1. Types of Computers Supercomputers Mainframe computers Minicomputers
Microcomputers
There are four types of computers
Supercomputers
Mainframe computers
Minicomputers
Microcomputers
desktop
laptop or notebook
tablet PC
Handheld computers
Palm computers
Persona digital assistants

2. Super Computers
: An extremely fast computer that can perform hundreds of millions of instructions per second.
Most superior on all levels
Fastest
Capable of processing at MIPS (Millions of Instructions Per Second)/ expected to keep increasing
Most Spacious for Data storage
Capable of saving data in trillion of bytes (more than 500 TB).
Most costly
Prices begin at about $4 million.
Largest
Occupy large halls
Application Areas
-Primarily used for very demanding applications, where huge amount of data input is involved.
Number Crunching
Weather Forecasting
Aircraft design
Nuclear Research
Seismic Analysis
Space Program

3. Mainframe Computers A bit moderate as compared with Super Computers.
Application Areas
-Primarily used by medium to large size companies as a central computing resource.
For large processing applications in business areas such as - accounting, - sales and marketing, production, and - human resources.
A bit moderate as compared with Super Computers.
First developed computers in the history (50’s)
Specially wired for connecting 100’s of terminals.
Speed
Capable of processing at 10’s of MIPS.
Capacity for Data storage
Capable of saving data in trillion of bytes (up to 500 TB).
Cost Range
$100,000 or more.
Size
Occupy large rooms

4. Mini Computers Smaller & cheaper than main frame in its capabilities.
Came in 70’s to offload the overloaded Mainframes.
Technological advancements result in increased capabilities & reduced prices.
New versions are called Mid Range Computers.
Speed -Comparable to main frame now.
Capacity for Data storage
Capable of saving data in trillion of bytes (up to 100 TB or more).
Application Areas
-Primarily used by sub-departments of companies to offload the company mainframe’s work.
e.g. an inventory department might use a mini to provide better control of stock and to make predictions about future needs.

5. Micro Computers Introduced in early 80’s.
Can be sub-classed on speed and portability.
SUPERMICROS
High powered (near to minis)
Used in different processing approaches
Example: Workstation Micros (Network server, high quality graphics-designing etc.)
-Leading Manufactures for workstations are SUN Microsystems
Application Areas
-Popularly used as a server machine in a networked environment.
-Widely use for business applications.

6. Micro Computers DESKTOP MICROS PORTABLE MICROS
Keep on increasing in processing power etc.
Mostly in a personal access.
Can run many applications at a time (needs operating system support).
PORTABLE MICROS
Very Compact & Lightweight.
As powerful as desktops.
Used by mobile users
Laptop – about 11 lbs/ can be fitted inside an airplane tray.
Notebook – nearly 7 lbs/ can be accommodated in a brief case.
Palmtop – 2/3 lbs / can fit into a pocket or purse.
Capabilities: Hand-writing recognition, personal organization tools, travel information, communication means.

7. Microcomputers Least powerful Widely used Four types Desktop
Notebook or laptop
Tablet PC
Handheld
smartphones
Application Areas
-Almost every where (because of ever falling cost).
-Education -Entertainment -Businesses -Mobile Professions (Salespersons, Field data collecting staff etc.)
Lease powerful computers, but most widely used
Fastest growing computer
Have students begin discussing the microcomputer and wireless connectivity

8. …Micro Computer Hardware
Input/ Output Devices
All devices (a variety of them) which do the conversion from human understandable to computer understandable data & vice versa.
Keyboard, mouse – most common input devices. Students give e.gs
Monitors, printers – most common output devices. Students give e.gs

9. Automatic input devices
MICR
involves the recognition by a machine of special formatted character printed in ink.
very speedy and accurate. Used mainly in banks on Cheques and Deposit slips
BAR coding
Bar code readers can read bar codes—patterns of printed bars.
The reader emits light, which reflects off the bar code and into a detector in the reader. The detector translates the code into numbers. Commonly found in supermarkets. Couriers.

10. Automatic input devices
OMR
- involves the marking of pre printed form with a pen/typed.
-used in marking A,B,C,D answer sheets, National Lottery.
OCR
-can be classified as just special scanners.
 A scanner shines light onto the image and interprets the reflection.
Optical character recognition (OCR) software translates scanned text into editable electronic documents.

11. Automatic input devices
SMART CARDS
-a plastic card in which is embedded a microprocessor chip. Most common smart card applications-: credit/debit cards, computer security system, e-cash…etc
Voice Recognition devices
Visual/ Image Recognition devices
- mostly used in computer security systems(biometrics)