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Components of Computer
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Contents
Ports
Memory Microprocessors
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Ports
A port is an interface or point of attachment.
It is used to connect the peripheral devices
with the computers such as printers,
Keyboards or mouse.
Each type of port operates at certain speed.
The speed is measured in Kilobytes per
second or megabytes per second.
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Standard Computer Ports
Mouse and Keyboard Ports Two USB Ports
Serial Port
Parallel Port
Audio Ports
Network Port
Modem Port
Monitor Port
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Standard Computer Ports
Serial Port: are connected to externalmodems.
Parallel Port: Most Common uses are toconnect older printers to the computer.
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Standard Computer Ports
USB Ports: The USB port is one of the mostpopular and most used ports that come standard onnearly every computer manufactured today.
USB stands for "universal serial bus" and serves as a
standard for both Windows-based computers andApple's Macintosh. USB computer ports typically
enable connections with smaller devices.
USB is also useful for "plug and play" applications in
which a device is connected to the USB computer portand the driver is automatically located by the operating
system, reducing or eliminating the need for a software
boot via disk.
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Audio Ports: The green speaker port is foryour headphone or desktop speakers. The
pink microphone port is for a small
microphone. The yellow speaker out isdesigned for home stereo system.
Network Port: For internet connection
Modem Port: It connects your computer to aphone line.
Monitor Port: Most monitors connect to the
three row port on the right side of the image.
Standard Computer Ports
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Types of Ports
Different Types of Ports are as follow
Serial Ports
Parallel Ports
Serial PortsA type of port that transmits one bit at a time is calledserial port. It is usually used to connect devices thatdo not required fastest data transmission like mouseand keyboard.
Serial port often refer as communication ports. Datatravel over the serial port at 115 Kilobytes per second.
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Parallel Ports
Parallel ports are used to connect the devices
that transfer many bits at a time. It usually
used to connect devices that required fastdata transmission like printer and scanner.
Parallel ports are often called as Line Printer
ports.
The speed of Parallel port is 12 Mbps.
It is faster than serial port.
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UART
Universal Asynchronous Receiver
Transmitter.
Inside the computer, a chip called UARTconverts parallel data from the bus into serial
data that flows through a serial cable.
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Memory
When we receive some instruction or informationwe retain them in our memory. Similarly acomputer stores the instructions for solving a
problem , the data to be processed , theintermediate results and the final results until they
are displayed. This storage unit s known as computer memory or
store.
It consists of chips either on the motherboard or ona small circuit board attached to the motherboard.
This electronic memory allows the CPU to storeand retrieve data quickly.
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Memory Two types of built-in-memory:
Permanent memory.
Some memory chips retain the data they hold,
even when the computer is turned off. This
type of permanent memory is called
nonvolatile.
Non-Permanent memory.
Other chips in fact, most of the memory in a
microcomputer-lose their contents when the
computers power is shut down. This type of
nonpermanent memory is called volatile.
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Nonvolatile Memory
Nonvolatile chips hold data even when the computer isunplugged.
During normal use, the data in these chips is only read
and used- not changed- so the memory is called read only
memory (ROM). Specifically, chips that cannot be changed are called
programmable read only memory (PROM).
PROM chips are often found on hard drives and printers.
They contain the instructions that power the devices.
These instructions, once set, never need to be changed.
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Nonvolatile Memory
When a computer is turned on, it must know how to start.
ROM contains a set of start-up instructions called the
basic input output system (BIOS) for a computer.
FLASH MEMORY
Flash memory is a special type of nonvolatile memory.
It is often used in portable digital devices for storage.
Digital cameras, portable MP3 players, USB keychain
storage devices all use flash memory.
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Volatile Memory Volatile memory requires to store data.
The volatile memory in a computer is called randomaccess memory (RAM).
RAMs job is to hold programs and data while they are
in use.
Physically, RAM consists of chips on a small circuit
board.
Single inline memory modules (SIMMs) and dual inline
memory module (DIMM) chips are found in desktopcomputers.
While the smaller, small outline DIMM (SO-DIMM)
chips are found in laptop computers.
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RAM
Random Access Memory
It is also called main memory or direct accessmemory or read/write memory.
A program must be loaded into RAM beforeexecution.
Data and instructions can be read and modified.
It play an important role in processing of computer.
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Types of RAM
SRAM (Static Random Access Memory)
Retains contents as long as power is
maintained.
Faster than DRAM.
SRAM is more expensive.
CPU does not wait to access data.
It is usually used to build a very fast memory
known as cache.
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Types of RAM
DRAM (Dynamic RAM)
Must be constantly refreshed.
Requires an electric current to maintain its
electrical state.
The electrical charge of DRAM will decrease
with time that may result in lose of data.
Used for most PC memory because of size
and cost.
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Read Only Memory (ROM)
Programs and data that are permanently
recorded at the factory.
The instructions can only be read and cannotbe deleted.
Cannot be changed by the user.
When the computer is switched on ,theinstructions in the ROM are automatically
loaded into the memory of the computer.
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Types of ROM
PROM
Programmable ROM
This form of ROM is initially blank.
The user can write data and programs on it.
The user can write data and instructions on it
only once.
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EPROM
Stands for Erasable Programmable
Read Only Memory
It is initially blank
The user can write data and programs
on it. The data and program written on it can
be erased using ultraviolet rays.
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EEPROM
Stands for Electronically ErasableProgrammable Read Only Memory
It is initially blank The user can write data and programs on it.
The content of EEPROM can be modified
easily. The data and program written on it can be
erased using electrical pulses.
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Cache Memory
Small block of very fast temporary memory
Speed up data transfer It is located inside or close to CPU chip.
It is faster than RAM
Instructions and data used most frequently ormost recently.
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Cache
Step 1Processor
requests
data or
instructions
Step 2Go to address in main
memory and read
Step 3
Transfer to main CPU and cache
Next processor request Look first at cache Go to memory
P
R
O
CE
S
S
O
R
R
A
M
Cache
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Types of Cache
Internal cache Level 1 (L1) Built into microprocessor
Up to 128KB or 256 KB
External cache Level 2 (L2) Separate chips
256KB or 512 KB SRAM technology Cheaper and slower than L1 Faster and more expensive than memory
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Measuring Storage Capacity
KB kilobyte 1024 bytes
Some diskettes Cache memory
MB megabyte
Million bytes RAM
GB gigabyte Billion bytes
Hard disks CDs and DVDs
TB terabytes
Trillion bytes Large hard disks
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Registers
A location used for temporarily hold data
or instructions at the moment of execution
The storage capacity of registersmeasures in bytes (can be 1,2,4 or 8
bytes registers).
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Registers in ALU
Accumulator (Acc) storing intermediate results of computations
Status Register (SR) to store the status of the result
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Registers in CU
Program Counter (PC) to contain the address of next instruction to
be executed keep a record of the sequence of execution.
Instruction Register (IR) to contain instruction that is being executed.
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Registers in CU
Memory Address Register (MAR) to store the address of the data or instruction
to be processed
Memory Data Register (MDR) to store data or instruction to be processed.
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Registers in CPU
CPU
CU ALU
PC
MAR
MDR
IR
PSR
Acc
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Microprocessor
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Single Core The single-core has only one processor mounted in a chip that
is connected to the motherboard. In a single-core or traditional processor the CPU is fed strings
of instructions it must order, execute, then selectively store in
its cache for quick retrieval. When data outside the cache is required, it is retrieved through
the system bus from random access memory (RAM) or from
storage devices. Accessing these slows down performance to the maximum
speed the bus, RAM or storage device will allow, which is far
slower than the speed of the CPU.
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Dual Core
A dual-core processor has two microprocessors
mounted in one single chip.
In a dual core processor each core handles incomingdata strings simultaneously to improve efficiency.
Just as two heads are better than one.
Now when one is executing the other can be accessingthe system bus or executing its own code.
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Benefits of Dual Core
Dual-core processors can be highly appreciated inheavy gaming or in intensive data transfers using asingle computer.
For example, when you are downloading huge files and
you are just using a single-core, you would surelyexperience lagging of the data transfer. However, dual-cores would not give you such scenario since the task isdivided.
This makes your time to be used more wisely. It's likefalling in line in a store where there are two cashiers.You would surely pay your goods faster having twocashiers than just having one.
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Difference Between
Single Core & Dual Core Another difference of the single and dual-core
processors is the need for multi-threading
software. Dual-core processors run with software that
can read multi-threading. This technology is commonly found in new
computers especially in a server environmentthat makes data processing really an ease.
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Difference Between
Dual Core & Core 2 Duo
core2duo started before dual core. core2duo is under the core2 brand, dual core is under the
Pentium brand. core2duo limits processor speed to 3.3 GHz, dual core
limits it to 2.5 GHz. core2duo offers cache size of up to 6MB l2 cache with
scope for l3 cache as well, dual core limits it to around 2
MB. Both are based on the core micro architecture. core2duo comes for higher prices, and is simply better
than dual core.
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Difference Between Dual Core
& Multiprocessor In dual core, resources are shared and the
cores reside on the same chip.
In multi-processor system, there are twoseparate CPUs with their own resources.
A multi-processor system is faster than a
system with a dual core processor.
while a dual core system is faster than asingle-core system, all else being equal.
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Quad Core
Four microprocessorsper chip.
Intel says we can expect
a 70 percentperformance increaseover the single anddouble computing cores.
Intel Launches ThreeNew Quad-coreProcessors
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Multi Core
A multi-core processor is a processing system composed of twoor more microprocessors .
The largest boost in performance will likely be noticed inimproved response time while running CPU-intensive processes,like antivirus scans or searching for folders.
For example, if the automatic virus scan initiates while a movieis being watched, the application running the movie is far lesslikely to be starved of processor power, as the antivirus program
will be assigned to a different processor core than the onerunning the movie playback.