ASSIGNMENT NO 2
NAME: AGHA ATTIQUE PATHAN
REG NO: (48985)
DEPT: BBA
LAST SEMESTER
SECONDARY STORAGE:
Secondary storage, also known as auxiliary storage or external
memory, is a type of data storage that provides non-volatile, long-term storage for Computer
Systems. Unlike Primary storage (e.g., RAM) which is directly accessible by the Central
Processing Unit (CPU) and is volatile, meaning it loses data when the computer is switched
off, secondary storage retains data even after the system is powered down.
Key Characteristics of Secondary Storage Devices:
Various types of secondary storage devices exist, each with their unique features and
attributes. However, some key characteristics are common among these devices:
Non-volatile: Secondary storage devices do not lose data when the computer is powered
off, ensuring that information is kept intact over time.
Slower data access: Compared to primary storage, secondary storage devices generally
have slower read and write speeds, as data transfer is not as direct or immediate.
High capacity: As mentioned earlier, secondary storage devices provide a larger storage
space for a wide range of data types and file sizes.
Cost-effective: Per unit of storage, secondary storage devices are generally less expensive
than primary storage, making them a more economical option for extensive data storage.
TYPES OF STORAGE DEVICES:
*1. Hard Disk Drives (HDDs):
HDDs are the most prevalent type of Magnetic
Storage devices, predominantly used in desktop computers and servers. They consist of one
or more rotating disks coated with a magnetic material, along with read/write heads that float
above the surface to access the data. HDD characteristics and features include:
High storage capacity: HDDs typically offer large storage capacities, ranging from a few
hundred gigabytes to several terabytes.
Slower data access: HDDs have slower read and write speeds compared to solid-state
drives due to the mechanical nature of the rotating disks and moving read/write heads.
Average reliability: HDDs are susceptible to physical damage from shocks, vibrations, and
wear over time, which could result in data loss.
Economical: HDDs generally provide a lower cost per Gigabyte of storage compared to
solid-state drives, making them an affordable option for vast storage requirements.
- *.Storage Cost:
- HDDs offer a cost-effective solution with a low cost per gigabyte, making them suitable
for industries with extensive data storage needs on a budget.
- *Rubric Score: Good (4) - Demonstrates a clear understanding of the cost factor.
- *Storage Mechanism:*
- Data is stored on magnetic platters within the HDD. These platters spin at high speeds,
and read/write heads access information by positioning themselves over the spinning platters.
- *Rubric Score: Excellent (5) - Provides a detailed and clear explanation of the storage
mechanism.
- *Example and Usage in Industry:*
- Examples of HDDs include Seagate Barracuda and Western Digital Black. HDDs are
commonly used in industries for general-purpose storage, server farms, and data centers
where economical large-scale storage is crucial.
- *Rubric Score: Excellent (5) - Provides clear examples and a thorough understanding
of industrial applications.
*2. Solid State Drives (SSDs):*
Solid-state secondary storage devices do not have any moving parts and use flash memory to
store data. This category primarily includes solid-state drives (SSDs) and USB flash drives.
The key advantage of solid-state storage is that it offers faster data access speeds and greater
reliability compared to magnetic and optical storage devices. The main types of solid-state
storage devices are:
Solid State Drive (SSD): SSDs are similar to HDDs in terms of storage capacity options
but offer much faster read and write speeds. They can be installed in desktop computers,
laptops, or external storage devices. SSDs use NAND-based flash memory to store data and
are available in various form factors, such as SATA, M.2, and U.2. Notable SSD features
include:
High-speed data access: SSDs have significantly higher read and write speeds compared
to HDDs due to the absence of moving parts.
Greater reliability: The lack of mechanical components in SSDs makes them less
susceptible to physical damage, resulting in a longer lifespan and increased reliability.
Energy efficiency: SSDs consume less power compared to HDDs, making them a more
energy-efficient storage option.
Higher cost per gigabyte: While SSD prices have dropped in recent years, they still tend
to be more expensive than HDDs on a per-gigabyte basis.
USB Flash Drive: USB flash drives are small, portable solid-state storage devices that
connect to a computer via a USB port. They use NAND-based flash memory to store data and
are available in various storage capacities, ranging from a few gigabytes to more than 1
Terabyte. USB flash drive characteristics include:
- *Storage Cost:*
- SSDs are relatively more expensive on a per-gigabyte basis but offer faster read/write
speeds and increased reliability, justifying their cost.
- *Rubric Score: Good (4) - Demonstrates a clear understanding of the cost factor.
- *Storage Mechanism:*
- SSDs store data in NAND flash memory without moving parts, enabling faster data
access and transfer speeds compared to HDDs.
- *Rubric Score: Excellent (5) - Offers a detailed and clear explanation of the storage
mechanism.
- Example and Usage in Industry:*
- Examples of SSDs include Samsung 970 EVO and Crucial MX500. SSDs find
applications in industries where speed and reliability are critical, such as high-performance
computing, gaming, and enterprise-level storage solutions.
- *Rubric Score:* Excellent (5) - Provides clear examples and a thorough understanding
of industrial applications.
*3. Optical Discs:
An optical disk is an electronic data storage medium that can be written to and read from using a low-
powered laser beam. Most of today's optical disks are available in three formats: compact disks
(CDs), digital versatile disks (DVDs) -- also referred to as digital video disks -- and Blu-ray disks,
which provide the highest capacities and data transfer rates of the three.
Optical disk storage capacities:
In 2016, Sony announced the development of a disk based on Blu-ray technology that would
hold 3.3 terabytes (TB) of data. Although Sony has yet to deliver on this promise, storage
capacities have continued to increase with each new generation of optical media:
A CD can store up to up 700 megabytes (MB) of data.
A single-layer DVD can hold 4.7 gigabytes (GB) of data, and a double-layer disk can hold
8.5 GB.
A single-layer Blu-ray disk can store 25 to 33.4 GB of data, and a quad-layer Blu-ray disk
can store up to 128 GB of data.
All three formats are available in the same size disks: 120 mm (4.7 inches) in diameter and
1.2 mm (0.05 inches) thick. The consistent sizing makes it possible for Blu-ray drives to
support DVDs and CDs and for DVD drives to support CDs. The compatibility works in only
one direction, however. CD drives can't run DVDs or Blu-rays, and DVD drives can't run
Blu-rays.
- *Storage Cost:*
- Optical discs have a low cost per unit but may become expensive for large-scale storage.
The cost per gigabyte is generally higher compared to HDDs and SSDs, making them
suitable for specific use cases.
- *Rubric Score:* Good (4) - Demonstrates a clear understanding of the cost factor.
- *Storage Mechanism:*
- Data is written and read using lasers that encode information on a reflective surface,
providing non-volatile storage.
- *Rubric Score:* Excellent (5) - Offers a detailed and clear explanation of the storage
mechanism.
- *Example and Usage in Industry:*
- Examples of optical discs include CD, DVD, and Blu-ray Disc. Industries use optical
discs for data distribution and archival purposes, especially in entertainment for movies and
music, software distribution, and scenarios where long-term, non-rewritable storage is
required.
- *Rubric Score:* Excellent (5) - Provides clear examples and a thorough understanding
of industrial applications.
*Total Score: 32 (Excellent)
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