Chapter 4
Information Technology in Business:
Hardware
Objectives
- List a computers major components
- Explain how they interact
- Define each components function
- Understand basic hardware terminology
- List types of peripheral equipment
- Identify different system types
- Define effective computer purchase criteria
- Articulate appropriate hardware evaluation processes
Computer Architecture
All modern computers utilize the same basic architecture.
- Invented/discovered by VonNewmann
All modern computers contain the same
basic components.
Computer Components
- Input/Output Devices
- Central Processing Unit
- Memory
. Internal (L1 or L2 Cache and RAM)
. External
Central Processing Unit
Accepts instructions and data, decodes and executes
the instructions, and stores the results in memory for later display.
Input/Output Devices
Input
- Keyboard
- Scanner
- Voice
- Mouse
Output
Information System Evolution
Mainframes were first used in business
Then, distributed minicomputer systems
Then, stand alone PCs
Now, decentralized PCs, PC based
LANs, as well as mainframe and (Unix) minicomputers all can connect in the Internet.
Information System Trends
- Smaller, Faster, Cheaper
- More connected
- More standardized
- Easier to use
- Emphasis on using information
- Emphasis on empowerment
Digital Computers
Only two internal logic states: on or off.
Must use a binary encoding scheme.
- PCs use ASCII or UNICODE
- IBM mainframes use EBCDIC
Internal Components
A CPU implemented on a single silicon chip is called
a microprocessor.
Consists of two macro components:
- ALU (Arithmetic Logic Unit)
- Control Unit
Moore's Law
The number of discrete components that fit on a chip
doubles every 18 months.
Can't go on forever, but no end in sight.
Several important implications.
Moore's Law Implications
As time goes on computers get:
- More powerful.
- More reliable.
- Cheaper.
- Smaller.
- Require less power.
- More standardized
CPU Terminology
-
Machine Cycle -- One tick of the clock
Hertz -- One cycle per second
Frequency -- Measure of the number of cycles per second.
Word -- Number of bits a control unit fetch in one machine
cycle
Related Terms
- Clock -- Sequences all internal operations.
- Registers -- CPU. s internal storage areas.
- Accumulator -- Special purpose register.
- Instruction register
- Address register
Internal Memory
Related Memory Terms
External Memory -- Slower secondary storage (DASD).
Cache -- Special purpose memory, closely coupled with
the CPU.
L1 and L2 caches operate at different levels
ROM -- Nonvolatile memory that holds the systems BIOS.
Computing Power Issues
Clock Speed
Size, speed, and capacity, of RAM
Word Size
Bus Size and Speed
External Interface Speed
PCI, ISA, AGP
CPU and Cache
Input Devices
Keyboard
Pointing Devices
Touch Screens
Other Input Devices
Source Data Input
Magnetic Ink (MICR) or Strips
Optical mark recognition -- grading tests
Optical bar recognition -- bar codes
Scanners
Graphics
Optical Character Recognition (OCR)
Voice Recognition
Video Output Devices
Monitors
Cathode Ray Tube Technology
Resolution
Refresh Rate
Flat Panel Display
LCD
Active or Passive
Hardcopy Output Devices
Performance issues include speed, color, and resolution
Network compatibility
PCL and Adobe Postscript compatibility
Hardcopy Output Devices
Utilize several different Technologies
Nonimpact
Laser AKA Page Printers
Inkjet
Impact
Dot Matrix
Band
Daisy Wheel
External Storage Media
Punched Cards and Tapes
Magnetic Tapes
Magnetic Disks
Zip
CD-R
Optical Disks
CD
CD-R
CD-RW
DVD
Storage Issues One
Formats
. Sequential
. Random AKA DASD (Direct Access Storage Devices)
Standards
Storage Issues Two
Capacity
Transfer Time
Cost
Computer Classifications
Super (Massively Parallel)
Mainframe
Mini (SMP)
Microcomputers
Laptop or Notebook
PDA
Purchase Considerations
Degree of Institutional Centralization
Support
Institutional Processes
Institutional Needs AKA Problem statement
Principles
