lead black slide. © 2001 business & information systems 2/e2 chapter 4 information system...
TRANSCRIPT
© 2001 Business & Information Systems 2/e
3
Our Agenda Computer Organization Input and Output Devices Primary Storage The Central Processing Unit Secondary Storage
4© 2001 Business & Information Systems 2/e
Learning Objectives Describe the main components of
the computer. List common input and output
devices Describe how is data represented in
a computer? Describe how primary storage is
organized.
5© 2001 Business & Information Systems 2/e
Learning Objectives (cont’d.) Describe the structure and
function of the central processing unit (CPU).
Describe how is data stored and retrieved using common forms of secondary storage?
7© 2001 Business & Information Systems 2/e
What is a computer A computer is a device that is
1. Electronic2. Can store data3. Can store and follow a set of
software instructions, called a program.
8© 2001 Business & Information Systems 2/e
Input Devices An input device accepts data from
outside the computer and converts it into an electronic form the computer can understand.
Examples include a keyboard, mouse, scanner, digital pen, and digital tablet.
9© 2001 Business & Information Systems 2/e
Output Devices An output device converts data
from an electronic form inside the computer to a form that can be used outside the computer.
Examples include a screen, monitor, printer, and fax.
10© 2001 Business & Information Systems 2/e
Primary Storage Primary storage, also called internal
storage, is the “memory”, or RAM, of the computer.
Primary storage, which is temporary storage, is dependent upon continuous electrical power. Any interruption of electrical power causes the contents of primary storage to be lost.
11© 2001 Business & Information Systems 2/e
Central Processing Unit (CPU) The CPU, or processor, carries out
the instructions of the program. It contains circuits that perform arithmetic and logical operations.
Data is transferred from primary storage to the CPU with the results sent back to primary storage.
12© 2001 Business & Information Systems 2/e
Secondary Storage Secondary storage, also called
auxiliary storage, stores data not currently being processed by the computer and represents permanent storage.
Data is usually transferred to and from primary storage.
Examples include hard disks, floppy disks, ZIP disks, CDROMs, and DVDs.
14© 2001 Business & Information Systems 2/e
Keyboards Most widely used input device. Possible physical problems include
Repetitive strain injuries Carpal tunnel syndrome
Ergonomically designed keyboards may improve user comfort and efficiency and reduce risk of injury.
15© 2001 Business & Information Systems 2/e
Pointing Devices Mouse Trackball Trackpoint Trackpad, also called a touchpad Cursor
16© 2001 Business & Information Systems 2/e
Other input devices Touch screen Pen input Graphics tablet Digitizer tablet Light pen
17© 2001 Business & Information Systems 2/e
Optical Scanning Input Devices Bar-code scanner
Universal Product Code (UPC) Flat bed, or page scanner Automatic document feeder (ADF)
scanner Optical Character Recognition (OCR) Mark-sense readers
18© 2001 Business & Information Systems 2/e
Magnetic Scanning Input Devices Magnetic strip reader
Credit cards ID Cards
Magnetic Ink Character Recognition (MICR) – used at the bottom of all checks by the banking industry.
19© 2001 Business & Information Systems 2/e
Voice Input Devices Voice recognition software
Dragon Naturally Speaking Via-Voice
Uses a microphone connected to the computer and translates the spoken word to text output.
20© 2001 Business & Information Systems 2/e
Digital Input Devices Digital cameras that produce
photographic quality images. Cameras connected to the
computer for “live” images.
21© 2001 Business & Information Systems 2/e
Screens, or Monitor, or CRT Key elements of a “screen” include:
Pixels – picture elements arranged as a pattern of dots.
Screen resolution – the number of pixels that can be displayed on a screen at one time.
Refresh rate – the number of times per second that screen “repaints” itself.
22© 2001 Business & Information Systems 2/e
Screens, or Monitor, or CRT (cont’d.) Types of monitors
Traditional “tube” monitors, or cathode ray tube (CRT).
Flat-panel screens – most common type is liquid crystal display (LCD).
Screen projector used to display a computers output on a large screen.
23© 2001 Business & Information Systems 2/e
Printers Printer classifications
Impact printer Nonimpact printer Serial printers Line printers Page printers Letter-quality printers Draft-quality printers
24© 2001 Business & Information Systems 2/e
Desktop printers Ink-jet, or bubble-jet printer
Typically 200 to 300 characters per second
Laser printers Typically between 4 and 24 pages per
minute. Dot matrix printer
Typically between 200 and 300 characters per second.
25© 2001 Business & Information Systems 2/e
High volume printers Line printers
High end line printers can print as much as 3,600 lines per minute (at 60 lines per page, that is 60 page per minute) and can cost $50,000.
Page printers High end page printers can print as
much as 200 pages per minute and can cost $100,000.
26© 2001 Business & Information Systems 2/e
Other Output Devices Plotters Voice output devices – converting
digitized data into synthesized speech Sound output devices – speakers Specialized devices for people with
disabilities – can include large typeface screens, Braille display devices, special pointing devices, or headphones.
27© 2001 Business & Information Systems 2/e
Virtual Reality Virtual reality is the use of a
computer to produce realistic images and sounds in such a way that the user senses that he or she is a part of the scene.
Examples include architectural design, home remodeling, aircraft design, machine design, and more.
29© 2001 Business & Information Systems 2/e
Primary Storage Structure Input data is stored in primary
storage (memory) after it is received from an input device.
Output data is stored in primary storage before it is sent to an output device.
Without sufficient primary storage, it may not be possible to execute certain programs or use certain data.
30© 2001 Business & Information Systems 2/e
Primary Storage Structure (cont’d.) Silicon chips – integrated circuits Volatile storage – dependent upon
continuous power Random Access Memory (RAM)
Non-volatile storage Read-Only Memory (ROM)
31© 2001 Business & Information Systems 2/e
Primary Storage Structure (cont’d.) Binary representation
A combination of positive and negative electrical charges, represented by 1s and 0s when written to represent a character.
One “charge” is called a bit. Eight bits are required to represent a single
character, called a byte. The 256 possible (28) binary
combinations are defined in character set.
32© 2001 Business & Information Systems 2/e
Primary Storage Structure (cont’d.) Personal computer character set
ASCII – American Standard Code for Information Interchange
Mainframe computer character set EBCDIC – Extended Binary Coded Decimal
Interchange Code Though each contains 256 characters,
the definitions are not the same, so a “translator” is required for one machine type to “talk” with the other machine type.
33© 2001 Business & Information Systems 2/e
Primary Storage Structure (cont’d.) Storage locations of the “bytes” are
called allocation units each of which has a unique address.
Storage capacities Kilobyte (KB) or 1024 bytes (210) –
approximately 1,000 bytes, thus the “kilo” Megabyte (MB) or 1,048,756 bytes (220) Gigabyte (GB) or 1,073,741,824 bytes (230) Terabyte (TB) or 1,099,511,627,776 bytes
(240)
© 2001 Business & Information Systems 2/e
34
The Central Processing Unit
Information System Hardware
35© 2001 Business & Information Systems 2/e
Two Main Parts of a CPU Arithmetic-Logic Unit (ALU)
May add, subtract, multiply and divide two numbers. More complex operations are are completed by using sequences of the four basic operations.
Control Unit Analyzes and executes instructions in a
program. Instructions are brought in one at a time from primary storage.
36© 2001 Business & Information Systems 2/e
CPU Speed Early CPUs processed 8 or 16 bits at
a time. Current CPUs process 32 bits, and
some can process 64 or 128 bits at a time.
The “roadway” from primary storage to the CPU is the bus. Higher bus capacities mean faster computers.
37© 2001 Business & Information Systems 2/e
CPU Speed (cont’d.) Clock speed
Measured in megahertz (MHz) or gigahertz (GHz).
One MHz is one million cycles per second. One GHz is one billion cycles per second. Earliest IBM PCs ran at 4.77 MHz. Current PCs run at or above 1,000 MHz
(1 GHz).
38© 2001 Business & Information Systems 2/e
Common CPUs Microcomputer
Intel 4004 Intel 8088 Intel 8086 Intel 80286 Intel 80386 Intel 80486 Intel Pentium Intel Pentium Pro Intel Pentium II Intel Pentium III
Apple/Macintosh Motorola 68000 Motorola 68020 Motorola 68030 Motorola 68040 Motorola Power PC G3
AMD
39© 2001 Business & Information Systems 2/e
Common CPUs (cont’d.) Minicomputer and
Mainframe Developed by the
manufacturer within a “line” of products
HP3000 IBM System/390 DEC Alpha
Supercomputers Generally specific to a
single product
41© 2001 Business & Information Systems 2/e
Types of Secondary Storage Magnetic Disk
Storage Floppy disk Hard disk ZIP disk
Disk organization Disk Head (or side) Track Allocation Unit
42© 2001 Business & Information Systems 2/e
Optical Disk Storage Compact disks (CDROMs)
Capacity of approximately 600MB Writable Compact Disks (CD-RWs)
Capacity of approximately 600MB Digital Video Disks or Digital
Versatile Disks (DVDs) Capacity of approximately 4.7GB to
17GB depending on how it is used.
43© 2001 Business & Information Systems 2/e
Magnetic Tape Storage Magnetic tape has a capacity of
200MB to over 40GB. Data transferred to the tape via a
magnetic tape drive. Data on a tape can only be read
sequentially.
45© 2001 Business & Information Systems 2/e
Key Terms Address Arithmetic-Logic-Unit
(ALU) ASCII Backup Copy Bar-Code Scanner Binary Digit (Bit) Byte CD-R/CD-ROM/CD-RW
Central Processing Unit (CPU)
Chip Compact Disk Computer Control Unit VRT Cursor Disk Pack
46© 2001 Business & Information Systems 2/e
Key Terms (cont’d.) Dot-Matrix Printer Draft-Quality Printer DVD/DVD-ROM EBCDIC Ergonomics Flat Panel Screen Floppy Disk Gigabyte (GB) Gigahertz (GHz)
Hard Disk Impact Printer Input Device Ink-Jet Printer Keyboard Kilobyte (KB) Laser Printer Letter-Quality Printer Line Printer
47© 2001 Business & Information Systems 2/e
Key Terms (cont’d.) Machine Language Magnetic Disk Magnetic Disk Drive Magnetic Ink
Character Recognition (MICR)
Magnetic Strip Reader
Magnetic Tape Magnetic Tape Drive
Massively Parallel Processing
Megabyte (MB) Megahertz (MHz) Microprocessor Microsecond Millisecond Monitor Mouse
48© 2001 Business & Information Systems 2/e
Key Terms (cont’d.) Multifunction Printer Multimedia Multiprocessing Nanosecond Nonimpact Printer Nonvolatile Storage Optical Disk Optical Disk Drive Output Device
Page Printer Parity Bit Pen Input Peripheral Equipment Pixel Plotter Primary (Internal)
Storage Printer
49© 2001 Business & Information Systems 2/e
Key Terms (cont’d.) Processor Program RAID Random Access
Memory (RAM) Random (Direct)
Access Read Only Memory
(ROM) Scanner
Screen Screen Projector Screen Resolution Secondary (Auxiliary)
Storage Sequential Access Serial Printer Storage Location Terabyte (TB)
50© 2001 Business & Information Systems 2/e
Key Terms (cont’d.) Terminal Touch Screen Track Trackball Trackpad Trackpoint Unicode Video Display
Terminal (VDT)
Virtual Reality Volatile Storage
© 2001 Business & Information Systems 2/e
51
Summary Computer Organization Input and Output Devices Primary Storage The Central Processing Unit Secondary Storage