How Does a Flash Drive Work?

By Manali Oak

A flash drive is a storage device that uses flash memory. Flash memory is non-volatile. It can be electrically erased and reprogrammed. Thus it becomes a type of electrically erasable programmable read-only memory, referred to as EEPROM. Flash drives are similar in nature to conventional hard drives. They can replace these hard drives.

A word about Flash Memory
Flash drives are often used in products that operate on low power and those which have to undergo harsh conditions. The memory is non-volatile and hence flash drives do not need to be backed up by means of batteries. Flash memory is solid state. This implies that nothing in it is mechanical. Everything is purely electronic. Flash memory has a grid of columns and rows and a cell having two transistors at each of the points of intersection of the grid. A thin oxide layer separates each of the pair of transistors. Flash memory is used for the easy and speedy storage and transfer of information.

How does a Flash Drive Work?
A flash drive has to be inserted in the USB port on the computer. Latest operating systems detect the flash drive and install the necessary drivers on their own. Once the device is detected, it can be used for storing the data. The device needs to be ejected from the computer. The system prompts you when it is safe to remove the flash drive. It can be physically ejected then.

A flash drive consists of a PCB, a printed circuit board. It is covered in a plastic or rubber casing, making it sturdy. A USB connector that protrudes is covered with a removable cap. Most flash drives use type-A USB connection making it compatible with standard type-A receptacles. Hence they can be directly connected to a port on a computer.

Flash drives implement the USB mass storage device class, thus do not require any additional device drivers. When a flash drive is plugged in to a computer, what is presented to it is a block-structured logical unit. This leads to an abstraction from the complex implementation details of the flash memory devices.

During the early years of the evolution of flash drives, the devices used could not survive too many erase cycles. This made earlier flash drives unsuitable for the data needing frequent updates. To fill this lacuna, vendors devised wear-leveling techniques that relocate writes to physical memory locations. The devices of modern times are made to survive a larger number of erases.

Flash drives especially find utility in running lightweight operating systems in order to turn personal computers into network appliances. In such cases, flash drives contain the operating system and are used to boot the system. We are familiar with CDs or floppy disks used for booting purposes. But flash drives have an edge over other devices due to its low power consumption and low rate of failures. Moreover, a flash drive is small in size and portable. They enable a speedy transfer of data with less difficulty. Mostly they are plug and play devices. They demand no special training to be used. Flash drives have a large memory store, larger than memory capacities that floppies or CDs have.

USB Flash Drive
USB flash drive is a buzzword of the computer technology today. It is a flash memory storage device of the NAND-type. The essential components of this flash drive include a male type-A USB connector, a USB mass storage controller, a NAND flash memory chip and a crystal oscillator. The USB connector acts as an interface between the device and the computer. The storage controller consists of a tiny RISC processor. It also has some amount of on-chip memory (it can be ROM and RAM). The flash memory chip does the actual job of the storage of data. The crystal oscillator produces clock signals and controls data output of the device. LEDs acting as indicators, write-protect switches can be some of the other components of the flash drive.

Modern-day flash drives are equipped with security measures such as encryptions or even biometrics. They have an added advantage because of their storage capacity, speed, portability and low power consumption. A flash drive is one of the most popular storage devices. By physically storing our data, it helps us treasure our memories!

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