Storage devices and media Cambridge IGCSE Information & Communication Technology revision
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In plain words
Storage is where data lives when the computer is switched off. The device is the machine that reads and writes. The medium is the thing the data is held on. A DVD drive is a device, and the DVD is the medium.
5 things to know
- Magnetic storage: fixed and portable hard disk drives hold very large amounts for a low cost, and are used to store the operating system, software and files. They have moving parts, so they can be damaged by knocks. Magnetic tape holds huge amounts cheaply and is used for backups, but it is slow, because data must be read in order (serial access).
- Optical storage: CDs, DVDs and Blu-ray discs are read by a laser. They are cheap and portable, but hold less than a hard disk and are easily scratched. A Blu-ray disc holds the most, then a DVD, then a CD.
- Solid-state storage: solid-state drives (SSD), pen drives and memory cards (SD, xD, CFast) have no moving parts. They are fast, robust, small and use little power, but cost more for each gigabyte.
- Memory cards are used in cameras and phones. Pen drives are used to carry files between computers.
- Direct access means any item of data can be reached straight away, as on a disk or solid-state drive. Serial access means data must be read through from the start, as on tape.
Worked example
A company wants to back up all of its data every night and keep the copies for years. Which storage is suitable, and why?
- The amount of data is very large, and the copies are rarely read.
- Magnetic tape holds huge amounts at a very low cost.
- Its slow, serial access does not matter for a backup that is only read if something goes wrong.
Tips and tricks
- Give the reason with the choice: capacity, cost, speed, portability or robustness.
- Media and devices are different things in this syllabus. If asked for a medium, name the disc, tape or card, not the drive.
It lands in your notebook with its questions as flashcards.
Storage devices and media: 5 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
Which storage device has no moving parts?
That makes it fast and robust.
Which optical disc holds the most data?
It uses a blue laser to read smaller marks.
Which storage would be used in a digital camera?
It is small, robust and easily removed.
What is serial access?
Magnetic tape works this way.
Which is an advantage of a magnetic hard disk drive?
It is cheaper for each gigabyte than solid-state storage.
Quiz
5 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
2 questions, 4 marks. Write your answers on paper, then check them.
Storage devices and media
Cambridge IGCSE Information & Communication Technology 0417 · 4 marks · papermunch.org
Name ______________________________ Date ______________
Give two advantages of a solid-state drive compared with a magnetic hard disk drive.[2]
Show answerHide answer
It has no moving parts, so it is more robust. It reads and writes data faster. (Also: it is lighter and uses less power.)
Explain why magnetic tape is suitable for backups but not for everyday use.[2]
Show answerHide answer
It stores very large amounts of data cheaply. But access is serial, so finding one file is slow.
Answers: Storage devices and media
- 1. It has no moving parts, so it is more robust. It reads and writes data faster. (Also: it is lighter and uses less power.)
- 2. It stores very large amounts of data cheaply. But access is serial, so finding one file is slow.