CS101 Introduction to Computing Lecture 4 Computer Systems

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CS101 Introduction to ComputingLecture
4Computer Systems
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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

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Todays 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

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Computer Types According to Capability

• Supercomputers
• Mainframes
• Servers
• Desktops
• Portables

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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

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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 1000s of them working together
  in parallel

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Why use many not-so-powerful processors working
in parallel
?
Why not just design a single, really powerful
processor Post your answers on the CS101 message
board
?
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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

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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

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Mainframe Computers (2)

• Designed for very-high reliability
• Can be serviced/upgraded while in operation
• Generally consist of multiple processors, GBs of
  memory, and TBs of storage
• Cost in millions of dollars

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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

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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, GBs
  of memory, and TBs of storage
• Costs in hundreds of thousands of dollars

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Desktop Computers (1)

• Also called microcomputers
• Low-end desktops are called PCs and high-end
  ones Workstations
• Generally consist of a single processor only,
  some times 2, along with MBs of memory, and GBs
  of storage

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Desktop Computers (2)

• PCs 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

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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

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Mobile Computers (2)

• Palmtops, also known as PDAs - Personal Digital
  Assistants
• Weigh less than a pound, have very low-power
  processors, KBs of memory, MBs 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

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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 PDAs, 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

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Picture of a wearable computer
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Ranking w.r.t. installed number

• PCs
• PDAs
• Workstations
• Servers
• Wearables (will take the top spot in future)
• Mainframes
• Supercomputers

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Now that we have learnt about the various types
of computers and about their typical
applications, lets move on to a new topicLets
now find out about the essential components that
are present in every type of computers
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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

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Well have a lot to say about software during the
duration of this courseHowever, for the rest of
todays discussion, lets concentrate on hardware
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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

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There is another quite essential component that
is present in every computer ????
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The Bus!
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Keyboard
Mouse
Integer Unit
Control Unit
Compact Disk
Cache Memory
Floating Point Unit
System Bus
Hard Disk
Processor
Memory Bus
Printer
Memory
Monitor
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Input Devices

• Mouse
• Keyboard
• Joystick
• Camera
• Microphone
• Scanner

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Whats a Port?
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Port

• The connection point at which we connect input
  and output devices to a computer

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Many Types of Ports

1. Parallel
2. Serial
3. SCSI
4. USB
5. Firewire

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Processor

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

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Memory/Storage

• RAM
• Punch cards
• ROM
• Hard disk
• Floppy disk
• Tape
• CD
• DVD

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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)

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Output Devices

• Printer
• Plotter
• Speakers
• Monitor

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modeminput device or output device?
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mo?dem
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modulator
modem
demodulator
o
m
d
e
m
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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 cared
• Touch screens

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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
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Next time well 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?