1. Portable Memory
External Hard drives

2. What is a hard drive?
The hard drive is the main data storage device in a computer. The computers operating system, software and data and files are stored on the hard drive
External hard drives are hard drives that sit in a casing and connect to your computer through a cable.

3. History of External Hard Drives
1953: IBM invented 1st external hard drive the size of a washing machine
1956: IBM ships the first hard drive in the RAMAC 305 system. The drive holds 5MB of data at $10,000 a megabyte. The system is as big as two refrigerators.
1963: IBM comes up with the first removable hard drive, the 1311, which has six 14-inch platters and holds 2.6MB.
1970: General Digital Corporation (renamed Western Digital in 1971) is founded in California.
1978: First RAID (Redundant Arrays of Independent Disks) technology patent is filed
1979: A group headed by Al Shugart founds disk-drive manufacturer Seagate Technology.
1979: Seagate introduces the ST-506 drive and interface, which is then used in all early microcomputer implementations.
1980: IBM introduces the first gigabyte hard drive. It is the size of a refrigerator, weighs about 550 pounds, and costs $40,000.

4. History of External Hard Drives cont’d.
1984: Western Digital makes the first Winchester hard drive controller card for the IBM PC/AT--and sets an industry standard.
1985: Western Digital produces the first ESDI (Enhanced Small Device Interface) controller board, which allows larger capacity and faster hard drives to be used in PCs.
1986: The official SCSI spec is released; Apple Computer's Mac Plus is one of the first computers to use it.
1988: Prairie Tek releases the 220, the first 2.5-inch hard drive designed for the burgeoning notebook computer market
1996: IBM stores 1 billion bits per square inch on a platter.
1998: IBM announces its Microdrive, the smallest hard drive to date. It fits 340MB on a single 1-inch platter.
2004: The first 0.85-inch hard drive, Toshiba's MK2001MTN, debuts. It stores 2GB on a single platter.
2006: Seagate's Momentus notebook hard drive is the first 2.5-inch model to use perpendicular magnetic recording, which boosts its capacity up to 160GB.
2006: Seagate releases the Barracuda , at 750GB the largest hard drive to date.
2006: Cornice and Seagate each announce a 1-inch hard drive that holds 12GB.

5. Why use an external hard drive?
To back up data
Back up data from multiple devices and have it all stored in one place
Keep data safe and secure
software malfunction,
Viruses
human error
natural disasters
Theft
Travel
Work
School

6. Types of External Hard drive
USB drives- low cost and portability.
slowest drives, transferring about 400 megabits of data per second, but they have the virtue of being compatible with almost any computer on the market.
FireWire drives - transfer for complex and large multimedia files popular among people with Apple computers transfers files about twice as quickly as USB ports.
eSATA Drives- External Serial Advanced Technology Attachment almost seven times faster than USB drives share the same channel as your computer's internal hard drive the cost can run nearly double as similarly sized USB drives; the lack of external eSATA ports on most computers and the need for an external power source.

7. Flash Drive
small data storage device that connects to your computer's USB(Universal Serial Bus) port.
thumb drive
a flash drive is typically small, cross-platform, rewritable and extremely inexpensive.
USB flash drives have effectively replaced established computer media, including Zip drives and floppy discs.

8. Memory Cards also known as flash memory cards or flash drives
have revolutionized the way data is saved, stored and exchanged among digital devices.
Originally designed for the laptop computer,
Has now evolved into a more reliable and resilient storage device than disk drives. Memory cards are now used in every digital product