UNIT 1

Overview Of Computers
Topic:
TYPES OF COMPUTER
Computers can be categorized into four main types:

1. Supercomputers
2. Mainframes
3. Minicomputers
4. Microcomputers

These are categories in terms of processing power, size, cost, efficiency, and the types of tasks they are
used for.

1. Supercomputers:
Super computers are the most powerfull and expensive computers that can process data quickly.

Characteristics:

 Speed: Supercomputers are the fastest computers available, capable of performing trillions of
calculations per second (measured in FLOPS Floating Point Operations Per Second).
 Modern supercomputers: can exceed 1 exaFLOP (10^18 FLOPS).
 Size: Typically supercomputers are very large in size and can occupy entire rooms or even floors
of a building.
 Cost: Extremely expensive, often costing tens to hundreds of millions of dollars.
 Efficiency: Highly efficient for parallel processing tasks, such as weather forecasting, scientific
simulations, and complex calculations.
 Examples:
 Summit (USA) 200 petaflops: Summit is a supercomputer used for complex scientific research
and big data tasks.
 Fugaku (Japan) over 442 petaflops: Fugaku is the world's fastest supercomputer, used for various
scientific and medical studies.
 Sierra (USA) 125 petaflops: Sierra is a supercomputer focused on nuclear simulations and
national security research.

Advantages:

1. Extremely high processing power.

2. Capable of handling largescale simulations and complex calculations.
3. Crucial for research in fields like climate science, astrophysics, and artificial intelligence.
Disadvantages:

1. Very high cost.

2. Requires specialized environments (cooling, power supply).
3. Complex to program and maintain.
2. Mainframe Computers:
Characteristics:
These are the second powerful and expensive computers than supercomputers.

 Speed: Mainframes are powerful, though not as fast as supercomputers, with processing speeds
measured in MIPS (Millions of Instructions Per Second).
 Size: Mainframes are large, though smaller than supercomputers, often occupying multiple
cabinets.
 Cost: Expensive, but generally less costly than supercomputers, ranging from hundreds of
thousands to millions of dollars.
 Efficiency: Highly efficient for handling large volumes of transactions and data processing tasks.

Examples:

 IBM zSeries:
 IBM zSeries is a powerful mainframe computer used by large organizations for highvolume
transaction processing.
 Fujitsu GS21:
 Fujitsu GS21 is a mainframe computer designed for reliable and largescale business operations,
mainly in Japan.
Advantages:
1. Capable of processing large volumes of transactions simultaneously.
2. Highly reliable with extensive backup and recovery options.
3. Strong security features.

Disadvantages:
1. High cost.
2. Requires specialized environments.
3. Less versatile for generalpurpose computing compared to other types.
4. Minicomputers
Characteristics:
 Speed: Moderate(slow,normal) processing power, typically measured in millions of instructions
per second (MIPS).
 Size: Smaller in size than mainframes, often the size of a small refrigerator.
 Cost: Less expensive than mainframes, typically costing tens of thousands to hundreds of
thousands of dollars.
  Efficiency: Efficient for small to mediumsized businesses or departments needing processing
power without the scale of a mainframe.
Examples:
 PDP11 (Digital Equipment Corporation):
PDP11 was a popular minicomputer known for its versatility and wide use in the 1970s and 1980s.
 AS/400 (IBM):
AS/400 is a midrange computer system by IBM, widely used for business applications and known
for its reliability.
Advantages:
1. Costeffective for mediumscale processing tasks.
2. Easier to maintain and operate than mainframes.
3. Versatile for a variety of business applications.

Disadvantages:
1. Limited processing power compared to mainframes and supercomputers.
2. Can be less efficient for largescale data processing.
3. Microcomputers (Personal Computers)
Characteristics:
 Speed: Typically ranges from 1 to 5 GHz in processing speed, depending on the CPU.
 Size: Compact and portable, often the size of a desktop or laptop.
 Cost: Relatively inexpensive, ranging from a few hundred to a few thousand dollars.
 Efficiency: Highly efficient for personal use, small business tasks, and general computing needs.
Examples:
1. Desktop PCs (Dell, HP): Desktop PCs are personal computers used for everyday tasks at home
or work, typically requiring a separate monitor and peripherals.
2. Laptops (MacBook, Lenovo ThinkPad):
Laptops are portable computers with builtin screens and keyboards, ideal for use on the go.
3. Tablets (iPad, Samsung Galaxy Tab):
Tablets are handheld devices with touchscreens, used for browsing, media consumption, and
light computing tasks.

Advantages:
4. Affordable and accessible to a wide range of users.
5. Versatile for a variety of applications, including business, education, entertainment, and personal
use.
6. Portable (in the case of laptops and tablets).

Disadvantages:
Limited processing power compared to minicomputers, mainframes, and supercomputers.

Less suited for largescale, intensive computational tasks.

Can become obsolete relatively quickly due to rapid technological advancements.

Comparison of Computer Types

Category Processing Speed Size Cost Efficiency Use Cases

Supercomputers Highest (Exaflops) Very Large Extremely High Best for complex, largescale Scientific research
tasks

Mainframes High (MIPS) Large High Excellent for largescale processing Large
transaction enterprises,
banking,
government

Minicomputers Moderate (MIPS) Medium Moderate Good for departmentallevel Mediumsized

tasks businesses,
industrial control

Microcomputers Lower (GHz) Small Low Efficient for personal/general

tasks Personal use, small
businesses,
education