The document discusses the history and evolution of computer hardware from the first generation of vacuum tube computers to current generation computers using grand-scale integrated circuits. It describes the main components of computer hardware including the central processing unit, primary and secondary storage, and input/output devices. It also covers topics such as computer memory, microprocessors, and emerging technologies.

1. Computer Hierarchy
• The first generation of computers,
from 1946 to about 1956, used
vacuum tubes to store and process
information.
• The second generation of computers,
from 1957 to 1963, used transistors
for storing and processing
information.

2. Computer Hierarchy
• Third-generation computers, from 1964 to 1979,
used integrated circuits for storing and
processing information.
• Early to middle fourth-generation computers,
from 1980 to 1995, used very-large-scale
integrated (VLSI) circuits to store and process
information.
• Late fourth-generation computers, from 1996 to
the present, use grand-scale integrated (GSI)
circuits to store and process information.

3. Computer Categories
• Supercomputers
• Mainframe Computers
• Midrange Computers
• Workstations
• Notebooks and Desktop Computers
• Appliances

4. Hardware

5. • Hardware refers to the physical equipment used
for the input, processing, output and storage
activities of a computer system.
• Central processing unit (CPU) manipulates the
data and controls the tasks performed by the
other components.
• Primary storage internal to the CPU;
temporarily stores data and program instructions
during processing.

6. Hardware
• Secondary storage external to the CPU;
stores data and programs for future use.
• Input technologies accept data and
instructions and convert them to a form
that the computer can understand.
• Output technologies present data and
information in a form people can
understand.

7. Hardware (Continued)
• Communication technologies provide
for the flow of data from external computer
networks (e.g. the Internet and intranets)
to the CPU, and from the CPU to
computer networks.

8. How the CPU Works

9. The Central Processing Unit
• Central processing unit (CPU) performs the actual
computation or “number crunching” inside any computer.
• Microprocessor made up of millions of microscopic
transistors embedded in a circuit on a silicon chip.
• Control unit sequentially accesses program
instructions, decodes them and controls the flow of data
to and from the ALU, the registers, the caches, primary
storage, secondary storage and various output devices.

10. CPU (Continued)
• Arithmetic-logic unit (ALU) performs the
mathematic calculations and makes
logical comparisons.
• Registers are high-speed storage areas
that store very small amounts of data and
instructions for short periods of time.

11. How the CPU Works
• Binary form: The form in which data and instructions can be read
by the CPU – only 0s and 1s.
• Machine instruction cycle: The cycle of computer processing,
whose speed is measured in terms of the number of instructions
a chip processes per second.
• Clock speed: The preset speed of the computer clock that times
all chip activities, measured in megahertz and gigahertz.
• Word length: The number of bits (0s and 1s) that can be
processed by the CPU at any one time.
• Bus width: The size of the physical paths down which the data
and instructions travel as electrical impulses on a computer chip.
• Line width: The distance between transistors; the smaller the
line width, the faster the chip.

12. Advances in Microprocessor
Design
• Moore’s Law is that microprocessor complexity
would double every two years as a result of the following
changes:
– Increasing miniaturization of transistors.
– Making the physical layout of the chip’s components as
compact and efficient as possible.
– Using materials for the chip that improve the conductivity
(flow) of electricity.
– Targeting the amount of basic instructions programmed
into the chip.

13. Microprocessors & Microcontrollers
• The two most common microprocessor
architectures are complex instruction
set computing (CISC) and reduced
instruction set computing (RISC).
• Microcontrollers are computer chips,
embedded in products and technologies,
that usually cost less and work in less-
demanding applications than
microprocessors.

14. Computer Memory
• Two basic categories of computer
memory: Primary storage and secondary
storage.
– Primary stores small amounts of data and
information that will be immediately used by
the CPU.
– Secondary stores much larger amounts of
data and information (an entire software
program, for example) for extended periods of
time.

15. Memory Capacity
• Bit: Short for binary digit (0s and 1s), the
only data that a CPU can process.
• Byte: An 8-bit string of data, needed to
represent any one alphanumeric character
or simple mathematical operation.

16. Hierarchy of Memory Capacity
• Kilobyte (KB): approximately one thousand
bytes.
• Megabyte (MB): approximately one million
bytes (1,048,576 bytes, or 1,024 x 1,024).
• Gigabyte (GB): actually 1,073,741,824 bytes
(1,024 x 1,024 x 1,024 bytes).
• Terabyte: One trillion bytes.
• Petabyte: Approximately 1015
bytes.
• Exabyte: Approximately 1018
bytes.

17. Primary Storage
• Primary storage or main memory stores three types of
information for very brief periods of time:
– Data to be processed by the CPU;
– Instructions for the CPU as to how to process the data;
– Operating system programs that manage various aspects of the
computer’s operation.
• Primary storage takes place in chips mounted on the
computer’s main circuit board, called the motherboard.
• Four main types of primary storage: register, random
access memory (RAM), cache memory and read-only
memory (ROM).

18. Main Types of Primary Storage
• Registers: registers are part of the CPU with the
least capacity, storing extremely limited amounts
of instructions and data only immediately before
and after processing.
• Random access memory (RAM): The part of
primary storage that holds a software program
and small amounts of data when they are
brought from secondary storage.
• Cache memory: A type of primary storage
where the computer can temporarily store blocks
of data used more often.

19. Primary Storage (Continued)
• Read-only memory (ROM): Type of
primary storage where certain critical
instructions are safeguarded; the storage
is nonvolatile and retains the instructions
when the power to the computer is turned
off.
• Flash memory: A form of rewritable read-
only memory that is compact, portable,
and requires little energy.

20. Secondary Storage
• Memory capacity that can store very large
amounts of data for extended periods of
time.
– It is nonvolatile.
– It takes much more time to retrieve data
because of the electromechanical nature.
– It is cheaper than primary storage.
– It can take place on a variety of media

21. Secondary Storage
• Magnetic tape: A secondary storage medium on
a large open reel or in a smaller cartridge or
cassette.
• Sequential access: Data access in which the
computer system must run through data in
sequence in order to locate a particular piece.
• Magnetic disks: A form of secondary storage
on a magnetized disk divided into tracks and
sectors that provide addresses for various
pieces of data; also called hard disks.

22. Secondary Storage
• Hard drives: A form of secondary storage that
stores data on platters divided into concentric
tracks and sectors, which can be read by a
read/write head that pivots across the rotating
disks.
• Direct access: Data access in which any piece
of data be retrieved in a nonsequential manner
by locating it using the data’s address.
• Magnetic diskettes: A form of easily portable
secondary storage on flexible Mylar disks; also
called floppy disks.

23. Optical Storage Devices
• Optical storage devices: A form of secondary storage
in which a laser reads the surface of a reflective plastic
platter.
• Compact disk, read-only memory (CD-ROM): A form
of secondary storage that can be only read and not
written on.
• Digital video disk (DVD): An optical storage device
used to store digital video or computer data.
• Fluorescent multilayer disk (FMD-ROM): An optical
storage device with much greater storage capacity than
DVDs.

24. More Storage Options
• Memory cards: Credit-card-size storage
devices that can be installed in an adapter
or slot in many personal computers (i.e.
memory sticks, thumb drives).
• Expandable storage devices:
Removable disk cartridges, used as
backup storage for internal hard drives of
PCs.

25. Enterprise Storage Systems &
RAID
• Enterprise storage system: An
independent, external system with
intelligence that includes two or more
storage devices.
• Redundant arrays of independent disks
(RAID): An enterprise storage system that
links groups of standard hard drives to a
specialized microcontroller that
coordinates the drives so they appear as a
single logical drive.

26. Storage Area Networks (SANs)
• Storage area network (SAN): An enterprise
storage system architecture for building special,
dedicated networks that allow rapid and reliable
access to storage devices by multiple servers.
• Storage over IP: Technology that uses the
Internet Protocol to transport stored data
between devices within a SAN; sometimes
called IP over SCSI or iSCSI.

27. Network-Attached Storage
• Network-attached storage (NAS) device
is a special-purpose server that provides
file storage to users who access the
device over a network; plug-and-play.

28. Input and Output Technologies
• Input technologies allow people and other
technologies to put data into a computer. The
two main types of input devices are:
– human data-entry devices include keyboards,
mouse, trackball, joystick, touchscreen, stylus and
voice recognition;
– source-data automation devices input data with
minimal human intervention (e.g. barcode reader).
• Speed up data collection;
• Reduce errors;
• Gather data at the source of a transaction or other event.

29. Input and Output Technologies
(Continued)
• Output generated by a computer can be
transmitted to the user over several output
devices and media.
– Includes monitors, printers, plotters and voice.

30. Multimedia Technology
• Multimedia technology is the computer-
based integration of text, sound, still
images, animation and digitized motion
video.
• Merges capabilities of computers with
televisions, VCRs, CD players, DVD
players, video and audio recording
equipment, music and gaming
technologies.

31. Emerging Technologies
• Grid computing involves applying the resources of
many computers in a network to a single problem at the
same time.
• Utility computing (also called subscription computing
and on-demand computing) is when a service provider
makes computing resources and infrastructure
management available to a customer as needed for a
charge based on specific usage rather than a flat rate.
• Nanotechnology refers to the creation of materials,
devices and systems at a scale of 1 to 100 nanometers
(billionths of a meter).