introduction to computer for physics students.

1. Introduction to Computer
Lecture 3
Computer Systems
Instructor : Bilal
bilalaftabraja@gmail.com

2. During the Second Lecture …
• We talked about the evolution of computers
• How initial computers were mechanical, and
then came electro-mechanicals, then tube-
based, and finally transistor based, and how
the future belongs to quantum computers
• We discussed how the size is drastically
decreasing with time and how their capability
is increasing year by year

3. Today’s Goal
1. To learn to classify computers according
to their capability and targeted
applications
2. To find out about the essential building
blocks that make up a modern computer

4. Computer Types According to Capability
• Supercomputers
• Mainframes
• Servers
• Desktops
• Portables

5. Supercomputers (1)
• State-of-the-art machines designed to perform
calculations as fast as the current technology allows
• Used to solve extremely complex and large-scale
problems: weather prediction, simulation of atomic
explosions; aircraft design; movie animation
• Cost tens of millions of dollars
• Unique in that unlike mainframes &
personal computers, designed to focus
all their resources and capabilities on a
single task at a time

6. Supercomputers (2)
• Early supercomputers used a single or a few
processors working in parallel
• Those processors were custom-built for the
supercomputers, and were, therefore, very
expensive
• Modern supercomputers use the same
processors that are used in desktop PCs.
They, however, are designed to use 1000’s of
them working together in parallel

7. Why use many not-so-
powerful processors
working in parallel
Why not just design a
single, really powerful
processor
?
?

8. The Champion: ASCI White
• Most powerful computer as of February 2002
• Capable of 12.3 trillion calculations/sec
– 74,000 times faster than Cray 1 (1976)
– 1,000 times faster than Deep Blue (1997)
• Designed for complex 3-D simulations
required for testing nuclear weapons
• Powered by 8192 microprocessors
• 6 TB of memory; 160 TB of storage capacity

9. Mainframe Computers (1)
• Also called “Enterprise Servers”
• Designed for performing multiple, intensive
tasks for multiple users simultaneously
• Used by large businesses (e.g. banks, e-
commerce sites), military, and industrial
organizations

10. Mainframe Computers (2)
• Designed for very-high reliability
• Can be serviced/upgraded while in operation
• Generally consist of multiple processors,
GB’s of memory, and TB’s of storage
• Cost in millions of dollars

11. Servers/Minicomputers (1)
• The name minicomputers used to define
the class of computers that lies between
personal computers and mainframes
• Then very high-end desktop computers
– called low-end or mid-range servers –
took over the role that was previously
played by minicomputers

12. Servers/Minicomputers (2)
• Low-end and mid-range servers are used by
small businesses and organizations as file-
stores, to run e-mail systems and Web sites
• Generally are more reliable than desktops, but
not as solid as the mainframes
• Generally consist of 2 or more processors,
GB’s of memory, and TB’s of storage
• Costs in hundreds of thousands of dollars

13. Desktop Computers (1)
• Also called microcomputers
• Low-end desktops are called PC’s and high-end
ones “Workstations”
• Generally consist of a single processor only,
some times 2, along with MB’s of memory, and
GB’s of storage

14. Desktop Computers (2)
• PC’s are used for running productivity
applications, Web surfing, messaging
• Workstations for more demanding tasks like
low-end 3-D simulations and other engineering
& scientific apps
• Are not as reliable and fault-tolerant as servers
• Workstations cost a few thousand dollars; PC
around a $1000

15. Mobile Computers (1)
• Laptops, palmtops, and wearable computers are
very capable computers but are light-weight and
consume very little power
• Laptops (also called notebook computers) generally
weigh around 2kg, use special low-power
processors, typically have 256MB memory, 40GB of
storage, can work for more than 2 hours on battery
• Their usage is similar to that of PCs
• They cost in the range of $1500-2500

16. Mobile Computers (2)
• Palmtops, also known as PDA’s - Personal Digital
Assistants
• Weigh less than a pound, have very low-power
processors, KB’s of memory, MB’s of storage capacity
• Can run for many hours on AA batteries
• Used as an electronic version of a pocket diary. Also
for Web surfing and e-mail or even as mobile phones
• Palmtops cost $200-600

17. Mobile Computers (3)
• Wearables are small in size, carried in a pocket,
worn on the arm, waist, or head or elsewhere
on the body
• Capability similar to PDA’s, but more expensive
• They are always ON, and always accessible.
That is, the user can always enter and execute
commands, even while walking around or doing
other activities
• Each soldier of the future will be fitted with one

18. Ranking w.r.t. installed number
• PC’s
• PDA’s
• Workstations
• Servers
• Wearables (will take the top spot in future)
• Mainframes
• Supercomputers

19. Now that we have learnt about the various
types of computers and about their typical
applications, let’s move on to a new topic
Let’s now find out about the essential
components that are present in every type
of computers

20. At the highest level, two things
are required for computing
Hardware: The physical equipment in a
computing environment such as the
computer and its peripheral devices
(printers, speakers, etc.)
Software: The set of instructions that
operates various parts of the hardware.
Also termed as “computer program”

21. All computers have the following
essential hardware components:
Input – the component through which a user instructs a
computer about what to do
Processor – the engine that processes the instructions
given by the user
Memory – where the processor stores information that is
required during its computations
Storage – where information that is required to be used
much later is stored
Output – the component that communicates the results
of a computation to the user

22. There is another quite essential component
that is present in every computer …
????

23. The Bus!

24. Keyboard Mouse
PrinterMemory
Hard
Disk
Memory
Bus
System Bus
Monitor
Compact
Disk
Processor
Integer
Unit
Control
Unit
Cache
Memory
Floating
Point
Unit

25. Input Devices
• Mouse
• Keyboard
• Joystick
• Camera
• Microphone
• Scanner

26. What’s a

27. Port
The connection point at which we connect
input and output devices to a computer

28. Many Types of Ports
1. Parallel
2. Serial
3. SCSI
4. USB
5. Firewire

29. Processor
• Pentium
• Celeron
• Athlon
• PowerPC
• StrongARM (PDA)
• Crusoe (Laptops)
• SPARC (Workstations)

30. Memory/Storage
• RAM
• Punch cards
• ROM
• Hard disk
• Floppy disk
• Tape
• CD
• DVD

31. Classifying Memory/Storage
• Electronic (RAM, ROM)
magnetic (HD, FD, Tape), optical (CD, DVD)
• Volatile (RAM), non-volatile (HD)
• Direct access (RAM, HD), serial access (Tape)
• Read/write (HD, RAM), read-only (CD)

32. Output Devices
Printer
Plotter
Speakers
Monitor

33. input device or output device?

34. modem

35. modulatordemodulatorom dem

36. Modem is an example of a device
that acts both as an input as well
as an output device
• Can you think of any other such dual-
purpose devices?
– Network card
– Touch screens

37. What have we learnt today?
What are the various types of computers
with respect to their size, capability,
applications (FIVE TYPES)
The five essential components of any
computer are input devices, processor,
memory, storage and output devices

38. Next time we’ll find out about
1. What are the major building blocks
of a modern personal computer?
2. How those building blocks are put
together to form a PC?