Its a detailed discription on STORAGE DEVICES

1. STORAGE DEVICES
By: Abhishek Srivastava

2. Introduction to Storage
Computer data storage, often called storage or
memory, is a technology consisting of computer
components and recording media used to retain
digital data.

3. Memory Hierarchy
Storage

4. Primary Memory
Primary
storage often
referred to
simply as
memory, is the
only one
directly
accessible to
the CPU. The
CPU
continuously
reads
instructions
stored there
and executes
them as
Registers
• These are located inside the processor. Each register typically holds a
word of data (often 32 or 64 bits
• Registers are the fastest of all forms of computer data storage.
Cache
• It is an intermediate stage between ultra-fast registers and much
slower main memory.
• Most actively used information in the main memory is just duplicated in
the cache memory, which is faster, but of much lesser capacity.
Main
• Main memory is directly or indirectly connected to the central
processing unit via a memory bus
• It consists of RAM & ROM

5. Secondary Memory
Secondary
storage differs
from primary
storage in that it
is not directly
accessible by
the CPU. The
computer
usually uses its
input/ output
channels to
access
secondary
storage and
transfers the
desired data
using
Magnetic
• It is usually used as secondary storage. The time taken to
access a given byte of information stored on a hard disk is
typically a few thousandths of a second, or milliseconds.
• It includes tape, Hard disk, floppy Disk etc.
Optical
• An optical disk is a high-capacity storage medium. An
optical drive uses reflected light to read data.
• It includes CD-R, CD-RW, DVD, Blue ray etc.

6. Types of Storage Techniques

7. Magnetic Storage
A magnetic
disk's
medium
contains
iron
particles,
which can
be
polarized—
given a
magnetic
charge—in
one of two
directions(i.
e. north or
Diskettes (floppy disks)
Hard disks
High-capacity floppy disks
Disk cartridges
Magnetic tape

8. How Magnetic Memory works ?

9. Hard Disk Drive
 Typically mounted inside the
computer
 Provides permanent storage
and quick access
 Stores information either on
small disks called platters or
in integrated memory chips
 Read and write operations
are managed by the controller
 Data is transferred to and
from the motherboard by the
host adapter

10. Floppy Disk Drives
 Rapidly becoming obsolete
but still found in legacy
applications
 Most recent configuration
accepted a removable 3
1/2" disk with a storage
capacity of 1.44 MB
 Traditionally assigned drive
letters A: and B:
 Power supplied through a
4-pin Mini power
Connector (Molex)
 Data transferred to
motherboard through a 34-
pin keyed ribbon cable

11. Optical Storage
Data is
recorded to
this type of
media by
stamping
irregularities
onto the
surface of the
disc, or
"burned" into it
using a laser,
in a spiral
pattern that
runs from the
inside to the
outside of the
disk.
Compact Disk
Digital versatile Disk
Blue Ray Disk

12. How Optical Device works?

13. Compact Disk
 Used for digital data
storage
 Formats include read-only
(CD-ROM), write-once
audio and data
storage (CD-R), and
rewritable media (CD-RW).
Storage capacity ranges
from 650-900MB.

14. DVD
 DVD discs can be single or
double sided.
 each DVD side may contain a
second invisible "layer" to
increase the disc's storage
capacity.
 4.7GB capacity(single-sided/
single-layer)
 8.5GB capacity (single-sided/
double-layer)
 9.4GB capacity (double-sided/
single-layer)
 17.1GB capacity (double-sided/
double-layer)

15. Blue Ray Disk
 High-density optical
disc created with a
blue laser
 Used to store HD
video and large
amounts of data
 25-50GB storage
capacity single-layer
 50-100GB storage
capacity dual-layer

16. Flash Memory
 Flash memory cards
have high-capacity
storage laminated
inside a small piece of
plastic
 Flash memory cards
do not need a drive
with moving parts to
operate

17. Flash Memory Talk
Example
s of Flash
Memory
Compact Flash (CF)
xD-Picture Card (xD)
Smart Media (SM) Card
Secure Digital (SD) card
Multi Media Cards (MMC)

18. Tertiary Memory
 Tertiary storage or tertiary
memory, provides a third level
of storage. Typically it
involves a robotic mechanism
which will mount and
dismount removable mass
storage media into a storage
device according to the
system's demands; this data
is often copied to secondary
storage before use.
 Examples are Tape libraries&
optical juke boxes

19. Memory Addressing
 Memory is a collection of
cells, each with a unique
physical/memory
address
 Each cell can hold one
byte or 8 bits
 The cell contents can
change, but the cell address
or reference to the cell is

20. Storage Memory Terms
1 Byte
1 Kilobyte (KB)
1 Megabytes (MB)
1 Gigabytes (GB)
1 Terabytes (TB)
1 Petabyte (PB)
1 Exabyte (EB)
= 8 bits
≈ 1 Thousand Bytes
≈ 1 Million Bytes
≈ 1 Billion Bytes
≈ 1 Trillion Bytes
≈ 1 quadrillion Bytes
≈ 1 quintillion Bytes

21. THANK U ALL…