Page 619 - Introduction to Business

CHAPTER 17 Management Information Systems 593

An information system is a system that converts data into information. Some information system A system that
information systems use computers, and some information systems do not use converts data into information
computers. We will concentrate on computer-based information systems. Manage- management information systems The
ment information systems (MISs) are the systems that manage the direct systems that manage the direct
resources needed for creating, storing,
resources needed for creating, storing, and distributing information in a business and distributing information in a
organization. The direct resources that MISs manage include computer hardware, business organization
computer software, databases, and telecommunications networks.

reality Can you think of some applications of management information sys-
CH ECK tems in your college or university?

Computer Hardware

LEARNING OBJECTIVE 2
Describe the roles that computer hardware, computer software, databases, and
telecommunications networks play in management information systems.

A modern computer system includes a central processing unit, primary storage, sec-
ondary storage, input devices, output devices, and communication devices. The central processing unit (CPU) The
central processing unit (CPU) manipulates numbers, letters, and symbols and con- computer hardware element that
controls other elements of a computer
trols the other elements of the computer system. In turn, the CPU consists of two system
units: the arithmetic-logic unit, which performs arithmetic operations (addition, arithmetic-logic unit The part of the
subtraction, multiplication, and division) and comparison operations (for example, CPU that performs arithmetic and logic
7 is greater than 3), and the control unit, which transmits electronic signals to the operations
other components of the computer system to perform needed operations. control unit The part of the CPU that
transmits electronic signals to the other
Computer storage capacity is measured in bytes. In the computer, the number 1
components of a computer system to
represents the presence of an electronic/magnetic signal and the number 0 repre- perform needed operations
sents the absence of the signal. A bit is a binary 0/1 digit representing one of these bit A binary 0 or 1 digit representing the
two mutually exclusive states and is the smallest unit of data in a computer system. presence or absence of an electronic or
A byte is a string of eight bits that the computer stores as a unit. A byte can store a magnetic signal in a computer
number, letter, or symbol. For example, under the ASCII binary coding standard, byte A string of eight bits, representing
a number, letter, or symbol, that the
the letter A is represented by the byte 01000001; each of the eight positions is a bit computer stores as a unit
and each position takes a value equal to either 0 or 1. A kilobyte is a unit of com- kilobyte One thousand bytes
puter storage capacity equal to 1000 bytes (really 1024). A megabyte is equal to megabyte One million bytes
1 million bytes, a gigabyte is equal to 1 billion bytes, and a terabyte is equal to 1 gigabyte One billion bytes
trillion bytes. A petabyte is equal to 1000 terabytes, and an exabyte is equal to terabyte One trillion bytes
1 million terabytes. Five megabytes can hold the text of the entire works of petabyte One thousand terabytes
Shakespeare. Ten terabytes would hold the Library of Congress. Five exabytes would exabyte One million terabytes
hold all the words ever spoken by human beings on this planet.
Primary storage stores the operating system that manages the operation of the primary storage The computer system
computer and all or part of a software program that is being executed, as well as component that stores the operating
system and all or part of a software
the data that are being used by the program. Primary storage includes random
program that is being executed, as well
access memory (RAM), whose contents are lost when the computer is turned off, as the data that are being used by the
and read-only memory (ROM), whose contents are not lost when the computer is program
turned off. Typically, ROM contains software programs burned in by the computer
manufacturer.
Secondary storage is used to store large quantities of data outside the computer secondary storage The computer
and retains its contents when the computer is turned off. The most important tech- system component that stores large
quantities of data outside the computer
nologies for secondary storage are magnetic disks and optical disks.
and retains its contents when the
Magnetic disks can be floppy disks or hard disks. Floppy disks offer convenience computer is turned off
because they are inexpensive and portable, but they typically store only 1 to 3
megabytes and they have a slow access rate. Hard disks offer storage capacities

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