Abstract
Below is a breakdown of a USB Flash Drive and the functions of it components organized into a technical description
Technical Description
Tylor Cheng
ENGL 21007: Writing for Engineers
Dr. Sara A. Jacobson
April 13th, 2021
Contents
Introduction ………………………………………………………………………………….…..2
Components ………………………………………………………………………………………3
USB Port ………………………………………………………………………………….4
USB Mass Controller Device ……………………………………………………….……5
Flash Memory ……………………………………………………………………………6
Crystal Oscillator …………………………………………………………………………7
Cover ……………………………………………………………………………….……..8
Functions of a USB flash drive ………………………………………………………………….9
Conclusion ………………………………………………………………………………….……9
Reference ………………………………………………………………………………………….11
Introduction
Although not used as much to this day with the popularization of the cloud, USB flash drives were a way to transport files physically from place to place, in a small and compact design during the late 2000s (Flash memory, n.d.). Historically flash drives were created as a container for flash memory, invented by Fujio Masuoka it was a type of data storage that could be erased and reprogrammed electronically (Flash memory, n.d.). There are two types of flash memory NOR and NAND flash-based on the different type of logic gate they use, most standard flash drives use the NAND logic gate Before the invention of flash memory the most popular type of data storage was EPROMs otherwise known as erasable programmable read-only memory, a non-volatile type of memory that could only be erased via exposure to ultraviolet light and had to be erased to be reused (Flash memory, n.d.).
The invention of flash memory and subsequently the flash drive, has made the process of erasing and writing data significantly faster from several minutes to a matter of seconds depending on the amount of data being processed as instead of data being stored in one massive chunk like in EPROMs, the information is split between several small blocks and could be erased and written electronically (Flash memory, n.d.). It is unclear who the original inventor of the flash drive was as multiple individuals have stated themselves to be the original creator, and to this day it cannot be determined.
Components
5 components make up the flash drive. The USB plug, USB mass storage controller device, flash memory chip, the crystal oscillator, and the cover. Each component plays its own part in allowing the flash drive as a whole to function and should a component malfunction the device will cease to function as intended.
Figure 1
Image of flash drive components
[Photo of USB components]. (n.d.) https://www.premiumusb.com/blog/whats-inside-a-usb-drive
USB Port
Figure 2
Image of USB Port wiring
[USB Port wiring] (n.d.) https://somanytech.com/usb-wiring-diagram-micro-usb-pinout-guide/
Starting from the left side we have the USB or universal serial bus plug, this particular piece is a male type as it contains a line of pins inside the protruding rectangular box of metal that lines up with the female type’s interior sockets. Most electronic devices containing a USB female-type port are adaptable, meaning that almost all USB male types are compatible with it. The purpose of the USB plug is to allow the transfer of data via “packets” over the interior wires of the plug and port (USB DATA TRANSFER GUIDE, n.d.). There are 3 different modes of data transfers that a USB port can support those being, Interrupt, Bulk, and Isochronous. Interrupt mode is more suited for devices that require very little data to be transferred between, such as computer mice or keyboards. The bulk mode is meant for devices that transfer large quantities of data occasionally such as printers and flash drives. The final mode isochronous is catered towards streaming devices that transfer data continuously and in real-time, such as sound speakers (Brain, n.d).
USB Mass Controller Device
Figure 3
Image of a USB Mass Controller
[Photo of USB Mass Controller]. (n.d.) https://www.premiumusb.com/blog/whats-inside-a-usb-drive
Next up is the USB mass controller device, and the purpose of this component is to allow the action of file transfer between the flash drive and the host computer (Sioni, 2017). It does so by providing an interface between the two that allows the flow of information to go through. Mass controller devices are the link between the host computer and the external device and provide the host computer an interface to interact with the data in the external device. Most of the time the controller automatically organizes and formats the contents in an easy to manage style that allows for ease of access. Controllers also can cease and pause operations if the need calls for it if some problem arises or if the user wishes to. However, this ability is also a possible disadvantage as if the controller were to be damaged the contents inside the device could become corrupt and lost.
Flash Memory Chip
Figure 4
Image of a Memory Chip
[Photo of Memory chip]. (n.d.) https://www.premiumusb.com/blog/whats-inside-a-usb-drive
The part that follows next is the flash memory chip, this particular one uses the NAND type logic gate as opposed to the NOR type logic gate. The difference between the two lies in their functionality, where a NOR gate will only output a 1 if both inputs are 0s a NAND gate will output 1s only when the inputs are not both zeros (NOR gate, n.d.). Flash memory chips are non-volatile meaning that even when power is not supplied to the electronic it still retains data and information, at the cost of slower performance and short lifespan compared to volatile storage methods (NOR gate, n.d.). The memory chip also serves as the main storage device and the size of it will depend on the brand and size purchased. How flash memory stores data is by converting incoming inputs into a series of 1s and 0s or binary format. These 1s and 0s are then arranged into a specific format that makes that input unique and thus its own data, otherwise known as data writing. There are also mechanisms known as a floating gate and control gate, the floating gate allows electrons to cross between control gates which determine whether or not something is a 1 or 0. The difference between a 1 and 0 is that in the 0 state an electron is blocking flow from the floating gate and control gate, and the 1 state had nothing blocking them. Since a blank EEPROM has all its gates open, that being in the 1 state, electronically erasing flash data works by inputting an electric signal and exciting electrons to free the control gates thus freeing them up and resetting them to the 1 state. (EPROM erasing time, n.d.)
Crystal Oscillator
Figure 5
Image of a Crystal Oscillator
[Photo of Crystal Oscillator]. (n.d.) https://www.premiumusb.com/blog/whats-inside-a-usb-drive
The crystal oscillator is the next component, and its main function is to help the other components keep in sync via a timed frequency generated by an internal vibrating crystal. Inside the casing, a crystal is continuously being vibrated by an electric field resulting in an electric signal being generated at a constant frequency (Crystal oscillator, n.d.). This frequency then gets converted into oscillations that help the other components of the drive keep in sync. The way the crystal is cut determines the effectiveness of the crystal oscillator, for example, high-frequency crystals are commonly cut into simple shapes such as circles and rectangles, while lower frequency crystals are cut into more complex shapes like a tuning fork. Temperature also plays a big factor in the accuracy of the oscillator as slight changes can cause the crystal to vibrate at unintended frequencies. Thus quartz is the most commonly used type of crystal nowadays as it can maintain its size and elasticity during changes in temperature and stay accurate in harsh conditions (Crystal Oscillator, n.d.).
Cover
Figure 6
Image of a typical flash drive
[Photo of USB flash drive]. (n.d.) https://www.premiumusb.com/blog/whats-inside-a-usb-drive
Finally, the cover is the part that surrounds most of the components to help secure them. The cover acts as both a protection measure and a container, as it keeps all the delicate components isolated in its environment. It prevents most things that would interfere with internal operations such as dust particulates or electrical tampering as well as helps absorb shock from accidental impacts and blunt objects. It can also act as a preservative as the cover slows the degradation of the interior components by sheltering them from environmental factors such as heat and lighting. The cover also allows the user to customize the surface of the device to their liking, by adding decorative items such as stickers and keychains. It also allows for easier storage as the cover sets a uniform standard for all devices to follow and thus pack efficiently into boxes.
Functions of a USB flash drive
Due to the nature of a flash drive, its most useful functions involve data transfer or data storage. As its memory component is a non-volatile one, it can store data for long periods of time, though in small quantities. With the invention of cloud computing the need for flash drives become increasingly obsolete as cloud storage allows for access virtually anywhere, so long as a connection to the internet is available, and hard drives pose as a more viable method of storage since the capacity of one is much larger than an average flash drive and is cheaper when comparing its price to size ratio. That said however flash drives are a compact and lightweight device that allows for access to stored files anywhere as long as a computer is available, and are more low-profile than a hard drive.
Conclusion
In conclusion, a flash drive is a relatively simple data storage device that is more convenient to carry than a hard drive and is more accessible than cloud storage. That being said however it does have its disadvantages, such as its limited storage capacity and limited accessibility compared to cloud storage, but it still does have its uses occasionally. The design of a flash drive when broken down is simple but quite complex given its size and contains a lot of delicate parts that work harmoniously together to help operate a flash drive.
References
Brain, M. (n.d.). How USB Ports Work. How USB Ports Work. Retrieved March 28, 2021, from https://computer.howstuffworks.com/usb.htm
Crystal oscillator. (n.d.). Crystal oscillator – Wikipedia. Retrieved March 28, 2021, from https://en.wikipedia.org/wiki/Crystal_oscillator#:~:text=A%20crystal%20oscillator%20is%20an,signal%20with%20a%20constant%20frequency.
EPROM. (n.d.). EPROM – Wikipedia. Retrieved March 28, 2021, from https://en.wikipedia.org/wiki/EPROM
EPROM erasing time. (n.d.). EPROM erasing time | Microchip. Retrieved March 28, 2021, from https://www.microchip.com/forums/m19434.aspx
Flash memory. (n.d.). Flash memory -Wikipedia. Retrieved March 28, 2021, from https://en.wikipedia.org/wiki/Flash_memory
NAND gate. (n.d.). NAND gate – Wikipedia. Retrieved March 28, 2021, from https://en.wikipedia.org/wiki/NAND_gate
Non-volatile memory. (n.d.). Non-volatile memory – Wikipedia. Retrieved March 28, 2021, from https://en.wikipedia.org/wiki/Non-volatile_memory
NOR gate. (n.d.). NOR gate – Wikipedia. Retrieved March 28, 2021, from https://en.wikipedia.org/wiki/NOR_gate
Sioni, N. (2017, January 12). What’s Inside A USB Drive? What’s Inside A USB Drive? Retrieved March 28, 2021, from https://www.premiumusb.com/blog/whats-inside-a-usb-drive
USB DATA TRANSFER GUIDE. (n.d.). USB DATA TRANSFER GUIDE. Retrieved March 28, 2021, from https://www.cmd-ltd.com/advice-centre/usb-chargers-and-power-modules/usb-and-power-module-product-help/usb-data-transfer-guide/#:~:text=USB%20cables%20are%20capable%20of,can%20see%20four%20metal%20strips.
USB flash drive. (n.d.). USB flash drive. Retrieved March 28, 2021, from https://en.wikipedia.org/wiki/USB_flash_drive
USB mass storage device class. (n.d.). USB mass storage device class – Wikipedia. Retrieved March 28, 2021, from https://en.wikipedia.org/wiki/USB_mass_storage_device_class
USB wiring diagram- Micro USB pinout, 7+ Images. (n.d.). USB wiring diagram- Micro USB pinout, 7+ Images. Retrieved March 28, 2021, from https://somanytech.com/usb-wiring-diagram-micro-usb-pinout-guide/
What’s Inside A USB Drive? (n.d.). What’s Inside A USB Drive? – Wikipedia. Retrieved March 28, 2021, from https://en.wikipedia.org/wiki/USB_flash_drive#History
