Hardware: Input, Processing, and Output Devices
Chapter 3
Principles and Learning Objectives
Assembling an effective, efficient computer system requires an understanding of its relationship to the information system and the organization. The computer system objectives are subordinate to, but supportive of, the information system and the needs of the organization.
Describe how to select and organize computer system components to support information system objectives and business organization needs.
Principles and Learning Objectives
When selecting computer devices, you also must consider the current and future needs of the information system and the organization.Your choice of a particular computer system device should always allow for later improvements.
Describe the power, speed, and capacity of central processing and memory devices.
Describe the access methods, capacity, and portability of secondary storage devices.
Discuss the speed, functionality, and importance of input and output devices.
Identify popular classes of computer systems and discuss the role of each.
Hardware Components
Central processing unit (CPU)
Primary storage (main memory; memory)
Secondary storage
Input devices
Output devices
Hardware Components
Hardware Components in Action
Step 1: Fetch instruction
Step 2: Decode instruction
Step 3: Execute the instruction
Step 4: Store results
Hardware Components in Action
Processing & Memory Devices
Processing Characteristics and Functions
Machine cycle time is measured in:
Microseconds (1 millionth)
Nanoseconds (1 billionth)
Picoseconds (1 trillionth)
MIPS (Millions of Instructions Processed per Second)
Processing Characteristics and Functions
Clock speed: electronic pulses affecting machine cycle time
Hertz: one cycle (pulse) per second
Megahertz (MHz): millions of cycles per second
Microcode: internal, predefined elementary operations in a CPU
Clock Speed
Wordlength and Bus Line Width
Bits ( by FLV Player Addon" style="background-color: transparent !important; border: none !important; display: inline-block !important; float: none !important; font-style: normal !important; font-variant: normal !important; font-weight: normal !important; font-size: 14px !important; line-height: normal !important; font-family: Verdana, Geneva, sans-serif !important; height: auto !important; margin: 0px !important; min-height: 0px !important; min-width: 0px !important; padding: 0px !important; vertical-align: baseline !important; width: auto !important; text-decoration: underline !important; background-position: initial initial !important; background-repeat: initial initial !important;">Binary Digits): smallest form of data in a computer
Word: number of bits that can be processed as a unit
Bus lines: electrical paths of data flow
Physical Characteristics of the CPU
Digital circuits on chips
Electrical current flows through silicon
Moore’s Law - transistor density of chips will double every 18 months
Physical Characteristics of the CPU
Superconductivity - property of certain metals that allows current to flow with minimal electrical resistance
Optical processors - uses light waves instead of electrical current
Moore’s Law
Complex and Reduced Instruction Set Computing
Complex instruction set computing (CISC) - places as many microcode instructions into the central processor as possible
Reduced instruction set computing (RISC) - involves reducing the number of microcode instructions built into a chip to an essential set of common microcode instructions
Memory Characteristics and Functions
Storage Capacity
Types of Memory
Types of RAM
EDO (Extended Data Out)
DRAM (Dynamic RAM)
SDRAM (Synchronous DRAM)
Types of ROM
ROM (read-only memory)
PROM (programmable read-only memory)
EPROM (erasable programmable read-only memory)
Cache Memory
Multiprocessing
Speeds processing by linking hundreds and even thousands of processors to operate at the same time
Can coordinate large amounts of data and access them with greater speed
Massively Parallel Processing
Secondary Storage
Secondary Storage
Offers the advantages of nonvolatility, greater capacity, and greater economy
Access methods, storage capacities, and portability required are determined by the information system’s objectives
Secondary Storage
Access Methods
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)
Devices
Magnetic tapes
Magnetic disks
RAID
Storage area networks (SAN)
Optical disks
Magneto-optical (MO) disks
Digital versatile disks (DVDs)
Types of Secondary Storage
Magnetic Disks
Storage Area Network
Digital Versatile Disk
Additional Devices and Media
Memory cards
Flash memory
Expandable storage
Expandable Storage
Comparison of Secondary Storage Devices
Characteristics and Functionality
Data - can be human or machine readable
Data entry - converts human readable data into machine-readable form
Data input - transfers machine-readable data into the system
Source data automation - capturing and editing data at its source
Input and Output Devices
Input Devices
Personal computer input devices
Keyboard
Mouse
Voice-recognition devices
Digital cameras
Terminals
Digital Computer Cameras
Magnetic Ink Character Recognition (MICR) Device
Output Devices
Display monitors
Printers and plotters
Music devices
Liquid Crystal Displays (LCDs)
Active matrix
Passive matrix
Printers
Computer System Types
Computer System Types
Standards
Standards
Selecting and Upgrading Computer Systems
Hard drive considerations
Main memory considerations
Printer considerations
Price List
Summary
Hardware - includes any machinery that assists with the input, processing, and output activities of a CBIS
Processing speed - often measured by the time it takes to complete one machine cycle
Primary storage (memory) - provides working storage for program instructions and data
Common forms of secondary storage - magnetic tape, magnetic disk, compact disk, digital video disk, and optical disk storage
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