Managing information systems 7th edition brow ch02
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MANAGEMENT INFORMATION SYSTEMS
CHAPTER 2
COMPUTER SYSTEMS
-HARDWARE
-SOFTWARE
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HARDWARE
Chapter 2
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Chapter 2
Chapter 3
Chapter 4
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COMPUTER SYSTEMS
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Hardware:
Physical pieces of a computer system
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Software:
Set of programs that control the operations of a computer
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BASIC COMPONENTS OF COMPUTER SYSTEMS
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All computers made up of the same set of six building
blocks: input, output, memory, arithmetic/logic unit,
control unit, and files
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Control unit and arithmetic/logical unit together known
as the central processing unit (CPU)
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BASIC COMPONENTS OF COMPUTER SYSTEMS
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Input:
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Device(s) needed to enter data into the computer
for it to use in computations and comparisons
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Input: What is the difference between a terminal and a PC?
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Terminal
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Designed strictly for input and output
Has keyboard and screen
Does not have a processor
Connected to a computer with a processor via telecommunications
- Examples: point-of-sale terminal, ATM
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Common Input Methods:
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Keyboard: input entered by user through keystrokes
Mouse, stylus, touchpad: alternative to keystrokes
Disk drive or flash drive: data on disk read into memory
Magnetic ink character recognition (MICR): used to process bank checks
Barcode labeling: scans barcodes on packages or products, and reads into computer
Optical character recognition (OCR): directly scans typed, printed, or handwritten material
Imaging: inputs digital form of documents and photos
Keyboard
Disk Drive
Barcode
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Output:
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Device(s) needed to produce results in a usable
format
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Common Output Methods:
- Video display unit: displays output on a screen
- Disk drive or flash drive: output written to disk for storage
- Printer: output to paper (various types of printers)
- Computer output microfilm (COM): microfilm generated for archive copies in small space
- Voice response units: computer-generated verbal response messages
Video Display
Disk Drive
Microfilm
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Memory:
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Referred to as main memory or primary memory
All data flows to and from memory
Divide into cells
Each has a unique address
Can only store limited amount of data
-Byte: stores one character of data
-Word: stores two or more
characters of data
Memory
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Memory:
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Memory:
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Each memory cell is a set of circuits
Each circuit is on or off (represented by 1 or 0)
Each circuit corresponds to a bit (binary digit)
Most computers – 8 bits (circuits) represents a character (byte)
2 common bit coding schemes used today:
- ASCII
- EBCDIC
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Arithmetic/Logical Unit:
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Carries out:
- Mathematical operations (addition, subtraction,
multiplication, division)
- Logical operations (number comparisons)
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Arithmetic/Logical Unit:
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Consists of VLSI circuits on a silicon chip
Can perform up to billions of operations per second
Numbers are taken from memory as input and results are stored in memory as output
ALU Circuits
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Computer files:
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File devices used to store vast quantities of data
Main memory is limited, volatile and expensive
Advantages:
- File devices or secondary memory are used to store additional
data that is non-volatile
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Disadvantages:
- It has relatively slow speed
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Storage Devices:
Magnetic tape drives, disk drives, floppy drives
Optical CD or DVD drives
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Types of Computer files:
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Sequential Access Files
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Records are stored in sequence according to file’s control key
Usually stored on magnetic tape
Direct Access Files
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Records can be accessed immediately, without regard to physical location
Stored on Direct Access Storage Devices (DASD)
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DIRECT ACCESS STORAGE DEVICES
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Types of DASD:
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Fixed (hard) drives
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Optical disk storage
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- CD-ROM
- DVD-ROM
- CD-R
- DVD-R
- CD-RW
- DVD-RW
Removable drives
- Floppy Drives
- Zip Drives
- Flash (keychain) Drives
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Control unit:
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Controls the other five components of the computer
system
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Used to take advantage of speed and capacity of
other components
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List of operations, called a program, tells the
control unit what to do
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These operations are read from memory,
interpreted, and carried out one at a time (storedprogram concept)
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STORED-PROGRAM CONCEPT
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Computer Program
- A list of what is to be done for an application
- Each step or operation is called an instruction
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Machine Language
- Computer program written for specific computer model
- Program executed by control unit; consists of operation code and addresses
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Measure of Computer Power
- Millions of instructions per second (MIPS)
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- Millions of floating point operations per second (MFLOPS)
Benchmarking is used to compare speed for running a set of jobs on
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different machines
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TYPES OF COMPUTER SYSTEMS
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Table 2.1
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TYPES OF COMPUTER SYSTEMS
Microcomputers:
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For personal computing
Can generally be carried or moved by one person and only have one keyboard and display unit
Examples:
- Desktop PC
- Laptop or notebook
- Handheld or personal digital assistant (PDA)
- Tablet PC
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TYPES OF COMPUTER SYSTEMS
Microcomputers:
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TYPES OF COMPUTER SYSTEMS
Microcomputers, continued:
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Two major microcomputer platforms
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IBM-compatible PCs (personal computers)
Apple microcomputers (does not use Windows OS)
Have been put to a myriad of uses
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Record-keeping
Word processing
Presentations
Programming
and a “client” in a client/server system
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TYPES OF COMPUTER SYSTEMS
Midrange systems:
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In 1980s, included 2 types of computer systems
1. Workstations
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Microcomputers with more powerful chips than PCs
- Reduced instruction set computing (RISC) chip yielded greater performance because it was specialized
2. Minicomputers
- Less powerful and less expensive than mainframe systems
- Used for departmental computers & office automation
Midrange Systems
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