Computer is an electronic device that processes data according to programmed instructions. It has four main components: the arithmetic logic unit for calculations, storage unit for data and instructions, control unit for coordinating operations, and input/output units. Computers have evolved through five generations from vacuum tubes to integrated circuits and modern microprocessors. They are now widely used in healthcare for tasks like record keeping, diagnostics, monitoring and surgery. Computers have two main parts - hardware which are the physical components, and software which are the programs that direct the hardware. Memory is where data and instructions are stored temporarily or permanently in bits and bytes.

1. Computer & Information
Technology
by
Engr. Zobayer Ahmed Khan

2. Computer
Computer is an advanced electronic device that
transforms data into meaningful information.
Computer is an electronic device for storing and
processing data, typically in binary form, according to
instructions given to it in a variable program

3. Computer-Block Diagram

4. Computer-Block Diagram
Arithmetic and Logical Unit
The arithmetic and logical unit is the combinational digital electronic circuit
that can perform arithmetic operations on integer binary numbers. It presents
the arithmetic and logical operation. The outputs of ALU will change
asynchronously in response to the input. The basic arithmetic and bitwise
logic functions are supported by ALU.
Storage Unit
The information or set of guidelines are stored in the storage unit of the
computer system. The storage unit provides the space to store the data or
instruction of processed data. The information or data is saved or hold in
computer memory or storage device. The data storage is the core function
and fundamental of the computer components.

5. Computer-Block Diagram
Control Unit
The control unit (CU) controls all the activities or operations which are
performed inside the computer system. It receives instructions or information
directly from the main memory of the computer.
When the control unit receives an instruction set or information, it converts
the instruction set to control signals then; these signals are sent to the central
processor for further processing. The control unit understands which
operation to execute, accurately, and in which order.

6. Computer Hardware
Computer hardware can be divided into five categories:
1. Input Hardware: Keyboard, Mouse, Trackball, Joystick, Light Pen,
Touch Screen, Bar code Reader, Optical Mark Reader (OMR),
Microphone, Digital Camera
2. Processing Hardware: The most essentials of processing hardware
are Microprocessor or CPU, Main memory or RAM
3. Storage Hardware: Floppy Disk, Hard disk, CD-ROM, DVD-ROM.
4. Output Hardware: Monitor, Printer, Plotter, Speaker, Headphone.
5. Communications Hardware: Modem, Cable, Fax Modem.

7. Computer Generation
1 First Generation: The period of first generation: 1946-1959.
Vacuum tube based.
2 Second Generation: The period of second generation: 1959-
1965. Transistor based.
3 Third Generation: The period of third generation: 1965-1971.
Integrated Circuit based.
4 Fourth Generation: The period of fourth generation: 1971-1980.
VLSI microprocessor based.
5 Fifth Generation: The period of fifth generation: 1980-onwards.
ULSI microprocessor based.

8. Computer in Health Care
Computers have become an important part in all
Medical Systems.
The computers are being used in hospitals to keep the
record of patients and medicines. It is also used in
scanning and diagnosing different diseases. ECG,
EEG, Ultrasounds and CT Scans etc. are also done by
computerized machines.

9. Computer in Health Care
Some of the major fields of healthcare in which computer are used:
Diagnostic system: Computers are used to collect data and identify
cause of illness.
Lab-diagnostic System: All tests can be done and reports are prepared
by computer.
Patient Monitoring System: These are used to check patient's signs for
abnormality such as in Cardiac Arrests, ECG etc.
Pharmacy Information System: Computer checks Drug-Labels, Expiry
dates, harmful drug side effects etc.
During Surgery: Nowadays, computers are also used in performing
surgery.

10. Functions of Computer
A Computer performs four basic functions:
1. Accept information (This is called input)
2 Store information,
3. Process the information,
4. Give out the processed information (This is called
output).

11. Characteristics & Limitations of
Computer
The major characteristics
of computer:
High speed,
Accuracy,
Automatic,
Diligence, Versatility,
Storage
Limitations of Computer:
Though a computer is a very
efficient device but there are
some limitations:
A computer cannot generate
information on its own.
A computer cannot correct
instructions if they have
mistakes.
A computer cannot come with
an original decision

12. Computers Have Two Main Parts
1. Computer Hardware
2 Computer Software
Computer Hardware:
Computer Hardware is the physical part of the computer system.
Example: Processor, Hard disk drive, Mouse, Keyboard, Monitor,
Printer, Modem.
Computer Software:
Computer Software is programs that tell the computer what to do.
Example: Microsoft Word, Microsoft Excel, Microsoft power point,
Internet Explorer.

13. Ram And Rom

14. Memory
The smallest digital data quantity measurement unit
is a ‘bit’ for traditional computers. A bit can be either
one or zero. 8 bits are then concatenated into a
‘byte’.