1. Information Technology
STORAGE DEVICES IN
COMPUTER SYSTEMS
By –
Kevin Joseph
MBA (Energy Trading)

2.  A data storage device is electronic hardware that stores
information and supports a protocol for sending and
retrieving the information over a hardware interface.
 The information can be anything that can be stored
electronically are: executable programs, source
code,
documents,
images,
spreadsheet
numbers,
database
entries,
data
logger
output, configuration data, or other text or numeric data.
 Storage devices store information which are readable by
a computer.

3.  It represents data using the binary numeral system.
 These storage devices typically store information in
files
 A file system defines how the files are organized in
the storage media.
 In Windows computers, mass-storage devices
appear as drives in My Computer.

4. Units of measurement used to quantify
computer data.
Bit
 A bit is the smallest and basic unit of information
in computing and digital communications.
 It can have only one of two values. The most common
representation of these values are 0 and1.
 The term bit is a contraction of binary digit (0 or 1).
 The two values can also be interpreted as logical
values (true/false, yes/no), algebraic signs (+/−), activation
states (on/off), or any other two-valued attribute.

5. Byte
 The term byte was coined by Werner Buchholz in July
1956, during the early design phase for the IBM
Stretch computer
 Bits are often grouped together in 8-bit clusters called bytes.
 Since a byte contains eight bits that each have two possible
values, a single byte may have 28 or 256 different values.
 The byte was the number of bits used to encode a
single character of text in a computer and for this reason it is
the smallest addressable unit of memory in many computer
architectures.

6. Kilo Byte
 A unit of computer memory or data storage
capacity equal to 1,024 (210) bytes.
 1 kB = 1024bytes = 210B is the definition used
by Microsoft Windows and Linux for computer
memory, e.g., RAM

7. Mega Byte
 The megabyte is a multiple of the unit byte for
digital information storage or transmission with
three different values depending on context
1048576 bytes (220).
 Generally for computer memory; one million bytes
generally for computer storage or transmission
rates.
 The term "megabyte" is commonly used to mean
either 10002 bytes or 1024 kilobytes.

8. Giga Byte
 The unit symbol for the gigabyte is GB.
 Today the usage of the unit gigabyte continues to depend on the
context. When referring to disk capacities it usually means
109 bytes, often stated explicitly on the manufacturer's permanent
sticker.
 A unit of computer memory or data storage capacity equal to 1,024
megabytes (230bytes) or One billion bytes.
 1 GB = 1000000000 bytes ( = 109 B) is the definition recommended
by the International System of Units (SI) and the International
Electrotechnical Commission(IEC).
 This definition is used in networking contexts and most storage
media, particularly hard drives, Flash-based storage, and DVDs, and is
also consistent with the other uses of the SI prefix in computing, such
as CPU clock speeds or measures of performance.

9. Tera Byte
 A terabyte (TB) is a measure of
computer storage capacity that is 2 to the 40th power or
approximately a trillion bytes (that is, a thousand
gigabytes).
 The prefix tera is derived from the Greek word for
monster.
 Enough words that it would take every adult in America
speaking at the same time five minutes to say them all.
 The unit symbol for the terabyte is TB.
 1 TB = 1000000000000bytes = 1012bytes = 1024
gigabytes.

10. SYNOPSIS

12. Classification of Memory

13. How RAM works
Random Access Memory
Computer Processor
Hard Disk

15. 1947 to 2013

16. There have been many different types of mass storage devices. In
the past, mass storage devices such as the floppy drive and tape
drives were used, but by 2010 they generally had been replaced by
storage devices with higher capacities.

17. Williams Tube :

18. Drum memory :

19. Universo :

20. IBM 350 :

21. Cassette Tape :

22. Floppy Discs :

23. IBM 3380

24. ST-506 :

25. Compact Discs :

26. Hard Discs :

27. Flash Memory :

28. Portable Static Drives :

29. Memory Chip/Cards :

30. Cloud Storage (Latest Tech) :

31. How data is stored ??

32. Data to binary code :
 Numbers and
alphabets are
converted to binary
code for processing

34. How data is stored in Discs
and tapes
 Data stored as
Tracks

35. CD vs. DVD vs. Blu-Ray

36. Solid State Drives
 With no moving parts, faster boot times and
less physical space, they are now the new way
we store digital media.
 It would take a staggering 14,985 IBM-350s
to match the capacity of one of these drives

37. How it Works
 Flash memory is a grid of
columns and rows with
cells that contain two
transistors at each
intersection.
 It reads info as ᾿1῀s and
᾿0῀s with each byte
defaulting as a ᾿1῀.
 To change it to a ᾿0῀
requires a process known
as Fowler-Nordheim
tunneling.

38.  The flash memory in an SSD
is known as NAND-flash.
 There are two types: SLC
(single-level cell) and MLC
(multi-level cell).
 In SLC, each cell of memory
stores one bit, and in MLC, it
usually stores two bits.
 The value of the cell is
obtained by testing the cell
with some voltage.

39. Cloud Storage
 It consists of layers — mostly
the back-end layers and
the front-end or user-end layers.
 The front-end layers are the
ones you see and interact with.
(Eg : on Accessing Gmail or a
Facebook account)
 The back-end consists of the
hardware and the software
architecture that fuels the
interface you see on the front
end.
 Because the computers are set
up to work together, the
applications can take advantage
of all that computing power as if
they were running on one
particular machine.

40.  In a cloud computing system, there's
a significant workload shift.
 Local computers no longer have to
do all the heavy lifting when it comes
to running applications.
 The network of computers that make
up the cloud handles them instead.
 Hardware and software demands on
the user's side decrease.
 Gmail : Experience with cloud
computing. Instead of running an email program on your computer, you
log in to a Web e-mail account
remotely. The software and storage
for your account doesn't exist on
your computer -- it's on the service's
computer cloud.

41. There are three main cloud storage models:
 Public cloud storage services, such as Amazon's
Simple Storage Service, provide a multi-tenant storage
environment that’s most suitable for unstructured data.
 Private cloud storage services provide a dedicated
environment protected behind an organization’s firewall.
Private clouds are appropriate for users who need
customization and more control over their data.
 Hybrid cloud storage is a combination of the other
two models that includes at least one private cloud and
one public cloud infrastructure.

42.  Cloud computing also allows for a lot of flexibility.
 Depending on the demand, you can increase how
much of the cloud resources you use without the
need for assigning specific hardware for the job.
 Or we can just reduce the amount of resources
assigned to you when they are not necessary.

43. Few examples of Cloud Storage providers :
 Dropbox
 Google Drive
 Box Inc.
 iCloud
 Amazon Cloud Drive
Disadvantages :
 Privacy issues
 If company goes bankrupt
 Limited access if company starts
charging.

44. THANK YOU