Components of Computer
Contents
• Ports
• Memory
• Microprocessors
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.
Standard Computer Ports
• Mouse and Keyboard Ports
• Two USB Ports
• Serial Port
• Parallel Port
• Audio Ports
• Network Port
• Modem Port
• Monitor Port
Standard Computer Ports
• Serial Port: are connected to external
modems.
• Parallel Port: Most Common uses are to
connect older printers to the computer.
Standard Computer Ports
• USB Ports:
The USB port is one of the most
popular and most used ports that come standard on
nearly every computer manufactured today.
• USB stands for "universal serial bus" and serves as a
standard for both Windows-based computers and
Apple'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
port and the driver is automatically located by the
operating system, reducing or eliminating the need
for a software boot via disk.
Standard Computer Ports
• Audio Ports: The green speaker port is for
your headphone or desktop speakers. The
pink microphone port is for a small
microphone. The yellow speaker out is
designed for home stereo system.
• Network Port: For internet connection
• Modem Port: It connects your computer to a
phone line.
• Monitor Port: Most monitors connect to the
three row port on the right side of the image.
Types of Ports
Different Types of Ports are as follow
• Serial Ports
• Parallel Ports
Serial Ports
A type of port that transmits one bit at a time is called
serial port. It is usually used to connect devices that
do not required fastest data transmission like mouse
and keyboard.
Serial port often refer as communication ports.
Data travel over the serial port at 115 Kilobytes per
second.
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 fast
data 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.
UART
• Universal
Transmitter.
Asynchronous
Receiver
• Inside the computer, a chip called UART
converts parallel data from the bus into serial
data that flows through a serial cable.
Memory
• When we receive some instruction or information
we retain them in our memory. Similarly a
computer stores the instructions for solving a
problem , the data to be processed , the
intermediate 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
on a small circuit board attached to the
motherboard.
• This electronic memory allows the CPU to store
and retrieve data quickly.
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.
Nonvolatile Memory
• Nonvolatile chips hold data even when the computer is
unplugged.
• 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.
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.
Volatile Memory
• Volatile memory requires to store data.
• The volatile memory in a computer is called random
access memory (RAM).
• RAM’s 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
desktop computers.
• While the smaller, small outline DIMM (SO-DIMM)
chips are found in laptop computers.
RAM
Random Access Memory
• It is also called main memory or direct access
memory or read/write memory.
• A program must be loaded into RAM before
execution.
• Data and instructions can be read and modified.
• It play an important role in processing of computer.
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.
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.
Read Only Memory (ROM)
• Programs and data that are permanently
recorded at the factory.
• The instructions can only be read and cannot
be deleted.
• Cannot be changed by the user.
• When the computer is switched on ,the
instructions in the ROM are automatically
loaded into the memory of the computer.
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.
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.
EEPROM
• Stands for Electronically Erasable
Programmable 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.
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 or
most recently.
Cache
P
R
O
C
E
S
S
O
R
Step 1
Processor
requests
data or
instructions
Step 3
Transfer to main CPU and cache
R
Cache
A
M
Step 2
Go to address in main
memory and read
Next processor request
• Look first at cache
• Go to memory
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
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
Registers
• A location used for temporarily hold data
or instructions at the moment of execution
• The storage capacity of registers
measures in bytes (can be 1,2,4 or 8
bytes registers).
Registers in ALU
• Accumulator (Acc)
– storing intermediate results of computations
• Status Register (SR)
– to store the status of the result
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.
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.
Registers in CPU
CU
ALU
CPU
PC
MAR
MDR
IR
PSR
Acc
Microprocessor
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.
Dual Core
•
A dual-core processor has two microprocessors
mounted in one single chip.
•
In a dual core processor each core handles incoming
data strings simultaneously to improve efficiency.
•
Just as two heads are better than one.
•
Now when one is executing the other can be
accessing the system bus or executing its own code.
Benefits of Dual Core
• Dual-core processors can be highly appreciated in
heavy gaming or in intensive data transfers using a
single computer.
• For example, when you are downloading huge files
and you are just using a single-core, you would surely
experience lagging of the data transfer. However,
dual-cores would not give you such scenario since the
task is divided.
• This makes your time to be used more wisely. It's like
falling in line in a store where there are two cashiers.
You would surely pay your goods faster having two
cashiers than just having one.
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 environment
that makes data processing really an ease.
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.
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 two
separate 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 a
single-core system, all else being equal.
Quad Core
•
Four
microprocessors
per chip.
•
Intel says we can expect
a
70
percent
performance
increase
over the single and
double computing cores.
•
Intel Launches Three
New
Quad-core
Processors
Multi Core
A multi-core processor is a processing system composed of two
or more microprocessors .
The largest boost in performance will likely be noticed in
improved response time while running CPU-intensive
processes, like antivirus scans or searching for folders.
For example, if the automatic virus scan initiates while a movie
is being watched, the application running the movie is far less
likely to be starved of processor power, as the antivirus program
will be assigned to a different processor core than the one
running the movie playback.