Chapter 03 - Computer Hardware
3 Computer Hardware
Chapter 3: Computer Hardware reviews history, trends, and developments in microcomputer, midrange, and
CHAPTER
mainframe computer systems; basic computer OVERVIEW
system concepts; and the major types of technologies used in
peripheral devices for computer input, output, and storage.
LEARNING
After reading and studying this chapter, OBJECTIVES
you should be able to:
1. Understand the history and evolution of computer hardware.
2. Identify the major types and uses of microcomputer, midrange, and mainframe computer systems.
3. Outline the major technologies and uses of computer peripherals for input, output, and storage.
4. Identify and give examples of the components and functions of a computer system.
5. Identify the computer systems and peripherals you would acquire or recommend for a business of your
choice, and explain the reasons for your selections.
• Computer Systems. Major types of computer systems are summarized in Figure 3.3 . Microcomputers are used
as personal computers, network computers, personalSUMMARY
digital assistants, technical workstations, and information
appliances. Midrange systems are increasingly used as powerful network servers and for many multiuser business
data processing and scientific applications. Mainframe computers are larger and more powerful than most midsize
systems. They are usually faster, have more memory capacity, and can support more network users and peripheral
devices. They are designed to handle the information processing needs of large organizations with high volumes of
transaction processing or with complex computational problems. Supercomputers are a special category of
extremely powerful mainframe computer systems designed for massive computational assignments.
• The Computer Systems Concept. A computer is a system of information processing components that perform
input, processing, output, storage, and control functions. Its hardware components include input and output
devices, a central processing unit (CPU), and primary and secondary storage devices. The major functions and
hardware in a computer system are summarized in Figure 3.10 .
• Peripheral Devices. Refer to Figures 3.14 and 3.22 to review the capabilities of peripheral devices for
input, output, and storage discussed in this chapter.
3-
,Chapter 03 - Computer Hardware
KEY TERMS AND CONCEPTS
1. Binary representation (108):
The presence or absence of electronic, magnetic, or optic “signals” in the computer’s circuitry or in the media it
uses. There are only two possible states or conditions - presence or absence. These may also be interpreted as
on/off, or 0/1.
2. Central processing unit (93):
The component of a computer system that includes the circuits controlling the interpretation and execution of
instructions. The CPU includes the arithmetic-logic unit and the control unit.
3. Computer system (92):
A computer system consists of input and output devices, primary and secondary storage devices, the central
processing unit, and other peripheral devices.
4. Computer terminal (85):
A terminal is any device that enables both input and output between a user and a computer via
telecommunications link.
5. Cycles per second (94):
Denoted as Hz, cycles per second is a measure of the speed of the computer's timing circuits or internal clock.
The higher the number, the faster the CPU. Cycles in the millions per second range are called megahertz
(MHz), in the billions per second range are called gigahertz (GHz), and in the trillions per second range are
called terahertz (THz).
6. Direct access (109):
A method of storage where each storage cluster has a unique address and can be individually accessed in
approximately the same period of time as any other cluster without having to first search through preceding
sectors. Instructor's note: these storage positions are not necessarily individual bits of memory. On disk-
based media, an individual memory location is called a "cluster". Clusters may vary in size between disk
partitions but will remain uniform in capacity within a partition. Cluster size can only be set during partition
formatting.
7. Graphical user interface (97):
A design approach that enables users to interact with a computer by manipulating images or "icons" that
represent objects or actions.
8. Information appliance (86):
Hand-held microcomputer devices. Most of these devices now include wireless connectivity to the Internet and
innovative I/O methods such as touch screens, pen-based handwriting recognition, and detachable keypads.
9. Magnetic disks (112):
Data storage technology that uses magnetised spots on metal or plastic disks.
a. Floppy disk (112):
Small, flexible, plastic disk enclosed in a protective envelope and hard plastic shell. It holds data in the
form of magnetised spots. These were once widely used to provide a removable direct access storage
capability for microcomputer systems.
3-
, Chapter 03 - Computer Hardware
b. Hard disk (113):
A secondary storage medium consisting of metal disks covered with a magnetic recording surface. It
holds data in the form of magnetised spots. Microcomputers typically have at least one built in hard drive.
They may also have the capacity to add additional internal and/or external drives. Single drive storage
capacity ranges up to 1.5 TB and continues to increase.
c. RAID (Redundant array of independent disks ) (113):
A RAID array comprises two or more interconnected microcomputer hard disk drives and their controllers.
They provide, fault tolerant storage capacities. RAID arrays are characterized by their ability to continue
running without data loss even if one drive should fail.
10. Magnetic stripe (105):
A strip of magnetic tape embedded in a plastic card and widely used for credit/debit cards and identification
cards. These stripes hold up to 200 bytes of information.
11. Magnetic tape (113):
A plastic tape with a magnetic surface on which data can be stored by selective magnetisation of portions of
the surface. Tapes can only be read sequentially from beginning to end. As a result, magnetic tapes are
primarily used for data archiving and data backups.
12. Mainframe system (89):
This category comprises large, fast, and powerful computer systems. Processing speeds range up to billions of
instructions per second. Primary memory may consist of hundreds or thousands of gigabytes. Usage
considerations include cost, space, air-conditioning, and uninterrupted power supplies. They are used for
computationally tense applications such as managing airline reservation systems or financial transactions in
banking institutions.
13. Microcomputer (83):
Also called a "Personal Computer" or "PC", these are small computers, ranging in size from a “computer on a
chip” to a small typewriter-size unit. These networked workstations are critical to individuals and business
professionals.
14. Midrange system (87):
Larger, more powerful, and more expensive than most microcomputers but are smaller, less powerful, and less
expensive than most large mainframe computer systems, these computers are used to handle large-scale
processing for integrated enterprise wide manufacturing, distribution, and financial applications, large websites,
or data warehouse management and related data mining and online analytical processing (OLAP) applications.
15. Minicomputer (88):
This category comprises mid-range computer that might be used as a high-end workstation for computationally
intense applications. They are often found in industrial process control systems such as computer aided
manufacturing (CAM) applications. These computers may also serve as front-end servers to relieve mainframe
computers of telecommunications and network management tasks. While microcomputers would fit on, under,
or next to a desk, minicomputers are larger and are generally not co-located with its users.
16. MIPS (94):
An acronym standing for Millions of Instructions per Second. This is a way of measuring relative CPU speed
(see also cycles per second – measured in MHz)
17. Moore's law (94):
Moore predicted that the number of transistors per integrated circuit will double every 18 to 24 months.
3-
3 Computer Hardware
Chapter 3: Computer Hardware reviews history, trends, and developments in microcomputer, midrange, and
CHAPTER
mainframe computer systems; basic computer OVERVIEW
system concepts; and the major types of technologies used in
peripheral devices for computer input, output, and storage.
LEARNING
After reading and studying this chapter, OBJECTIVES
you should be able to:
1. Understand the history and evolution of computer hardware.
2. Identify the major types and uses of microcomputer, midrange, and mainframe computer systems.
3. Outline the major technologies and uses of computer peripherals for input, output, and storage.
4. Identify and give examples of the components and functions of a computer system.
5. Identify the computer systems and peripherals you would acquire or recommend for a business of your
choice, and explain the reasons for your selections.
• Computer Systems. Major types of computer systems are summarized in Figure 3.3 . Microcomputers are used
as personal computers, network computers, personalSUMMARY
digital assistants, technical workstations, and information
appliances. Midrange systems are increasingly used as powerful network servers and for many multiuser business
data processing and scientific applications. Mainframe computers are larger and more powerful than most midsize
systems. They are usually faster, have more memory capacity, and can support more network users and peripheral
devices. They are designed to handle the information processing needs of large organizations with high volumes of
transaction processing or with complex computational problems. Supercomputers are a special category of
extremely powerful mainframe computer systems designed for massive computational assignments.
• The Computer Systems Concept. A computer is a system of information processing components that perform
input, processing, output, storage, and control functions. Its hardware components include input and output
devices, a central processing unit (CPU), and primary and secondary storage devices. The major functions and
hardware in a computer system are summarized in Figure 3.10 .
• Peripheral Devices. Refer to Figures 3.14 and 3.22 to review the capabilities of peripheral devices for
input, output, and storage discussed in this chapter.
3-
,Chapter 03 - Computer Hardware
KEY TERMS AND CONCEPTS
1. Binary representation (108):
The presence or absence of electronic, magnetic, or optic “signals” in the computer’s circuitry or in the media it
uses. There are only two possible states or conditions - presence or absence. These may also be interpreted as
on/off, or 0/1.
2. Central processing unit (93):
The component of a computer system that includes the circuits controlling the interpretation and execution of
instructions. The CPU includes the arithmetic-logic unit and the control unit.
3. Computer system (92):
A computer system consists of input and output devices, primary and secondary storage devices, the central
processing unit, and other peripheral devices.
4. Computer terminal (85):
A terminal is any device that enables both input and output between a user and a computer via
telecommunications link.
5. Cycles per second (94):
Denoted as Hz, cycles per second is a measure of the speed of the computer's timing circuits or internal clock.
The higher the number, the faster the CPU. Cycles in the millions per second range are called megahertz
(MHz), in the billions per second range are called gigahertz (GHz), and in the trillions per second range are
called terahertz (THz).
6. Direct access (109):
A method of storage where each storage cluster has a unique address and can be individually accessed in
approximately the same period of time as any other cluster without having to first search through preceding
sectors. Instructor's note: these storage positions are not necessarily individual bits of memory. On disk-
based media, an individual memory location is called a "cluster". Clusters may vary in size between disk
partitions but will remain uniform in capacity within a partition. Cluster size can only be set during partition
formatting.
7. Graphical user interface (97):
A design approach that enables users to interact with a computer by manipulating images or "icons" that
represent objects or actions.
8. Information appliance (86):
Hand-held microcomputer devices. Most of these devices now include wireless connectivity to the Internet and
innovative I/O methods such as touch screens, pen-based handwriting recognition, and detachable keypads.
9. Magnetic disks (112):
Data storage technology that uses magnetised spots on metal or plastic disks.
a. Floppy disk (112):
Small, flexible, plastic disk enclosed in a protective envelope and hard plastic shell. It holds data in the
form of magnetised spots. These were once widely used to provide a removable direct access storage
capability for microcomputer systems.
3-
, Chapter 03 - Computer Hardware
b. Hard disk (113):
A secondary storage medium consisting of metal disks covered with a magnetic recording surface. It
holds data in the form of magnetised spots. Microcomputers typically have at least one built in hard drive.
They may also have the capacity to add additional internal and/or external drives. Single drive storage
capacity ranges up to 1.5 TB and continues to increase.
c. RAID (Redundant array of independent disks ) (113):
A RAID array comprises two or more interconnected microcomputer hard disk drives and their controllers.
They provide, fault tolerant storage capacities. RAID arrays are characterized by their ability to continue
running without data loss even if one drive should fail.
10. Magnetic stripe (105):
A strip of magnetic tape embedded in a plastic card and widely used for credit/debit cards and identification
cards. These stripes hold up to 200 bytes of information.
11. Magnetic tape (113):
A plastic tape with a magnetic surface on which data can be stored by selective magnetisation of portions of
the surface. Tapes can only be read sequentially from beginning to end. As a result, magnetic tapes are
primarily used for data archiving and data backups.
12. Mainframe system (89):
This category comprises large, fast, and powerful computer systems. Processing speeds range up to billions of
instructions per second. Primary memory may consist of hundreds or thousands of gigabytes. Usage
considerations include cost, space, air-conditioning, and uninterrupted power supplies. They are used for
computationally tense applications such as managing airline reservation systems or financial transactions in
banking institutions.
13. Microcomputer (83):
Also called a "Personal Computer" or "PC", these are small computers, ranging in size from a “computer on a
chip” to a small typewriter-size unit. These networked workstations are critical to individuals and business
professionals.
14. Midrange system (87):
Larger, more powerful, and more expensive than most microcomputers but are smaller, less powerful, and less
expensive than most large mainframe computer systems, these computers are used to handle large-scale
processing for integrated enterprise wide manufacturing, distribution, and financial applications, large websites,
or data warehouse management and related data mining and online analytical processing (OLAP) applications.
15. Minicomputer (88):
This category comprises mid-range computer that might be used as a high-end workstation for computationally
intense applications. They are often found in industrial process control systems such as computer aided
manufacturing (CAM) applications. These computers may also serve as front-end servers to relieve mainframe
computers of telecommunications and network management tasks. While microcomputers would fit on, under,
or next to a desk, minicomputers are larger and are generally not co-located with its users.
16. MIPS (94):
An acronym standing for Millions of Instructions per Second. This is a way of measuring relative CPU speed
(see also cycles per second – measured in MHz)
17. Moore's law (94):
Moore predicted that the number of transistors per integrated circuit will double every 18 to 24 months.
3-
