programs which are developed
by computer programmers.
• Some of the personal tasks that can be done by
using software are:
– Internet research
– Games
– Keeping a budget
– Income tax preparation
26
Computer Software(cont.)
There are two major categories of software:
1. System software
2. application software
27
System software
• System Software is an interface between users,
application software and hardware.
• Generalized programs that manage the computer’s
resources, such as the central processor,
communications links, and peripheral devices.
• .The main role of System Software is to communicate
with hardware.
28
System software(cont.)
• System Software consists of:
– Operating Systems
– Utility Programs
– Software development programs.
29
Operating System
• Operating System is a software, which makes a computer to
actually work.
• The operating system is a program that is always running on
the computer.
• It is the software the enables all the programs we use.
• The OS organizes and controls the hardware.
• OS acts as an interface between the application programs and
the machine hardware.
• Examples: Windows, Linux, Unix and Mac OS, etc.,
Types of OS
Microsoft Windows
Mainframe
DOS
OS/2
Linux
Mac OS
What the Operating System Does
The User Interface
• Enables user to interact
with the computer
• Types of interfaces
– Command-driven interface
– Menu-driven interface
– Graphical user interface
(GUI)
32
Operating System (cont.)
Types of Operating System:
Single-tasking
DOS
Multi-tasking
Windows 8
Mac OS
UNIX
Network Operating Systems:
NetWare
UNIX
Window Server
33
Utility Programs
• Utility programs help to manage, maintain and
control computer resources.
• Examples of Utility programs:
– Backup software
– Scandisk
– Virus scanning software
34
Software development programs
• Software development programs allow users to
develop their software in order to carry out
processing tasks using programming language.
35
Application Software
• Application software helps users to solve a particular
problem.
• It consists of programs that direct computers to
perform specific information processing activities for
end users.
• Application software can also e stored on CDs ,
DVDs, and flash
36
Application Software(cont.)
• Types of Application Software are:
Word Processing Software
Spread sheet Software
Presentation Software
Database Software
Multimedia Software
37
Conclusion
• Hardware and software are two important
components of IS.
38
