Hard Disk Drive

What is a Hard Disk Drive?

A hard disk drive , though technically a secondary  form of storage.
A hard disk drive (HDD) , hard disk, drive or fixed disk is an electro -
mechanical data storage device that uses magnetic storage to
store and retrieve digital data using one or more rigid rapidly rotating
platters coated with magnetic heads, usually arranged on a moving
actuator arm, which read and write data to the platter surfaces. Data
is accessed in a random -access manners, meaning that individual
blocks of data can be stored and retrieved in any order. HDDs
are a type of non-volatile storage, retaining stored data even when
powered off.  The features of HDDs that have made them an
irreplaceable  component in our computers are their high capacity for
storing data and the high speeds at which they can access it at relatively
lower  cost. They come in various interfaces and specification such as
IDE, EIDE, SCSI, SATA, and SATA II.

Hard Disk

                                                                         












Best Manufacturers Company of Hard Disk :-     

• Western Digital
• Seagate 

Other Company of Hard Disk :-

• Toshiba
• Samsung
• SanDisk
• Hitachi
• G-Tech     

Western Digital Hard Disk some categories Blue, Black,Purple, 

Red, Gold  :- 

• WD Blue PC HDD

Solid Performance and Reliability for Everyday Computing .

PC Storage Designed Specifically for Desktops, Laptops, 

and All-In-One PCs.

Specifications :-

Features    WD Blue 2.5"    WD Blue - 5400 RPM    WD Blue - 7200 RPM

 Capacity       320GB-2TB         500GB -2TB                       500GB -1TB     
Form factor       2.5",7mm          3.5"                                    3.5"      
RPM Class        5400                       5400                               7200
Interface            SATA 6GB/s      SATA 6GB/s                   SATA 6GB/s

• WD Black PC HDD

Black Hard Disk

Maximum Performance for Power Computing
for Power Computing.
Highlights
Performance storage available in up to 6TB capacities.
Designed for creative professionals, gamers, and system builders.Western Digital’s StableTrac and Dynamic Cache Technology increase reliability and optimize
performance. 

Specifications

Features	WD Black 2.5", 7mm	WD Black 2.5",  9.5mm	WD Black 3.5"
Capacity	250GB - 500GB	1TB	500GB - 6TB
Interface	SATA 6b/s	SATA 6Gb/s	SATA 6Gb/s
RPM Class	7200	7200	7200

• WD Purple Surveillance HDD

Uncompromising Storage for 24/7, Always On Security Systems

Highlights

• Engineered specifically for surveillance security systems.
• Supports up to 360TB/yr workload rate.
• Tuned for write-intensive, low bit-rate, high stream-count applications typical to most surveillance applications.
• Prioritized write-operations for maximized surveillance performance.
• TLER & ATA streaming support.
• Support for more than eight bays

Specifications

Features	WD purple 7200 RPM	WD purple 5400 RPM
Form Factor	3.5"	3.5"
Interface	SATA 6 G/B	SATA 6 G?B

CPU ( Central Processing Unit )

A central processing unit ( CPU ) , also called a central processor or
main processor, is the electronic circuitry within  a computer that
executes instructions that make up a computer program. The CPU
Performs basic arithmetic , logic , controlling , and input/output
( I/O ) operations specified by the instructions in the program.

Top Manufacturers Company of CPU :-

• Intel
• AMD

Major Model of Intel Processor:-

• Pentium 1,2,3,4
• Celeron
• Pentium M and Celeron M for mobile devices
• Pentium Dual Core
• Core Solo
• Core Duo
• Core 2 Duo
• Core 2 Quad
• Core i3, i5 , i7 

Intel Processor Generation :-

• 1st Generation Processor - Nehalem was introduced in 2010
• 2nd Generation Processor- Sandy Bridge was released in 2011
• 3rd Generation Processor - Ivy Bridge was introduced in 2012
• 4th Generation Processor - Haswell was released in 2013
• 5th Generation Processor - Broadwell was introduced in 2015
• 6th Generation Processor - Sylake was  released in august 2015
• 7th Generation Processor - Kaby Lake released in 2016
• 8th Generation Processor - Kaby Lake R introduced in 2017
• 9th Generation  Processor - Coffee Lake introduced by Intel in late 2017
• 10th Generation Processor- Cannon Lake / Ice lake  started in 2018
• 11th Generation Processor - Tiger lake 

AMD processor some model Number :-

• AMD Ryzen 3 3100
• AMD Ryzen 3 3250U
• AMD Ryzen 3 3300X
• AMD Ryzen 3 4300U
• AMD Ryzen 3 PRO 4450U

CPU Implementation:-

Cache- A CPU cache is a hardware cache used by the central processing unit
 ( CPU )of a computer to reduce the average cost ( time or energy ) to access
data from the main memory . A cache is a smaller , faster memory, closer to
 a processor core, which stores copies of the data from frequently used main
memory locations.
Clock rate:- Most CPUs are synchronous circuits, which means they employ
 a clock signal to pace their sequential operations. The clock signal is produced
by an external oscillator circuit that generates a consistent number of pulses
each second in the form of a periodic square wave. The frequency of the clock
pulses determines the rate at which a CPU executes instructions and ,
consequently, the faster the clock, the more instructions the CPU will execute
each second.

Voltage regulator module:- Many modern CPUs have a die-integrated power
managing module which regulates on- demand  voltage supply to the CPU
circuitry allowing it to keep balance between performance and power consumption.

MOTHERBOARD

Computer Motherboard

A motherboard is the main PCB ( Printed Circuit Board ) sometimes alternative
 known as a logical board or a main board of a Personal Computer or in fact any
complex electronic system. It is basically a flat fibre glass platform which hosts
the CPU ( Central processing system ), the main electronic components, device
 controller chips , main memory slots, slots for attaching the storage devices and
other subsystems.

Motherboard Components
Socket and Ports:-
Main power socket:- On the top part of the rear of your computer system,
which supplies power from the electric mains to the computer system.
This socket is the main power supply unit of your computer.
PS/2 mouse port:- Next you will find a small round green colored port with
seven holes and a small logo of the mouse printed next to it. This is where
your PS/2 Mouse will be plugged in.
PS/2 keyboard port:- Right next to it you find another similar purple colored
port with the keyboard logo printed next to it. This is where your PS/2
keyboard will be plugged in.
Fan housing :- There are two fan housings at the back of your computer.
One fan housing is a part of the power supply unit and the other will be
somewhere below it to cool off the heat generated by the CPU.
Serial ports:- It is a 9- pin connector used to attached the old serial port mouse,
hand-held scanners, modems, joysticks, game pads, and the other such devices.
Parallel port:- It is a 25- pin connector used to attach parallel port printers,
modems, external hard disk drives, etc
Audio jacks:-There are three audio jacks in your computer system.
USB ports:- The USB port is designed to connect multiple peripheral devices in
a single standardized interface and has a plug and play option that allows devices to
be connected and disconnected without having to restart or turning off the computer.
It has replaced many serial and parallel port devices such as mouse, printer, modems,
joysticks, game pads, scanners digital cameras, and other such devices.
VGA ports:- A 15-pin connector that connects the signal cable of the monitor
to the computer.

Best manufactures company are follows:-

• Intel
• AOpen
• ASUS
• ABIT
• BIOSTAR
• GIGABYTE
• MSI

MOTHERBOARD FORM FACTORS AND TYPES

• ATX
• AT
• BABY AT
• BTX
• DTX
• LPX
• FULL ATX
• FULL AT
• MICROATX
• NLX

Generation of Computer RAM

Double Data Rate Synchronous Dynamic Random-Access Memory ( DDR SDRAM )

Generation	Release Year	Voltage	Common Type and Speed
DDR	1998	2.5/2.6	PC3200 = 400 MHz/ 3200 Mbps
DDR 2	2007	1.8	DDR 2 -800 (PC2-6400) = 800MHz/6400 Mbps
DDR 3	2007	1.5/1.35	DDR3-1333 (PC3-10600) = 1333MHz/10,600Mbps
DDR 4	2014	1.2/1.05	DDR4-2400 (PC4-19200)= 2400MHz/19200Mbps

Best RAM 2020

• Kingston HyperX  Fury
• Corsair Vengeance LED – best RAM
• Corsair Dominator Platinum RGB – best High-end RAM
• HyperX Fury RGB 3733MHz – best high frequency RAM
• G.Skill Trident Z RGB DC – best double capacity memory
• Adata Spectrix D80 – best gaming RAM
• G.Skill TridentZ Royal – best RGB RAM
• Corsair Vengeance LPX – best Low-Profile RAM
• G.Skill Mac RAM – best Mac RAM
• Crucial Ballistix Sport – best Laptop RAM

RAM ( RANDOM ACCESS MEMORY )

What is a RAM?

The memory system in the computer that is easily read from

and written to by the processor in the RAM. In the RAM,

any address may be accessed at any time, i.e, any memory

location can be accessed in a random manner without going

through any other memory location. The access search time

for all the memory locations in the same. RAM is the main

memory of computer system. The RAM is a very fast memory,

both for reading and writing information. The information

 written in it is retained as long as the power supply is on.

All information stored in the RAM is lost when the power

supply is switched off.

The two main classes of RAM are Static ( SRAM ) and

Dynamice RAM ( SRAM )

Static RAM ( SRAM )

A static RAM is made from an array of flip-flops, where each

flip-flop maintains a single bit of data within a single memory

address or location.

A static RAM retains its data without external refresh as long

as electricity is available.The other features of SRAM are as

follows:-

• It is a type of semiconductor memory.
• It does not require any external refresh to keep its data intact.
• It is used for high-speed registers,caches and small memory  

banks such as router buffers.

• It has access times in the range of 10 to 30 nanoseconds and,

hence, allows for very fast access.

• It is very expensive.

Dynamic RAM ( DRAM )

A dynamic RAM keeps its data only if is accessed by special logic 

called refresh circuit - on a continuous basic . This circuitry reads

the data of each memory cell very fast, irrespective of weather 

the memory cell is being is being used at that time by the computer

or not. The memory cell are constructed in such a way that the 

reading action itself refreshes the contents of the memory. If not 

done on a regular basic , the DRAM will lose its contents of the 

memory . If it has uninterrupted power supply . Because of this

refreshing action , the memory is called dynamic. The other features

of DRAM are as follows:-

• It is the most general type of memory . It is used in all PCs 

for their main memory system.

• It has a much higher capacity.
• It is cheaper than SRAM.
• Due to the refresh circuitry, it is slower than SRAM.

Read Only Memory ( ROM )

The Read Only Memory , which is a secure memory , is not affected

by any interruption in the power supply . It is a non-volatile memory, 

i.e, information stored in it is not lost even if the power supply goes 

off. It is used for permanent storage of information and possesses 

random access properties.

The essential purpose of the ROM is to store the Basic Input/Output

system ( BIOS ) of the computer. The BIOS commands the processors

to access its resources on receiving power supply to the system.

The different types of ROMs are as follows:-

Programmable Read Only Memory ( PRAM )

Data is written into a ROM at the time of manufacture. However, a user
can program the contents with a special PROM programmer. PROM
provides flexible and economical storage for fixed programs and data.

Erasable Programmable Read Only Memory ( EPROM )

This lets the programmer erase the contents of the ROM and reprogram it.
The contents of EPROM cells can be erased with ultraviolet light using an
EPROM  programmer. This type of ROM provides more flexibility than a
ROM during the development of digital systems. Since these are able to
retain the stored information for a longer duration duration, any change can
be easily made.

Electrically Erasable Programable Read Only Memory ( EEPROM )

In this type of ROM , the contents of the cell can be erased electrically by
applying a high voltage. The EEPROM need not removed physically for
 reprogramming.

     

COMPUTER HARDWARE

  WHAT IS COMPUTER HARDWARE ?

Computer hardware is the collection of physical parts of a

computer system.

Examples of computer hardware are follows:-

Input devices of computer :- Mouse, Keyboard and etc.

Output devices of computer :- Monitor, printer and etc.

Secondary devices :-    Hard Disk, CD, DVD, and etc.

List of some computer hardware

• RAM ( RANDOM ACCESS MEMORY )
• MOTHERBOARD
• CPU  ( CENTRAL PROCESSING UNIT )
• HDD ( HARD DISK DRIVE )
• SMPS ( SWITCHED - MODE POWER SUPPLY )
• MONITOR 
• KEYBOARD
• MOUSE
• UPS ( UNINTERRUPTIBLE POWER SUPPLY )

What is a computer?

A computer is an electronic device that can be 
instructed to carry out sequences of arithmetic
 or logical operations automatically via computer
programming .