1. Hardware: Input, Processing, and Output Devices
Chapter 3
Hardware:
Input, Processing, and Output Devices

2. Computer System
Special subsystem of an organization's overall information system
Integrated assembly of physical devices, centered around at least one processing mechanism utilizing digital electronics
Used to input, process, store, and output data and information

3. Computer System Components
[Figure 3.1]
Computer system hardware components include devices that perform the functions of input, processing, data storage, and output.

4. Central Processing Unit (CPU)
Arithmetic/logic unit (ALU)
Performs mathematical calculations
Makes logical comparisons
Control unit
Sequentially accesses and decodes program instructions
Coordinates flow of data in and out of the ALU, registers, primary storage, secondary storage, output devices
Registers
High-speed storage areas
Temporarily hold small units of program instructions and data immediately before, during, and after execution by CPU

5. Primary Storage
Holds program instructions and data immediately before or immediately after the registers
Also called memory or main memory
Closely associated with the CPU

6. Execution of an Instruction
Instruction phase
Step 1: Fetch instruction
Step 2: Decode instruction
Instruction time (I-time): The time to complete the instruction phase

7. Execution of an Instruction
Execution phase
Step 3: Execute instruction
Step 4: Store results
Execution time (E-time): The time to complete the execution phase

8. Execution of an Instruction
Fig 3.2

9. CPU Characteristics Machine cycle time Clock speed
Wordlength and bus line width
Physical characteristics
Complex and reduced instruction set computing

10. Machine Cycle Time Measured in fractions of a second
Millisecond - one thousandth of one second
Microsecond - one millionth of one second
Nanosecond - one billionth of one second
Picosecond - one trillionth of one second
Or in terms of instructions per second
MIPS - millions of instructions per second

11. Clock Speed
Predetermined rate at which the CPU produces a series of electronic pulses
Microcode
Predetermined internal instructions executed in accordance with clock speed
Often measured in megahertz (MHz) or millions of cycles per second; ranges from 20 MHz to over 200 MHz for PCs

12. Clock Speed and the Execution of Microcode Instructions
[Figure 3.3]

13. Wordlength and Bus Line Width
Bit
A binary digit: 0 or 1
Wordlength
Number of bits the CPU can process at any one time
Bus lines
Physical wiring that connects computer system components

14. Physical Characteristics of the CPU
Moore’s Law: The hypothesis that transistor densities on a single chip will double every 18 months
[Figure 3.4]

15. CISC and RISC Complex instruction set computing (CISC)
Places as many microcode instructions into the central processor as possible
Reduced instruction set computing (RISC)
Reduces the number of microcode instructions built into a chip to an essential set of common instructions

16. Memory Storage capacity Types of memory Byte = eight bits
Kilo, Mega, Giga, Tera
Types of memory
Random access memory (RAM)
Temporary and volatile
Read-only memory (ROM)
Permanent and non-volatile
Cache memory
High-speed, quicker access than main memory

17. Basic Types of Memory Chips

18. Cache Memory

19. Multiprocessing
Processing that occurs using more than one processing unit
Coprocessor
A processor that speeds processing by executing specific types of instructions while the CPU works on another processing activity

20. Parallel Processing
Speeds processing by linking several processors to operate at the same time

21. Parallel Processing Shared memory processing (SMP)
Involves fewer processors and a common pool of main memory
An independent task runs on each processor
Massively parallel processing (MPP)
Involves hundreds or thousands of microprocessor chips assigned to do the computing for a single program

22. Parallel Processing
[Figure 3.8]

23. Secondary Storage
The portion of the computer that holds large amounts of data, instructions, and information more permanently than does main memory
Also called permanent storage

24. Cost Comparison of Various Forms of Data Storage
[Figure 3.9]

25. Access Method Trade-Offs
Direct access
Process by which data and information are retrieved directly, without the need to pass by other data in sequence
Sequential access storage device (SASD)
Device used to sequentially access secondary storage media

26. Access Method Trade-Offs
Direct access storage device (DASD)
Device used to directly access secondary storage media

27. Secondary Storage Devices
Magnetic tape
Common secondary storage media
Mylar film coated with iron oxide
Magnetic disks
Steel platters (hard disks) or Mylar film (floppy disks) coated with iron oxide
Fig. 3.11

28. Secondary Storage Devices
Redundant array of independent/ inexpensive disks (RAID)
Generates extra bits of data from existing data so the system can create a “reconstruction map” to rebuild lost data
Disk mirroring
Provides an exact copy of data on drive

29. Secondary Storage Devices
Optical disks
A rigid disk of plastic onto which data is recorded by special lasers that physically burn pits into the disk
Compact disk read-only memory (CD-ROM)
A common form of optical disk on which data, once recorded, cannot be modified

30. Secondary Storage Devices
CD-rewriteable (CD-R)
Allows PC users to replace their diskettes with high capacity CDs that can be written upon and edited over
Write-once, read-many (WORM)
Allows businesses to record customized data and information onto an optical disk

31. Secondary Storage Devices
Magneto-optical disk
A hybrid between magnetic disks and optical disks
Digital video disk (DVD)
Looks like a CD-ROM disk, but can store about 135 minutes of digital video
Fig. 3.12

32. Secondary Storage Devices
Memory cards
Credit-card sized devices that can be installed in an adapter or slot in many personal computers
Flash memory
A silicon chip that is nonvolatile and keeps its memory when the power is shut off

33. Secondary Storage Devices
Expandable storage
Storage devices that use removable disk cartridges
Fig. 3.13

34. Secondary Storage Devices
Floptical disk
Experimental storage device that is the same size as a diskette, but is able to hold many more times the data

35. Comparison of Secondary Storage Devices
[Table 3.2]

36. Speed And Functionality
The nature of data
Human-readable data vs. machine-readable data
Data entry and input
Data entry: Human-readable data is converted into a machine-readable
Data input: Machine-readable data is transferred into the system
continued...

37. Speed And Functionality
Source data automation
Automation of data entry and input where the data is created, thus ensuring accuracy and timeliness

38. Input Devices Personal computer input devices
Keyboard
Mouse
Voice recognition devices
Digital computer cameras
Terminals
Scanning devices
Optical data readers
Optical mark recognition readers
Optical character reader
continued...

39. Input Devices Magnetic ink character recognition (MICR) devices
Point-of-sale (POS) devices
Automatic teller machine (ATM) devices
Pen input devices
Light pens
Touch-sensitive screens
Bar code scanners

40. Sample Input Device: Digital Computer Camera
Fig. 3.14

41. Sample Input Device: MICR Device
Fig. 3.15

42. Output Devices: Monitors
Display monitors
Monochrome
RGB (red, green, blue)
Color graphics adapter (CGA)
Enhanced graphics adapter (EGA)
Video graphics array (VGA)
Extended graphics array (XGA)
Liquid crystal display (LCDs)

43. Output Devices: Printers, Plotters, and Microfilm
Impact printers
Letter-quality printers, dot-matrix printers, near-letter quality printers (NLQ)
Non-impact printers
Ink-jet printers and laser printers
Plotters
Computer output microfilm devices (COM)
Special-Purpose Devices: Multifunction device
A device that combines several input/output devices (e.g., printer, fax, scanner)

44. Classifying Computers
Special-purpose computers
Used for limited applications
General-purpose computers
Most common type of computers
Used for a variety of applications

45. Types of Computer Systems
Personal computers
Network computers
Workstations
Midrange computers
Mainframes
Supercomputers

46. Types of Computer Systems
Personal computers
Relatively small and inexpensive
Also called microcomputers

47. Computer System Types Network Computers Workstations
Stripped-down personal computers
Primarily used with network system and the Internet
Workstations
Fit between high-end microcomputers and low-end midrange computers in terms of cost and processing power

48. Computer System Types Midrange computers Mainframes Supercomputers
Systems that can accommodate several users at one time
Formerly known as minicomputers
Mainframes
Large powerful computers often shared by hundreds of concurrent users connected to the machine via terminals
Supercomputers
Most powerful computer systems with the fastest processing speeds

49. Network Computer Processor speed Amount of RAM Approximate cost
1-5 MIPs
Amount of RAM
4-16 MB
Approximate cost
$500-$1,500
How used
Supports data entry
Connects to the Internet
Example
Oracle Network computer

50. Personal Computer Processor speed Amount of RAM Approximate cost
5-20 MIPs
Amount of RAM MB
Approximate cost
$1,200-$5,000
How used
Improves individual worker’s productivity
Example
Compaq Pentium computer

51. Workstation Processor speed Amount of RAM Approximate cost How used
MIPs
Amount of RAM MB
Approximate cost
$4,000 to over $20,000
How used
Engineering CAD
Software development
Example
Sun Microsystems computer

52. Midrange Computer Processor speed Amount of RAM Approximate cost
MIPs
Amount of RAM MB
Approximate cost
$20,00 to over $100,000
How used
Meets computing needs for a department or small company
Example
Hewlett-Packard HP-9000

53. Mainframe Computer Processor speed Amount of RAM Approximate cost
40-4,550 MIPs
Amount of RAM
256-1,024 MB
Approximate cost
$250,000 to over $2 million
How used
Meets computing needs for a company
Example
IBM ES/9000

54. Supercomputer Processor speed Amount of RAM Approximate cost How used
60 billion-3 trillion instructions per sec
Amount of RAM
8,192MB+
Approximate cost
$2.5 million- $3.5 million
How used
Scientific applications
Marketing
Customer support
Product development
Example
Cray C90

55. Multimedia Computers
Involves the marriage of sound, animation, and digitized video
Multimedia standards
Enable software and hardware vendors to build products that will work together to meet the needs of their customers

56. Multimedia Support Microsoft multimedia extension for Windows
Multimedia PC Council (MPC)
IBM Ultimedia Solution

57. Multimedia Support: Audio
Musical Instrument Digital Interface (MIDI)
Standard system for connecting musical instruments and synthesizers to computers
Digital signal processor (DSP)
A chip used by advanced sound systems to improved the analog-to-digital-to-analog conversion process

58. Multimedia Support: Video
Video compression
A process that uses mathematical formulas to reduce the number of bits required to present a single video frame

59. Hardware Components of Multimedia Computer System
[Figure 3.18]

60. Architecture and Upgrades: Responding to Change
Computer system architecture
The structure, or configuration, of hardware components of a computer system

61. Computer Standards
Approved reference models determined by groups for building various products
Common PC standards:
Plug and play (PnP)
Small Computer Systems Interface (SCSI)
Multimedia extension (MMX)

62. Information Systems Principles
Assembling an efficient computer subsystem 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 organization.

63. Information Systems Principles
Components of information systems (input devices, people, procedures, goals) are interdependent. Because the performance of one system affects the others, all systems should be measured according to the same standards of effectiveness and efficiency.

64. Information Systems Principles
When selecting computer subsystem devices, consider current and future needs. The choice of a particular computer system should allow for later improvements in the overall information system. Reasoned forethought is the hallmark of a true systems professional.

65. Information Systems Principles
Determine hardware needs based on how the hardware will be used to support the objectives of the information systems and the goals of the organization. For PC users, this means knowing what software you want to run.

66. Information Systems Principles
Do research to gain an understanding of the trade-offs between overall system performance, and cost, control, and complexity.