STORAGE DEVICES IN COMPUTER SYSTEMSBy –

Kevin JosephMBA (Energy Trading)

Information Technology

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.

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.

Units of measurement used to quantify computer data.

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.

Bit

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.

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

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.

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.

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.

SYNOPSIS

Classification of Memory

How RAM works

Random Access Memory

Computer Processor

Hard Disk

1947 to 2013

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.

Williams Tube :

Drum memory :

Universo :

IBM 350 :

Cassette Tape :

Floppy Discs :

IBM 3380

ST-506 :

Compact Discs :

Hard Discs :

Flash Memory :

Portable Static Drives :

Memory Chip/Cards :

Cloud Storage (Latest Tech) :

How data is stored ??

Data to binary code :

Numbers and alphabets are converted to binary code for processing

How data is stored in Discs and tapes

Data stored as Tracks

CD vs. DVD vs. Blu-Ray

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

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.

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.

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.

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 e-mail 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.

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.  

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.

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.

THANK YOU