1. Principles of Information Systems Eighth Edition
Chapter 3
Hardware: Input, Processing, and Output Devices

2. Principles and Learning Objectives
Assembling an effective, efficient set of computer hardware devices requires understanding their role in supporting the underlying information systems and the needs of the organization; the computer hardware objectives are subordinate to, but supportive of, the information systems and the needs of the organization
Describe how to select and organize computer hardware components to support information system (IS) objectives and business needs
Principles of Information Systems, Eighth Edition

3. Principles and Learning Objectives (continued)
When selecting computer hardware, you must consider the current and future needs of the information systems and the organization; your choice of a hardware device should always allow for later improvements to meet evolving organizational needs
Describe the power, speed, and capacity of central processing and memory devices
Describe the access methods, capacity, and portability of secondary storage devices
Principles of Information Systems, Eighth Edition

4. Principles and Learning Objectives (continued)
Discuss the speed, functionality, and importance of input and output devices
Identify popular classes of computer systems and discuss the role of each
Principles of Information Systems, Eighth Edition

5. Why Learn About Hardware?
Can improve productivity, increase revenue, reduce costs, and provide better service
Managers are expected to know about hardware
To help define business needs
To ask questions and evaluate options when buying equipment
Principles of Information Systems, Eighth Edition

6. Introduction
Hardware: any machinery (most of which use digital circuits) that assists in the input, processing, storage, and output activities of an information system
When making hardware decisions, businesses must consider how the hardware can support:
Objectives of the information system
Goals of the organization
Principles of Information Systems, Eighth Edition

7. Computer Systems: Integrating The Power of Technology
Choosing the right computer hardware requires understanding its relationship to the information system and needs of the organization
Hardware objectives are subordinate to, but supportive of, the information system and the current and future needs of the organization
Principles of Information Systems, Eighth Edition

8. Hardware Components Central processing unit (CPU) Input devices
Output devices
Principles of Information Systems, Eighth Edition

9. Hardware Components (continued)
Communications devices
Primary storage devices
Secondary storage devices
Principles of Information Systems, Eighth Edition

10. Hardware Components (continued)
Figure 3.1: Hardware Components
Principles of Information Systems, Eighth Edition

11. Central processing unit (CPU)
The part of the computer that consists of three associated elements: the arithmetic/logic unit, the control unit, and the register areas.
arithmetic/logic unit (ALU) : The part of the CPU that performs mathematical calculations and makes logical comparisons.
Principles of Information Systems, Eighth Edition

12. Central processing unit (CPU)
control unit: The part of the CPU that sequentially accesses program instructions, decodes them, and coordinates the flow of data in and out of the ALU, Registers, primary storage, and even secondary storage and various output devices.
Principles of Information Systems, Eighth Edition 12 12

13. Central processing unit (CPU)
Register: A high-speed storage area in the CPU used to temporarily hold small units of program instructions and data immediately before, during, and after execution by the CPU.
primary storage (main memory; memory): The part of the computer that holds program instructions and data.
Principles of Information Systems, Eighth Edition

14. Hardware Components in Action
Step 1: Fetch instruction
Step 2: Decode instruction
Step 3: Execute instruction
Step 4: Store results
Principles of Information Systems, Eighth Edition

15. Hardware Components in Action
Step 1: Fetch instruction. The computer reads the next program instruction to be executed and any necessary data into the processor.
Step 2: Decode instruction. The instruction is decoded and passed to the appropriate processor execution unit.
Principles of Information Systems, Eighth Edition

16. Hardware Components in Action
Each execution unit plays a different role:
The arithmetic/logic unit performs all arithmetic operations,
the floating-point unit deals with noninteger operations
Principles of Information Systems, Eighth Edition

17. Hardware Components in Action
the load/store unit manages the instructions that read or write to memory,
etc.
The time it takes to perform the instruction phase (Steps 1 and 2) is called the instruction time
(I-time).
Principles of Information Systems, Eighth Edition 17 17

18. Hardware Components in Action
Step 3: Execute instruction. The hardware element, now freshly fed with an instruction and data, carries out the instruction. This could involve making an arithmetic computation, logical comparison, bit shift, or vector operation.
Principles of Information Systems, Eighth Edition

19. Hardware Components in Action
Step 4: Store results. The results are stored in registers or memory.
The time it takes to complete the execution phase (Steps 3 and 4) is called the execution time
(E-time).
Principles of Information Systems, Eighth Edition 19 19

20. Hardware Components in Action
After both phases have been completed for one instruction, they are performed again for the second instruction, and so on.
Completing the instruction phase followed by the exe­cution phase is called a machine cycle. Some processing units can speed processing by using pipelining, whereby the processing unit gets one instruction, decodes another, and executes a third at the same time.
Principles of Information Systems, Eighth Edition

21. Hardware Components in Action (continued)
Figure 3.2: Execution of an Instruction
Principles of Information Systems, Eighth Edition

22. Processing and Memory Devices: Power, Speed, and Capacity
System unit
Houses the components responsible for processing (the CPU and memory)
All other computer system devices are linked either directly or indirectly into the system unit housing
Principles of Information Systems, Eighth Edition

23. Processing Characteristics and Functions
Machine cycle time is measured in:
Nanoseconds (1 billionth of a second)
Picoseconds (1 trillionth of a second)
MIPS (millions of instructions per second)
Principles of Information Systems, Eighth Edition

24. Processing Characteristics and Functions (continued)
Clock speed: series of electronic pulses produced at a predetermined rate that affects machine cycle time
Often measured in:
Megahertz (MHz): millions of cycles per second
Gigahertz (GHz): billions of cycles per second
Microcode: predefined, elementary circuits and logical operations that the processor performs when it executes an instruction
Principles of Information Systems, Eighth Edition

25. Processing Characteristics and Functions (continued)
The control unit executes the microcode in accordance with the electronic cycle, or pulses of the CPU "clock." Each microcode instruction takes at least the same amount of time as the interval between pulses. The shorter the interval between pulses, the faster each microcode instruction can be executed.
Accordance:انسجام
Principles of Information Systems, Eighth Edition

26. Processing Characteristics and Functions (continued)
Because the number of microcode instructions needed to execute a single program instruction-such as performing a calculation or printing results-can vary, the clock speed is not directly related to the true processing speed of the computer.
Principles of Information Systems, Eighth Edition

27. Processing Characteristics and Functions (continued)
As the clock speed of the CPU increases, additional heat is generated that can corrupt the data and instructions the computer is trying to process. Because this can lead to errors that cause a program to behave erratically, chip and computer manufacturers must be wary of potential heat problems in their new designs.
Principles of Information Systems, Eighth Edition 27 27

28. Physical Characteristics of the CPU
Most CPUs are collections of digital circuits imprinted on silicon wafers, or chips, each no bigger than the tip of a pencil eraser.
To turn a digital circuit on or off within the CPU, electrical current must flow through a medium (usually silicon) from point A to point B.
The speed the current travels between points can be increased by either reducing the distance between the points or reducing the resistance of the medium to the electrical current.
Principles of Information Systems, Eighth Edition

29. 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
Principles of Information Systems, Eighth Edition 29 29

30. Physical Characteristics of the CPU (continued)
Figure 3.3: Moore’s Law
Principles of Information Systems, Eighth Edition

31. Memory Characteristics and Functions
Main memory
Located physically close to the CPU, but not on the CPU chip itself
Rapidly provides data and instructions to the CPU
Principles of Information Systems, Eighth Edition

32. Table 3.1: Computer Storage Units
Storage Capacity
Table 3.1: Computer Storage Units
Principles of Information Systems, Eighth Edition

33. Types of Memory Random access memory (RAM) Types of RAM
Temporary and volatile
Types of RAM
EDO (Extended Data Out)
DRAM (Dynamic RAM)
SDRAM (Synchronous DRAM)
Principles of Information Systems, Eighth Edition

34. Types of Memory (continued)
Types of nonvolatile memory
ROM (read-only memory)
PROM (programmable read-only memory)
EPROM (erasable programmable read-only memory)
Cache memory: high-speed memory that a processor can access more rapidly than main memory
Principles of Information Systems, Eighth Edition

35. Types of Memory (continued)
Figure 3.4: Basic Types of Memory Chips
Principles of Information Systems, Eighth Edition

36. Types of Memory (continued)
Figure 3.5: Cache Memory
Principles of Information Systems, Eighth Edition

37. Types of Memory (continued)
Because cache memory holds less data, the CPU can access the desired data and instructions more quickly than selecting from the larger set in main memory. Thus, the CPU can execute instructions faster, improving the overall performance of the computer system.
Principles of Information Systems, Eighth Edition 37

38. Types of Memory (continued)
There are three types of cache memory.
The Level 1 (LI) cache is on the CPU chip.
The Level 2 (L2) cache memory can be accessed by the CPU over a high-speed dedicated interface. The latest processors go a step further and place the L2 cache directly on the CPU chip itself and provide high-speed support for a tertiary Level 3 (L3) external cache. Deerfield, the low-power version of Intel's 64-bit servers called the Itanium 2 chip, was introduced with 1.5 MB of Level 3 cache.
Dedicated: محجوز لاستعمال معين
Principles of Information Systems, Eighth Edition 38

39. Types of Memory (continued)
When the processor needs to execute an instruction, the instruction's operation code indicates whether the data will be in a register or in memory. If the operation code specifies a register as the source, it is taken from there. Otherwise, the processor looks for the data in the LI cache, then the L2 cache, and then the L3 cache. If the data is not in any cache, the CPU requests the data from main memory. If the data is not even stored in main memory, the system has to retrieve the data from secondary storage.
Dedicated: محجوز لاستعمال معين
Principles of Information Systems, Eighth Edition 39

40. Types of Memory (continued)
It can take from one to three clock cycles to fetch information from the LI cache, while the CPU waits and does nothing. It takes 6 to 12 cycles to get data from an L2 cache on the processor chip. It can take dozens of cycles to fetch data from an L3 cache and hundreds of cycles to fetch data from secondary storage.
Because this hierarchical arrangement of memory helps the CPU find data faster, it bridges a widening gap between processor speeds
Dedicated: محجوز لاستعمال معين
Principles of Information Systems, Eighth Edition 40

41. Multiprocessing
Multiprocessing: simultaneous execution of two or more instructions at the same time
Multiprocessing using coprocessors
Coprocessor: speeds processing by executing specific types of instructions while the CPU works on another processing activity
Principles of Information Systems, Eighth Edition

42. Multiprocessing
Coprocessors can be internal or external to the CPU and can have different clock speeds than the CPU. Each type of coprocessor performs a specific function.
A multicore microprocessor combines two or more independent processors into a single computer so that they can share the workload and boost processing capacity. a dual-core processor enables people to perform multiple tasks simultaneously .
Principles of Information Systems, Eighth Edition 42 42

43. Parallel Computing
Parallel computing: simultaneous execution of the same task on multiple processors to obtain results faster
Massively parallel processing:
Speeds processing by linking hundreds or thousands of processors to operate at the same time, or in parallel
Each processor has its own bus, memory, disks, copy of the operating system, and applications
Principles of Information Systems, Eighth Edition

44. Parallel Computing (continued)
Different approaches to achieving parallel computing
Single instruction/multiple data (SIMD) parallel processors
Multiple instruction/multiple data (MIMD) parallel processors
Grid computing: use of a collection of computers, often owned by multiple individuals or organizations, to work in a coordinated manner to solve a common problem
Principles of Information Systems, Eighth Edition

45. Parallel Computing (continued)
The most frequent business uses for parallel computing include:
modeling.
simulating.
analyzing large amounts of data
Principles of Information Systems, Eighth Edition 45 45

46. Secondary Storage
Compared with memory, 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
Principles of Information Systems, Eighth Edition

47. Access Methods Sequential access: records must be retrieved in order
Devices used are called sequential access storage devices (SASDs)
Direct access: records can be retrieved in any order
Devices used are called direct access storage devices (DASDs)
Principles of Information Systems, Eighth Edition

48. Devices Magnetic tapes Magnetic disks RAID Virtual tape Optical disks
Principles of Information Systems, Eighth Edition

49. Devices (continued) Digital video disk (DVD)
Holographic Versatile Disc (HVD)
Memory cards
Flash memory
Principles of Information Systems, Eighth Edition

50. Enterprise Storage Options
Attached storage
Network-attached storage (NAS)
Storage area network (SAN)
Principles of Information Systems, Eighth Edition

51. Enterprise Storage Options (continued)
Figure 3.9: Storage Area Network
Principles of Information Systems, Eighth Edition

52. Input and Output Devices: The Gateway to Computer Systems
Through input and output devices, people provide data and instructions to the computer and receive results from it
Selection of input and output devices depends on organizational goals and IS objectives
Principles of Information Systems, Eighth Edition

53. Characteristics and Functionality
Data can be human-readable or machine-readable
Data entry: converts human-readable data into machine-readable form
Data input: transfers machine-readable data into system
Source data automation: capturing and editing data where the data is initially created and in a form that can be directly input to a computer
Principles of Information Systems, Eighth Edition

54. Input Devices Personal computer input devices
Keyboard
Mouse
Speech-recognition technology
Digital cameras
Terminals
Principles of Information Systems, Eighth Edition

55. Input Devices (continued)
Scanning devices
Optical data readers
Magnetic ink character recognition (MICR) devices
Magnetic stripe card
Point-of-sale (POS) devices
Principles of Information Systems, Eighth Edition

56. Input Devices (continued)
Automated teller machine (ATM) devices
Pen input devices
Touch-sensitive screens
Bar-code scanners
Radio Frequency Identification (RFID)
Principles of Information Systems, Eighth Edition

57. Output Devices Display monitors Liquid crystal displays (LCDs)
Organic light-emitting diodes (OLEDs)
Printers and plotters
Digital audio player
Principles of Information Systems, Eighth Edition

58. Special-Purpose Input and Output Devices
Computer-based navigation systems
Multiple function printers
Eyebud screens
Principles of Information Systems, Eighth Edition

59. Computer System Types, Selection, and Upgrading
Special-purpose computers: used for limited applications by military and scientific research groups
General-purpose computers: used for a wide variety of applications
Principles of Information Systems, Eighth Edition

60. Computer System Types Handheld computers Portable computers
Thin client
Desktop computers
Principles of Information Systems, Eighth Edition

61. Computer System Types (continued)
Workstations
Servers
Mainframe computers
Supercomputers
Principles of Information Systems, Eighth Edition

62. Selecting and Upgrading Computer Systems
Dispose of old equipment properly
Consider factors such as speed, cost, and performance when upgrading
Hard drive
Main memory
Printer
DVD burners
Principles of Information Systems, Eighth Edition

63. Summary
Hardware: machinery that assists in the input, processing, storage, and output activities of an information system
Hardware components: central processing unit (CPU), input and output devices, communications devices, primary storage devices, and secondary storage devices
Random access memory (RAM): temporary and volatile
ROM (read-only memory): nonvolatile
Principles of Information Systems, Eighth Edition

64. Summary (continued)
Multiprocessing: simultaneous execution of two or more instructions at the same time
Sequential access: records must be retrieved in order
Direct access: records can be retrieved in any order
Examples of secondary storage devices: magnetic tapes and disks, DVDs, memory cards, etc.
Enterprise storage options: attached storage, network-attached storage (NAS), and storage area network (SAN)
Principles of Information Systems, Eighth Edition

65. Summary (continued)
Examples of input devices: keyboards, mice, voice-recognition devices, terminals, scanning devices, and touch-sensitive screens
Examples of output devices: display monitors, liquid crystal displays (LCDs), printers, and plotters
Computers can be classified as either special-purpose or general-purpose
Computer system types: handheld computers, portable computers, desktop computers, workstations, servers, etc.
Principles of Information Systems, Eighth Edition