The document provides an overview of hardware components including the central processing unit, primary and secondary storage, and input/output devices. It discusses how the CPU fetches and executes instructions in four steps and how pipelining can improve processing speed. The document also covers memory types, characteristics of processing and storage devices, and different computer system types.

1. Information Technology
Concepts
Presented by:
Dr. Akhlas Ahmed
Lecture # 01
Preston University
Hardware: Input, Processing & Output

2. Hardware Components





Central Processing Unit
Primary Storage (main
memory)
Secondary Storage
Input Devices
Output Devices
memory;

3. Hardware Components

4. Hardware Components

Control Unit


Part of the CPU that sequentially
accesses program instructions, decodes
them, and coordinates the flow of data
in
and
out
of
the
ALU,
the
register, primary storage, and even
secondary storage and various output
devices.
ALU

Portion of the CPU that performs
mathematical and logical comparisons.

5. Hardware Components

Register


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 Memory

Part of the computer that
program instructions and data.
holds

6. Hardware Components in Action




Step
Step
Step
Step
1.
2.
3.
4.
Fetch instruction
Decode instruction
Execute the instruction
Store results

7. Hardware Components in Action
Step 1:
In the instruction
phase,
the
computer’s control
unit fetches the
instruction to be
executed
from
memory.

8. Hardware Components in Action
Step 2:
Then
the
instruction
is
decoded so the
central processor
can
understand
what is to be
done.
Step 1 & 2 are called the instruction phase, and
the time is takes to perform this phase is called
the INSTRUCTION TIME (I-time).

9. Hardware Components in Action
Step 3:
In the execution
phase, the ALU
does what it is
instructed to do,
making either an
arithmetic
computation or a
logical
comparison.

10. Hardware Components in Action
Step 4:
Then the results
are stored in the
registers
or
in
memory
Step 3 & 4 are called the execution phase. The
time it takes to complete the execution phase is
called the EXECUTION TIME (E-time).

11. Hardware Components in Action


After both phases have been
completed for one instruction, they
are again performed for the second
instruction, and so on.
The instruction phase followed by
the execution phase is called a
MACHINE CYCLE.

12. Hardware Components in Action




Some central processing units can speed
up processing by using PIPELINING.
Whereby the CPU gets one instruction,
decodes another, and executes a third at
the same time.
The Pentium processor, for example, uses
two execution unit pipelines.
This gives the processing unit the ability
to execute two instructions in a single
machine cycle.

13. Processing & Memory Devices

14. Processing Characteristics and
Functions

Machine cycle time is measured in:
 Microseconds (1 millionth) for slower
computers
 Nanoseconds (1 billionth)
 Picoseconds (1 trillionth) for faster
ones.
 MIPS (Millions of Instructions Processed
per Second)

15. Wordlength and Bus Line Width


Data is moved within a computer
system not in a continuous stream
but in groups of bits. A Bit (BInary
DigiT) 0 or 1.
Therefore, another factor affecting
overall
system
performance,
particularly speed is the number of
bits the CPU can process at any one
time.

16. Wordlength and Bus Line Width
 This
number of bits is called the
Wordlength of the CPU.
 A CPU with a wordlength of 32
(called a 32-bit CPU) will
process 32 bits of data in one
machine cycle.

17. Wordlength and Bus Line Width




Data is transferred from the CPU to other
system components via Bus lines, the
physical
wiring
that
connects
the
computer system components.
The number of bits a bus line can transfer
at any time is known as bus line width.
A bus line with a width of 32 will transfer
32 bits of data a time.
Common wordlength and bus line widths
are 32 and 64.

18. Memory Characteristics and
Functions

19. Storage Capacity

20. Bill Gates made the famous remark…

“640 K ought to be enough for
anybody..” 1981….
Things have changed drastically!
2004 –PC with 512 MB of Main
Memory was standard….

21. Types of Memory

22. Types of Memory




Random Access Memory
(RAM).
Dynamic RAM (DRAM).
Synchronous
DRAM
(SDRAM).
SDRAM also has the
advantage of a faster
transfer speed between
the microprocessor and
the memory.

23. Types of Memory



Read Only Memory (ROM)
Programmable Read Only
Memory
(PROM).
Commonly used in video
games.
Erasable
Programmable
Read
Only
Memory
(EPROM). Commonly used
with industrial robots and
as a computer setup chip.

24. Read-Only Memory (ROM)




Can be read but cannot be written to
Nonvolatile
BIOS
Erasable ROM (EEPROM):



Flash memory
Can be written to and erased
Secondary storage /
Removable

25. Cache Memory


Cache Memory is a type of high-speed memory
that a processor can access more rapidly than
main memory.
Cache Memory works in conjunction with main
memory.

26. Cache Memory

A cache controller determines how often
the data is used and transfer frequently
used data to cache memory, then
deletes the data when it goes out of use.

27. Multiprocessing




A number of forms of Multiprocessing involves
the simultaneous execution of two or more
instructions at the same time.
One
form
of
multiprocessing
involves
coprocessors.
A Coprocessor speeds processing by executing
specific types of instructions while the CPU works
on another processing activity.
For example, math coprocessor chip can be used
to speed mathematical calculations, and a
graphics coprocessor chip decreases the time it
takes to manipulate graphics.

28. Massively Parallel Processing

Parallel
Processing,
a
form
of
multiprocessing
that
speed
processing
by
linking
several
processors
to
operate at the
same time, or in
parallel.

29. Massively Parallel Processing



With
Parallel
Processing,
a
problem is divided
into several parts.
Each part is “solved”
by
a
separate
processor.
The result from each
processor are then
assembled to get the
final output.

30. Secondary Storage

31. Secondary Storage (Permanent Storage)


Secondary storage devices that
store
larger
amount
of
data, instructions, and information
more permanently than allowed
with main memory.
Offers
the
advantages
of
nonvolatility, greater capacity, and
greater economy

32. 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)

33. Devices





Magnetic tapes
Magnetic disks
RAID (Redundant array of
independent/inexpensive disks)
Storage area networks (SAN)
Optical disks
Digital versatile disks (DVDs)

34. Devices

Magnetic Disks are also coated
with iron oxide; they can be thin
steel platters (Hard Disk or
Diskettes).

35. Hard Drives and Diskettes

Hard Drives




Several magnetic
disks
Read/write heads
High storage
capacity
Diskettes

Portable
magnetic media

36. Types of Secondary Storage
Magnetic Tapes and Disks, Optical Disks, and CDROMs, and DVD’s are used to store data for easy
retrieval at a later date.

37. Devices

Magnetic tapes (Common
secondary storage medium, Mylar
film coated with iron oxide with
portions of the tape magnetized to
represent bits.

38. Devices

Magnetic Disks are also coated
with iron oxide; they can be thin
steel platters (Hard Disk or
Diskettes).

39. Devices


RAID
(Redundant
array
of
independent/inexpensive disks) is a
method of storing data that generates
extra
bits
of
data
from
existing
data, allowing the system to create
“reconstruction map” so that if a hard
drive fails, it can rebuild lost data.
RAID sub-systems duplicate data on
drives. This process is called DISK
MIRRORING.

40. Devices


SAN (Storage Area
Network)
uses
computer
servers, distributed
storage devices, and
network
to
tie
everything together.
To
increase
the
speed of storing and
retrieving
data,
fiber-optic
channels are often
used.

41. Devices - Optical Disk Storage
Uses laser beam technology to read
and write.

Optical Disks a rigid disk of plastic onto which
data is recorded by special lasers that physically
burn pits in the disk.



CD-ROM (Compact Disk Read Only Memory) a
common form of optical Disks on which data, once
it has been recorded, cannot be modified.
CD-W (CD-Writeable) an optical disk that can
written upon but only once.
CD-RW (CD-Rewriteable) on optical disk that
allows personal computer users to replace their
diskettes with high-capacity CDs that can be
written upon and edited over.

42. Devices

Digital Versatile Disk Player
(DVD) look like CDs but have a
much greater storage capacity and
can transfer data at a much faster
rate.

43. Additional Devices and Media


Memory cards (The PC memory
card is like a portable hard disk that
fits into PC Card slot.
Flash memory (A silicon computer
chip that, unlike RAM, is nonvolatile
and keeps its memory when the
power is shut off).

44. Additional Devices and Media

Expendable Storage (Allow users to add
additional storage capacity by simply
plugging in a removable disk or cartridge.
The disk can be used to back up hard disk
data or to transfer large files to
classmates.

45. Secondary Storage
Comparison of methods of secondary storage

46. Input and Output Devices

47. Input Devices

Personal computer
input devices
 Keyboard
(QWERTY)
 Virtual Laser
Keyboard
Virtual Laser Keyboard

48. Input Devices

Pointing and Selecting Devices
E.g., mouse, light pen, touch pad, touch screen,
joystick, and eye-tracking device

49. Input Devices
Scanning Devices (Entering Batch Data)

Scanner (Used for repetitive information)
a.
b.
Handheld scanner
Flatbed scanner

50. Input Devices
Audio - sound that has been digitized
Voice Input
 Microphone
 Speech recognition
 Voice-to-text
software

51. Input Devices

Digital Video cameras (make it possible
for people at distant locations to conduct
videoconferences, thereby eliminating the
need for expensive travel to attend
physical meetings.

52. Input Devices

Point of Sale (POS) Devices

Credit/Debit Card Reader
Biometric devices

Read:
Fingerprints
 Face geometry


53. Input Devices
Magnetic Ink Character Recognition
(MICR) Device

54. Other Scanning Technologies



Text recognition software
Optical character recognition (OCR)
Optical mark recognition (OMR)

55. Output Devices
Display monitors

56. Output Devices
Display monitors




CRT- Cathode Ray Tube
The quality of Screen is often measured
by the number of horizontal and vertical
pixels used to create it.
A larger number of pixels per square inch
means a higher resolution, or clarity and
sharpness of the image.
For example, a screen with a 1024 x 768
resolution (786432 pixels) has a higher
sharpness than one with 640 x 350
(224000 pixels).

57. Output Devices
Display monitors



The distance between one pixel on
the screen and the next nearest
pixel is known as DOT PITCH.
The common range of dot pitch is
from .25mm to .31mm.
The smaller the number, the better
the picture.

58. Output Devices
Display monitors



Monochrome (One of the three
colors: Gray, green, or amber).
CGA (Color Graphic Adaptor) was
one of the first technologies to
display color images on the screen.
SVGA (Super Video Graphics Array)
displays are standard, providing
brilliant
colors
and
higher
resolutions.

59. Output Devices
Display monitors

LCD (Liquid Crystal Displays)



Flat Panel Displays that’s use liquid crystal
organic, oil-like material placed between two
polarizers
to form characters and graphic
images on a backlit screen.
Passive-Matrix displays, the CPU sends its
signals to transistors around the borders of the
screen, which control all the pixels in a given
row or column.
Active-Matrix display, each pixel is controlled
by its own transistor attached in a thin film to
the glass behind pixel.

60. Printers and Plotters

61. Output Devices

Printers






Daisy Wheel
Plotters
Dot Matrix
 80 Columns
 120 Columns
Ink Jet
Laser Jet
Computer Output Microfilm
(COM) Devices

62. Output Devices - Audio Output

Sound card and speakers



Sound card translates digits into
sound
Also used to capture sound
Other audio output

E.g., USB headphones

63. Computer System Types

Supercomputers


Typically
use
for
Scientific
applications, marketing
,
customer
support,
product
development).
Memory: 500+ GB

64. Computer System Types

Mainframe Computers


Typically
use
for
large
general purpose business &
Government computing need
to meet the goals.
Memory: <100+ GB

65. Computer System Types

Personal Computers
 Handheld fitting on desktop, typically use to
improve personal productivity of a worker
 Memory: 512MB - 2GB

66. Computer System Types - Portable
Computers
Notebook computers




Light weight
Battery powered
Limited expandability
Docking stations

67. Computer System Types - Tablet PCs
Type of notebook that accepts input from an
electronic pen
a.
b.
Slate model
Convertible model

68. Computer System Types 

Small computers that can be
carried in a pocket
Niche in the portable
computers market



Handheld Computers
Personal digital assistants
(PDAs)
Cell phones
Most popular manufacturers


RIM – Blackberry
Palm – Treo