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computer science

USB flash drive

USB flash drive is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand USB flash drive rather than just read about it. In short: A USB flash drive (also known as a thumb drive) is a data storage device that includes flash memory with an integrated USB interface. A typical USB drive is removable, rewritable, and smaller than an optical disc, and usually weighs less than 30 g (1 oz).

USB flash drive — main illustration
USB flash drive — illustration

Key takeaways

  • USB flash drive belongs to computer science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect USB flash drive to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of USB flash drive from memory before moving on to harder problems.

Reference excerpt

A USB flash drive (also known as a thumb drive) is a data storage device that includes flash memory with an integrated USB interface. A typical USB drive is removable, rewritable, and smaller than an optical disc, and usually weighs less than 30 g (1 oz). Since first offered for sale in late 2000, the storage capacities of USB drives have ranged from 8 megabytes to 1 terabyte (TB). As of 2024, 4 TB flash drives were the largest currently in production. Some allow up to 100,000 write/erase cycles, depending on the exact type of memory chip used, and are thought to physically last between 10 and 100 years under normal circumstances (shelf storage time). Common uses of USB flash drives are for storage, supplementary back-ups, and transferring of computer files. Compared with floppy disks or CDs, they are smaller, faster, have significantly more capacity, and are more durable due to a lack of moving parts. Additionally, they are less vulnerable to electromagnetic interference than floppy disks, and are unharmed by surface scratches (unlike CDs). However, as with any flash storage, data loss from bit leaking due to prolonged lack of electrical power and the possibility of spontaneous controller failure due to poor manufacturing could make it unsuitable for long-term archiving of data. The ability to retain data is affected by the controller's firmware, internal data redundancy, and error correction algorithms. Until about 2005, most desktop and laptop computers were supplied with floppy disk drives in addition to USB ports, but floppy disk drives became obsolete after widespread adoption of USB ports and the larger USB drive capacity compared to the "1.44 megabyte" 3.5-inch floppy disk. USB flash drives use the USB mass storage device class standard, supported natively by modern operating systems such as Windows, Linux, macOS and other Unix-like systems, as well as many BIOS boot ROMs. USB drives with USB 2.0 support can store more data and transfer faster than much larger optical disc drives like CD-RW or DVD-RW drives and can be read by many other systems such as the Xbox One, PlayStation 4, DVD players, automobile entertainment systems, and in a number of handheld devices such as smartphones and tablet computers, though the electronically similar SD card is better suited for those devices, due to their standardized form factor, which allows the card to be housed inside a device without protruding. A flash drive consists of a small printed circuit board carrying the circuit elements and a USB connector, insulated electrically and protected inside a plastic, metal, or rubberized case, which can be carried in a pocket or on a key chain, for example. Some are equipped with an I/O indication LED that lights up or blinks upon access. The USB connector may be protected by a removable cap or by retracting into the body of the drive, although it is not likely to be damaged if unprotected. Most flash drives use a standard Type-A USB connection allowing connection with a port on a personal computer, but drives for other interfaces also exist (e.g. micro-USB and USB-C ports). USB flash drives draw power from the computer via the USB connection. Some devices combine the functionality of a portable media player with USB flash storage; they require a battery only when used to play music on the go.

History The basis for USB flash drives is flash memory, a type of floating-gate semiconductor memory invented by Fujio Masuoka in the early 1980s. Flash memory uses floating-gate MOSFET transistors as memory cells. In 1995, a group of companies including IBM, Microsoft, Intel and NEC were working on the development of Universal Serial Bus (USB). Multiple individuals have staked a claim to having invented the USB flash drive. On April 5, 1999, Amir Ban, Dov Moran, and Oron Ogdan of M-Systems, an Israeli company, filed a patent application entitled "Architecture for a Universal Serial Bus-Based PC Flash Disk" that combined flash memory storage with USB connectors through a USB controller. The patent was subsequently granted on November 14, 2000, and these individuals have often been recognized as the inventors of the USB flash drive. Also in 1999, Shimon Shmueli, an engineer at IBM, submitted an invention disclosure asserting that he had invented the USB flash drive. Netac Technology filed a patent application for its USB storage device on November 14, 1999, and was granted by the Chinese government in July 2002. Netac went on to obtain another patent in the United States on October 13, 2000, and application was granted on December 7, 2004. Netac's patent was disputed by M-systems and Singaporean company Trek 2000 but Netac remained as the holder of the patent. Netac went on to file legal battles domestically in China and overseas and had received patent royalties and licensing fees in return. The company also invented a feature called "write-protect" function on its USB memory sticks. A Singaporean company named Trek 2000 International is the first company known to have sold a USB flash drive, which it trademarked as "ThumbDrive", and has also maintained that it is the original inventor of the device. Trek 2000 obtained a Singapore patent for the "ThumbDrive" in April 2002. It went on to sue the other four companies for infringing its patent. Singapore High Court ruled in Trek 2000's favour in 2005. After that, Trek 2000 went on to obtain patents from other countries. However, in 2005, Trek 2000 experienced a setback when its USB storage device patent was revoked in the United Kingdom. Pua Khein-Seng, a Malaysian engineer who co-founded a Taiwanese company named Phison, invented a USB drive system on a chip (SoC) design in 2001 which uses a single chip instead of multiple chips used by its competitors, which reduces the size and cost of production of flash drives. Given these competing inventor claims, patent disputes involving the USB flash drive have arisen over the years. Both Trek 2000 International and Netac Technology have accused others of infringing their patents on the USB flash drive. However, the question of who was the first to invent the USB flash drive has multiple claims persists. Netac Technology got the basic American copyright on December 7, 2004. And in the lawsuit, the PNY company paid 7.71 million dollars to Netac.

… excerpt ends here. Continue reading the full article.

Illustrations

USB flash drive: A SanDisk Cruzer USB drive from 2011, with 4 GB of storage capacity
A SanDisk Cruzer USB drive from 2011, with 4 GB of storage capacity
USB flash drive: A SanDisk Ultra Flair USB drive from 2020, attached to an HP laptop
A SanDisk Ultra Flair USB drive from 2020, attached to an HP laptop
USB flash drive: Transcend JetFlash from 2014
Transcend JetFlash from 2014
USB flash drive: SanDisk 1 TB USB-C flash drive (2020 model) next to a 50 cent euro coin
SanDisk 1 TB USB-C flash drive (2020 model) next to a 50 cent euro coin
USB flash drive illustration

Worked examples

Example 1 — a first encounter with USB flash drive

Start with the simplest possible case. Write down what USB flash drive claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to USB flash drive before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about USB flash drive ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of USB flash drive

In research
USB flash drive appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses USB flash drive in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
USB flash drive is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2000 in computing, 2000 in technology, Computer-related introductions in 2000, so understanding it makes those chapters shorter.
In everyday life
Look for USB flash drive outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study USB flash drive in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what USB flash drive means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain USB flash drive out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is USB flash drive in simple terms?

A USB flash drive (also known as a thumb drive) is a data storage device that includes flash memory with an integrated USB interface. A typical USB drive is removable, rewritable, and smaller than an optical disc, and usually weighs less than 30 g (1 oz).

Why does USB flash drive matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study USB flash drive?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on USB flash drive.

Tags

  • 2000 in computing
  • 2000 in technology
  • Computer-related introductions in 2000
  • Office equipment
  • Solid-state computer storage
  • Taiwanese inventions
  • USB

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