Computer Application Chapter 2
Components of the Computer System
Hardware: The tangible parts of a computer that we can touch and see are called
hardware.
Eg: Monitor, Keyboard, Mouse, CPU, Etc.
Processors: It is the brain of the computer and consists of three components
Arithmetic Logic Unit(ALU) – As the name implies it performs all calculations and
comparison operations.
Control Unit(CU)- It controls over all functions of a computer
Registers – It stores the intermediate results temporarily.
A CPU is an Integrated Circuit(IC) package that contains millions of transistors and
other components. Popular Processors are Intel core i3, core i5, core i7, AMD
Quadcore etc.
Important registers inside a CPU are
Accumulator: After performing an operation (arithmetic or logical) the result is
stored in the accumulator
Memory Address Register(MAR): It stores the address of the memory location
to which data is either read or written by the processor.
Memory Buffer Register (MBR) : It stores the data, either to be written to or
read from the memory by the processor.
Instruction Register(IR): It stores the instructions to be executed by the
processor.
Program Counter(PC): It stores the address of the next instruction to be
executed by the processor.
Motherboard: It is a Printed Circuit Board(PCB). All the major components like
Processor (Remember the processor must be compatible with the Motherboard),
RAM, ROM, HDD, Graphics card, Sound card, etc are connected to the
Motherboard.
Peripherals and Ports
Serial Port: It transmits data one bit at a time (eg: 101000001010). Its
transmission speed
is low but it is cheaper. It is suitable to transmit data over long distance.
Parallel port: It can transmit data more than one bit at a time. It is faster and
used to connect the printer.
USB (Universal Serial Bus) port: It has high bandwidth hence it is faster.
Nowadays it is used to connect all the devices like keyboard, mouse, printer,
scanner, pen drive, digital camera, mobile phones, dongle etc.
LAN port: By using this port we can connect our computer to another network
by a cable.
, PS/2(Personal System/2) poet: It is introduced by IBM for connecting keyboard
and mouse earlier.
Audio ports: It is used to connect audio devices like speakers, mic etc.
Video Graphics Array (VGA) port: It is introduced by IBM to connect a monitor
or LCD projector to a computer.
High Definition Multimedia Interface(HDMI): Through this port, we can connect
high definition quality video and multi-channel audio over a single cable.
Memory
Storage Unit(Memory Unit): A computer has huge storage capacity. It is used to
store data and instructions before starts the processing. Secondly it stores the
intermediate results and thirdly it stores information(processed data), that is the final
results before send to the output unit(Visual Display Unit, Printer, etc)
Memory measuring units are given below.
1 bit – 1 or 0(Binary Digit)
4 bits – 1 Nibble
1 bits – 1 Byte
1024 Bytes – 1 KB(KiloByte)
1024 KB – 1 MB(Mega Byte)
1024 MB – 1 GB(Giga Byte)
1024 GB – 1 TB(Tera Byte)
1024 TB – 1 PB(Peta Byte)
Two Types of the storage unit
i) Primary Storage alias Main Memory: It is further be classified into Two – Random
Access Memory (RAM) and Read-Only Memory (ROM). The one and only memory
that the CPU can directly access is the main memory at a very high speed. It is
expensive hence storage capacity is less.
RAM is volatile(when the power is switched off the content will be erased) in nature
but ROM is nonvolatile (lt is permanent). In ROM a “boot up” program called
BIOS(Basic Input Output System) is stored to “boots up” the computer when it
switched on. Some ROMs are given below.
1. PROM(Programmable ROM): It is programmed at the time of manufacturing and
cannot be erased.
2. EPROM (Erasable PROM): It can be erased and can be reprogrammed using
special electronic circuit.
3. EEPROM (Electrically EPROM): It can be erased and rewritten electrically Cache
Memory: The processor is a very high speed memory but comparatively RAM is
slower than Processor. So there is a speed mismatch between the RAM and
Processor, to resolve this a high-speed memory is placed in between these two this
memory is called cache memory. Commonly used cache memories are Level(L1)
Cache(128 KB), L2(1 MB)
ii. Secondary Storage alias Auxiliary Memory: Because of limited storage capacity of
primary memory its need arises. When a user saves a file, it will be stored in this
memory hence it is permanent in nature and its capacity is huge. Eg: Hard Disc
Drive(HDD), Compact Disc(CD), DVD, Pen Drive, Blu Ray Disc etc.
Components of the Computer System
Hardware: The tangible parts of a computer that we can touch and see are called
hardware.
Eg: Monitor, Keyboard, Mouse, CPU, Etc.
Processors: It is the brain of the computer and consists of three components
Arithmetic Logic Unit(ALU) – As the name implies it performs all calculations and
comparison operations.
Control Unit(CU)- It controls over all functions of a computer
Registers – It stores the intermediate results temporarily.
A CPU is an Integrated Circuit(IC) package that contains millions of transistors and
other components. Popular Processors are Intel core i3, core i5, core i7, AMD
Quadcore etc.
Important registers inside a CPU are
Accumulator: After performing an operation (arithmetic or logical) the result is
stored in the accumulator
Memory Address Register(MAR): It stores the address of the memory location
to which data is either read or written by the processor.
Memory Buffer Register (MBR) : It stores the data, either to be written to or
read from the memory by the processor.
Instruction Register(IR): It stores the instructions to be executed by the
processor.
Program Counter(PC): It stores the address of the next instruction to be
executed by the processor.
Motherboard: It is a Printed Circuit Board(PCB). All the major components like
Processor (Remember the processor must be compatible with the Motherboard),
RAM, ROM, HDD, Graphics card, Sound card, etc are connected to the
Motherboard.
Peripherals and Ports
Serial Port: It transmits data one bit at a time (eg: 101000001010). Its
transmission speed
is low but it is cheaper. It is suitable to transmit data over long distance.
Parallel port: It can transmit data more than one bit at a time. It is faster and
used to connect the printer.
USB (Universal Serial Bus) port: It has high bandwidth hence it is faster.
Nowadays it is used to connect all the devices like keyboard, mouse, printer,
scanner, pen drive, digital camera, mobile phones, dongle etc.
LAN port: By using this port we can connect our computer to another network
by a cable.
, PS/2(Personal System/2) poet: It is introduced by IBM for connecting keyboard
and mouse earlier.
Audio ports: It is used to connect audio devices like speakers, mic etc.
Video Graphics Array (VGA) port: It is introduced by IBM to connect a monitor
or LCD projector to a computer.
High Definition Multimedia Interface(HDMI): Through this port, we can connect
high definition quality video and multi-channel audio over a single cable.
Memory
Storage Unit(Memory Unit): A computer has huge storage capacity. It is used to
store data and instructions before starts the processing. Secondly it stores the
intermediate results and thirdly it stores information(processed data), that is the final
results before send to the output unit(Visual Display Unit, Printer, etc)
Memory measuring units are given below.
1 bit – 1 or 0(Binary Digit)
4 bits – 1 Nibble
1 bits – 1 Byte
1024 Bytes – 1 KB(KiloByte)
1024 KB – 1 MB(Mega Byte)
1024 MB – 1 GB(Giga Byte)
1024 GB – 1 TB(Tera Byte)
1024 TB – 1 PB(Peta Byte)
Two Types of the storage unit
i) Primary Storage alias Main Memory: It is further be classified into Two – Random
Access Memory (RAM) and Read-Only Memory (ROM). The one and only memory
that the CPU can directly access is the main memory at a very high speed. It is
expensive hence storage capacity is less.
RAM is volatile(when the power is switched off the content will be erased) in nature
but ROM is nonvolatile (lt is permanent). In ROM a “boot up” program called
BIOS(Basic Input Output System) is stored to “boots up” the computer when it
switched on. Some ROMs are given below.
1. PROM(Programmable ROM): It is programmed at the time of manufacturing and
cannot be erased.
2. EPROM (Erasable PROM): It can be erased and can be reprogrammed using
special electronic circuit.
3. EEPROM (Electrically EPROM): It can be erased and rewritten electrically Cache
Memory: The processor is a very high speed memory but comparatively RAM is
slower than Processor. So there is a speed mismatch between the RAM and
Processor, to resolve this a high-speed memory is placed in between these two this
memory is called cache memory. Commonly used cache memories are Level(L1)
Cache(128 KB), L2(1 MB)
ii. Secondary Storage alias Auxiliary Memory: Because of limited storage capacity of
primary memory its need arises. When a user saves a file, it will be stored in this
memory hence it is permanent in nature and its capacity is huge. Eg: Hard Disc
Drive(HDD), Compact Disc(CD), DVD, Pen Drive, Blu Ray Disc etc.
