Introduction to HDD

HDD Full Form: Hard Disk Drive

What is HDD?

• It is a data storage device in a computer.
• A Hard Disk that can remove the medium from one computer and carry it to another computer is called a portable disk.
• It is a secondary storage device.
• It’s stored in 0 or 1.
• The operating system, software, and most other files are stored in HDD.
• A Hard Disk Drive(HDD) is a data storage device used for storing and retrieving digital information using rapidly rotating disks (platters) coated with magnetic material. An HDD retains its data even when powered off. Data is read in a random-access manner, meaning individual blocks of data can be stored or
  retrieved in any order rather than sequentially.
• Hard Disk store data in two ways:
  1. Longitudinal Recording.
  2. Perpendicular Recording.

1. Longitudinal Recording

• Hards disk stored data using, longitudinal recording, which aligned the magnetic particle horizontally around the surface of the disk.
• Longitudinal Recording: It’s a clever way of storing data on hard drives.
• How it Works: Instead of just writing data side by side, it’s written along the length of the spinning disk.
• More Data: This allows more data to be crammed into the same space, making your hard drive store more files.
• Better Efficiency: Longitudinal recording is like stacking books on a shelf instead of placing them side by side, making data storage more efficient.

2. Perpendicular Recording

• Perpendicular Recording: It’s a smart way of storing information on hard drives.
• How it Works: Instead of laying data flat on the disk, it’s stored upright, like books on a shelf.
• More Data: This allows hard drives to store lots of data in a smaller space, making them more spacious.
• Efficiency Boost: Perpendicular recording is like fitting more books on a bookshelf by standing them up, making data storage more efficient.

These are some components of a hard disk

1. Platters.
2. Disk case.
3. Read/Write Head.
4. Cylinder.
5. Spindle
6. Disk cache.

1. Platters

• Platters: These are like the storage shelves inside a hard drive.
• What Are They: Circular, flat, and super smooth disks made of metal or glass.
• Data Storage: Information is stored on platters in the form of tiny magnetic spots.
• Stacked Layers: Hard drives often have multiple platters stacked on top of each other.
• Read and Write: A tiny arm with read/write heads accesses and records data on the platters as they spin.
• It is a circular, metal disk that is mounted inside the hard disk drive. It is made of aluminum, glass, or ceramic and coated with an alloy material that allows objects to be recorded magnetically on its surface.

2. Disk case

• The rectangular-shaped disk case holds all of the components of the hard disk drive.
• Disk Case: It’s like a protective home for your hard drive or SSD.
• Purpose: Keep your data storage device safe from dust, shocks, and physical damage.
• Types: You can find hard drive cases made of plastic, metal, or silicone.
• Portability: Some cases are small and portable, designed for on-the-go use.
• Protection: They shield your data storage device from accidents and keep it in good shape.
• Variety: Available in different sizes to fit various drive sizes.

3. Read/Write Head

• Read/Write Head: The heads read and write the information on the drive platter.
• The head writes magnetic information on the platter.
• How it Works: The head hovers just above the spinning platters, reading data from or writing data onto them.
• Accuracy: It’s incredibly precise, like a needle on a record player, ensuring your data is accurately stored and retrieved.
• Delicate: The head is fragile and can be damaged if the hard drive is bumped or jolted.
• Speed: The speed at which it moves influences how quickly data can be accessed, making it an essential component for hard drive performance.
• A read/write head is the mechanism that reads items and writes items in the
  drive as it barely touches the disk’s recording surface.

4) Cylinder

• Cylinder: A set of corresponding tracks on all sides of a hard disk is called the cylinder.
• A cylinder is the vertical section of a track that passes through all platters.
• What it Does: It groups tracks (concentric circles) on multiple platters that the read/write head can access at the same time.
• Efficiency: Allows for faster data access because the head can access data on all platters within the same cylinder in one go.
• Optimization: It’s like organizing your stuff on different shelves in a closet for quicker access. The more cylinders, the more efficient the hard drive.

5) Spindle

• Spindle: The spindle holds the platters together and the motor rotates the platters at their designated speed, which is measured in RPM.
• HDD Spindle: It’s like the axle in a spinning wheel of a hard drive.
• Purpose: The spindle holds and rotates the hard drive’s platters.
• Rotation Speed: Determines how fast the platters spin, typically 5,400 or 7,200 revolutions per minute (RPM).
• Data Access: Faster spindle speed often means quicker data access.
• Critical Component: It’s the engine that keeps your hard drive running, allowing data to be read and written as the platters spin.
• All the platter moves in the same direction.

6) Disk cache

• Disk Cache: Sometimes called a buffer, it consists of a memory chip on the hard disk that stores frequently accessed items such as data, instructions, and information.
• Purpose: Temporarily stores frequently accessed data to speed up read and write operations.
• Speed Booster: Like having a fast access drawer for files you use often.
• Size: Usually a small portion of the hard drive’s space, around 8-256MB.
• Enhanced Performance: This helps reduce load times and makes your computer feel more responsive.
• Improves Efficiency: Allows the hard drive to work more efficiently by storing commonly used data for quick retrieval.

File System in HDD

1) FAT (File Allocation Table)
2) NTFS (New Technology File System)

Aspect	FAT (File Allocation Table)	NTFS (New Technology File System)
Full Form	File Allocation Table	New Technology File System
Introduction Year	Introduced in 1977	Introduced in 1993
Compatibility	Less secure but widely compatible with various operating systems like Windows, Linux, and macOS.	More secure, primarily used with Windows operating systems. Limited compatibility with other platforms.
File Size Limit	Limited to 4 GB for individual files.	Supports very large files, up to 16 exabytes.
Partition Size Limit	Limited to 2 TB.	Supports larger partition sizes, up to 256 TB.
Security	Offers minimal security features and permissions.	Provides advanced security features, file encryption, and permission settings.
Recovery	Limited ability to recover data from disk errors or crashes.	Better data recovery capabilities due to journaling and advanced error-checking.
File Compression	Does not support file compression.	Supports file compression and provides disk space optimization.
Metadata	Limited metadata and file attribute support.	Extensive support for file attributes, timestamps, and metadata.
Use Cases	Suitable for USB drives, memory cards, and non-system partitions.	Ideal for system drives, high-capacity storage, and where data security is crucial.

Partition for HDD

1. primary partition

• Primary Partition: Windows operating systems must be located in a primary partition.
• Only the primary partition can be used to boot the operating system.
• Purpose: A primary partition is the main storage space on your hard drive.
• Number: You can have up to four primary partitions on a hard drive.
• Bootable: One primary partition can be set as the “boot” partition, where your operating system lives.
• Usage: It’s where you store your OS and important files.
• Easy Access: The computer starts from the bootable primary partition when you turn it on.

2. Extended partition

• Extended Partition: A hard disk can have only one extended partition. Extended partition can be divided into multiple logical partitions (other than OS is extended partition).
• Purpose: It’s not a place for data but a container for logical drives.
• Number: You can have only one extended partition on a hard drive.
• Logical Drives: Inside the extended partition, you can create multiple logical drives to store data.
• Flexibility: It allows you to organize and manage your data efficiently, especially when you’ve used up your primary partitions.

3. Logical Partition

• Logical Partition: Linux operating systems can be installed into and run from a logical partition.
• Purpose: Logical partitions are created within an extended partition to store data.
• Number: You can have multiple logical partitions inside one extended partition.
• Flexibility: They allow you to organize your data into separate sections within the extended partition.
• Storage: Useful for storing files, folders, or applications, similar to primary partitions but within an extended one.
• Efficiency: Logical partitions make efficient use of storage space on your hard drive.

4. Active Partition

• Active Partition: Only one partition on a computer can be set as the active partition or bootable partition. For example, if you are using Microsoft Windows then the partition that contains Windows is the active partition.
• Purpose: The active partition is where your computer’s boot loader resides, so it knows where to start up.
• One at a Time: You can only have one active partition on your hard drive.
• Boot Priority: When you turn on your computer, it looks at the active partition to begin the startup process.
• Control Center: It helps your computer know which operating system to launch if you have multiple OSs installed.

Types of interfacing in HDD

IDE (Integrated Device Electronics) / PATA (Parallel Advanced Technology Attachment)

• PATA (Parallel Advanced Technology Attachment): It has a 40-pin connector.
• The data transfer rate is 134mbbs.
• Wide Ribbon Cable: It uses a wide, flat cable with lots of wires.
• Slower Speed: Compared to newer technologies, PATA is slower in data transfer.
• when installing this type of hard drive ensure that the jumpers are correctly configured.
• Legacy Tech: It was common in older computers but has mostly been replaced by faster SATA and NVMe.
• Not So Common: You’ll rarely find PATA drives in modern PCs.
• if you have two devices connected to one IDE controller. one must be set to master and the other must be set to slave.

SATA (Serial Advanced Technology Attachment)

• SATA (Serial Advanced Technology Attachment): It has a 7-pin connector.
• Narrow Cable: It uses a narrow, simple cable with fewer wires, making it neater and more efficient.
• It is the latest high-speed type of hard drive connector.
• Faster Speed: Compared to older PATA, SATA is faster in data transfer.
• The data transfer rate is 300MB/s.As they are faster than the old IDE interface.
• Widely Used: It’s the standard for connecting internal hard drives and SSDs in most modern computers.
• Plug-and-Play: You can easily connect and disconnect SATA devices without restarting your computer.
• The latest hard drives are using this type of interface. As they are faster than the old IDE interface.

SCSI (Small Computer System Interface)

• SATA (Serial Advanced Technology Attachment): It has a 50 or 68-pin connector.
• SCSI is used to increase performance.
• Narrow Cable: It uses a narrow, simple cable with fewer wires, making it neater and more efficient.
• Faster Speed: Compared to older PATA, SATA is faster in data transfer.
• The data transfer rate is 600Mb/s
• Widely Used: It’s the standard for connecting internal hard drives and SSDs in most modern computers.
• Plug-and-Play: You can easily connect and disconnect SATA devices without restarting your computer.
• deliver faster data transfer transmission.

What are the benefits of SCSI?

• Speed: SCSI is super fast, ideal for servers and high-demand applications.
• Reliability: It’s known for stable and uninterrupted data transfer.
• Multiple Devices: You can connect several devices to a single SCSI controller, like a chain of hard drives.
• Hot Swapping: You can add or remove devices without turning off the computer.
• Compatibility: Works well with a variety of devices and operating systems.
• Primarily for Business: SCSI is commonly used in enterprise and server setups where speed and reliability are critical.

HDD Capacity and Size Information

Nowadays The highest capacity hard disk drive (HDD) is 20 terabytes.

Bit: –  0 or 1
Kb(kilobit): –  1024 bits
Byte 8 bits: –  (approximately one character in a Word document)
KB(kilobyte) : – 1024 byte
MB(Megabyte) : – 1024 Kilobytes or 1,048,576 Bytes
GB(Gigabyte) : – 1024 Megabytes or 1,073,741,824 Bytes

TB (Terabyte) :- 1024 Gigabyte or 1,099,511,627,776 Bytes
PB (Petabyte) :- 1024 terabytes or about 1,000,000,000,000,000 Bytes
EB (Extrabyte):- 1024 Petabytes or about 1,000,000,000,000,000,000 Bytes
ZB (Zettabyte) :- 1024 Exabytes or about 1,000,000,000,000,000,000,000 Bytes
Yb (Yottabyte):- 1024 Zetabytes or about 1,000,000,000,000,000,000,000,000 Bytes

How to check HDD size?

Difference between HDD and SSD

Keys	HDD (Hard Disk Drive)	SSD (Solid State Drive)
Full Form	Hard Disk Drive	Solid State Drive
Components	Contains spinning platters and a read/write head.	No moving parts use flash memory chips.
Speed	Slower due to mechanical parts and spinning platters.	Much faster with no moving parts.
Durability	Sensitive to shocks and drops due to mechanical components.	Highly durable, and resistant to shocks and vibrations.
Power Efficiency	Consumes more power, leading to reduced battery life in laptops.	Highly power-efficient, extends battery life in laptops.
Noise	Audible noise from spinning platters and head movement.	Silent operation as there are no moving parts.
Size and Weight	Larger and heavier due to mechanical components.	Compact and lightweight.
Boot Time	Slower boot times.	Almost instant boot times.
Price	Generally more cost-effective for larger storage capacities.	Slightly more expensive per GB but becoming more affordable.
Data Access	Slower data access times.	Extremely fast data access times.
Temperature Sensitivity	Sensitive to temperature variations.	Less sensitive to temperature changes.
Lifespan	Limited by mechanical wear and tear.	Longer lifespan due to lack of moving parts.
Applications	Common in traditional laptops and desktops.	Used in modern laptops, ultrabooks, and high-performance computing.

Benefits of HDD

1. Cost-Effective: HDDs provide larger storage capacities for your money, making them great for budget-conscious users.
2. High Capacity: Ideal for storing vast amounts of data, including photos, videos, and documents.
3. Long-Term Reliability: They have a proven track record of durability and reliability, making them suitable for long-term data storage.
4. Standard in Many Devices: HDDs are still the primary storage option in many laptops, desktops, and servers.
5. Easy Upgrades: You can easily upgrade your computer’s storage by swapping out or adding HDDs.
6. Compatibility: HDDs work seamlessly with a wide range of devices and operating systems.

Drawbacks of HDD