Both NOR and NAND Flash memory were invented by Dr. Fujio Masuoka from Toshiba in 1984. The name 'Flash' was suggested because the erasure process of the memory contents reminds a flash of a camera, and it's name was coined to express how much faster it could be erased "in a flash".
Flash memory is a form of non-volatile memory that can be electrically erased and rewrite, which means that it does not need power to maintain the data stored in the chip. In addition, flash memory offers fast read accessing times and better shock resistance than hard disks. These characteristics give a good explaination the popularity of flash memory for applications such as storage on battery-powered devices. However, USB flash drives are a convenient way to transport data from one location to another. USB have several advantages over conventional data transportation methods including:
1. Compact in design
2. Light weight
3. Low cost to purchase
4. Ever increasing capacities (up to 8GB or more)
Whilst disadvantages include:
1. Higher cost per Gb
2. Slower than conventional hard disks
3. Higher risk of losing data
In general, solid state storage devices such as memory cards or USB flash drives offer greater reliability than their conventional hard disk counterparts as they contain no moving parts. Faults are nearly always related to either an onboard component malfunction or poor assembly. Frequently in order to recover the data, it's necessary to fault find by tracing the electronic signals in the devices themselves and replacing / repairing the faulty component, or modifying boards / components to create a workaround on the device.
It's important to remember that if the data contained on the faulty device is of value, and it is necessary to have it recovered by experienced technicians. Data on solid state devices can often be rendered unrecoverablely due to incorrect recovery procedures not being noted.
Typical USB memory stick / card / pen drive failure & data loss symptoms: The device will no longer be recognised by the computer when inserted; or the device will be recognised but appear empty or the device will be recognised incorrectly or show the wrong storage capacity