1.1.3 - Input, output and storage

Question 1

What is an OMR scanner?

Answer 1

OMR stands for optical mark recognition. This technology is often used to input the answers or marks that a candidate has made on a multiple choice test paper.

Question 2

What is a nfc reader?

Answer 2

Reads the data from an NFC (near field communication) tag. A common use of this technology is contactless payment in shops. Here, an NFC reader is used to read data from a bank card or mobile phone when the two devices are close to each other.

Question 3

What is a barcode?

Answer 3

A barcode is a means of representing data in a machine-readable form. Traditional barcodes represent data by using a set of parallel lines of varied width and spacing.

Question 4

What is a check digit?

Answer 4

A check digit is an extra digit or character added to the end of a long code. It is computed by applying an algorithm to the other digits. When the long code is entered, the check digit is calculated and compared to the check digit at the end of the code. If it doesn’t match, there must have been an input error. This type of validation can be carried out by software embedded within the barcode reader.

Question 5

Why are some QR codes replacing barcodes?

Answer 5

They have a higher storage capacity.

Question 6

Name 3 examples of a specialist device for people with a physical disability?

Answer 6

Sip/puff switch
Foot switch
Braille keyboard.

Question 7

What four factors should you consider when deciding on an input device?

Answer 7

Cost
Speed
Accuracy
Reliability

Question 8

What is a biometric?

Answer 8

A biometric is a physical characteristic such as fingerprints, facial images, irises, and voice. Improvements in technology have made the use of biometric scanners increasingly common, as recognition techniques have become more and more reliable

Question 9

Where are biometrics used?

Answer 9

Fingerprint recognition is often used to access phones and computers and to authorise small payments. Many airports are now using iris recognition as a major part of their security systems.

An emerging use of biometrics is that of voice recognition. Our voices have unique characteristics, such as length of the vocal tract, pitch, and accent. Many banks and insurance companies now use voice recognition to identify customers.

Question 10

Why are biometrics dangerous?

Answer 10

Biometric spoofing can be used to fool biometrics, e.g using voice recording or copies of fingerprints.
Additionally, there is a danger that users’ biometric data can be handled unlawfully and even sold.

Question 11

What does secondary storage need to do?

Answer 11

It needs to be high capacity and low cost, fast enough for loading and saving files, and reliable enough to provide permanent, non-corruptible storage.

Question 12

Rank the common storage devices by storage capacity.

Answer 12

Magnetic hard disk(1000GB), SSD(256), Blue-Ray(25), DVD(4.7), CD(0.7)

Question 13

What are the advantages of an HDD?

Answer 13

It’s capacity and cost - currently it offers great capacity at a lower cost than SSDs. So, it is best suited to desktops and laptops where low purchase cost is the most important consideration.

Question 14

What are the disadvantages of an HDD?

Answer 14

It has slower access speeds (between 80 and 200MB/s), has moving parts so is more prone to damage, and is prone to fragmentation.

Question 15

What are the advantages of an SSD?

Answer 15

Access speeds are between 200-500MB/s, always outperforming magnetic and optical drives.
The absence of moving parts also means that mechanical failure is unlikely, and reduces the heat generated by a computer system.

Question 16

What are the disadvantages of an SSD?

Answer 16

SSD storage is more expensive per GB than magnetic storage.
An SSD has a limited lifespan - the number of times it can be written to is finite, and cells can leak if devices are not powered up from time to time.

Question 17

What are the uses of an SSD?

Answer 17

SSDs are particularly useful for storing frequently read/changed files.
Having your OS on an SSD will dramatically improve the time for your system to boot.
If there are commonly accessed apps and data, it may be wise to store these on SSDs also.

Question 18

What is increasingly common on computers?

Answer 18

Storing the OS and files on an SSD for quick access, and less used files on a magnetic HDD for cheap storage.

Question 19

What are CD/DVD-ROMs?

Answer 19

These devices are read only memory, normally mass-produced for music and films.
They are light and easily transported and stored, however high speed broadband and cloud distribution mean software is now normally distributed via the internet.

Question 20

What are CD/DVD-R?

Answer 20

R stands for “recordable”. These type of discs were once popular for archiving photos.

Question 21

What are CD/DVD RW?

Answer 21

R stands for “rewritable”. This disc type was popular for backing up files - making a temporary copy. However, today most systems are backed up to high speed digital tape or cloud storage.

Question 22

What is the problem with optical discs?

Answer 22

They are susceptible to scratching and exposure to heat may cause the polycarbonate or metallic layers to warp. Light can damage the chemical dyes that coat many optical discs.
The biggest problem is the availability of drives to read them.

Question 23

What is virtual storage?

Answer 23

Virtual storage is storage that is not installed as part of a user’s own computer system.

Question 24

What is NAS?

Answer 24

Network attached storage is usually provided in the form of a dedicated device installed as part of a LAN. There are small devices for home networks, and much larger ones for business use. The user will see the drive listed alongside their local storage.
They will lose access in the event of network failure.

Question 25

What is cloud storage?

Answer 25

Cloud storage is facilitated by the internet, and is usually owned and managed by commercial organisations.
A popular business model, at the time of writing, is to provide a certain amount of cloud storage (typically 1GB) free of charge, and then to charge per GB for additional storage needs.

Question 26

What has cloud storage impacted the most?

Answer 26

Cloud storage has had a huge impact on the way that we store files, and the way that we move data between devices. In particular, it has affected the market for portable storage devices such as optical discs and USB flash drives. Nowadays, it is quite rare to get an optical disc drive as standard when you buy a desktop or laptop computer

Question 27

How can cloud storage be configured?

Answer 27

They can be configured to automatically sync with local drives, meaning there is always a local copy in case there is no available internet connection.
Any changes made locally will be synchronised when the connection is next available.

Question 28

What does the RAM hold?

Answer 28

The RAM inside a computer holds all of the data and instructions currently being processed. For any program to be executed, it must first be loaded into the RAM, because RAM has quicker read and write speeds.

Question 29

How is memory within RAM split up?

Answer 29

Within the RAM, the memory is split up into separate locations, each given a unique memory address which the processor uses to access it.

Question 30

Why is RAM called random access memory?

Answer 30

Any of the locations in RAM can be accessed in the same amount of time, unlike other storage devices where a sensor (like a read/write head) needs to be moved into place.

Question 31

Give a summary of RAM’s characteristics.

Answer 31

It is volatile (requires power to hold data)
You can read and write to it
It is quicker to access than secondary storage
It has the largest capacity of all main memory.

Question 32

What does the ROM hold?

Answer 32

ROM is typically used to store the boot sequence (BIOS) for a computer.
Unlike RAM, it is non-volatile and will not lose its data when the power is switched off. The contents of ROM are set by the computer manufacturer and, as the name implies, your computer usually only reads from it.
Which is good because it is crucial to your computer system and any changes you make could stop the computer booting up properly.

Question 33

What is the BIOS?

Answer 33

The BIOS (Basic Input/Output System) stored on ROM is a very limited sequence of instructions that checks that the core components of the computer system (RAM, fundamental input/output devices, secondary storage) are connected and responding correctly.

Question 34

What does the boot sequence do once done?

Answer 34

It loads the essential parts of the main operating system from secondary storage into RAM.
From this point, the operating system will oversee the operation of the computer, managing memory, storage, and requests for input/output.

Question 35

What is virtual memory?

Answer 35

Virtual memory is a way a computer system can compensate for a shortage of RAM.
Modern applications often have high main memory requirements, and running such applications on systems with minimal main memory will lead to lag as applications compete for RAM access.

Question 36

How does virtual memory work?

Answer 36

When virtual memory is required, the operating system creates a set of virtual addresses in secondary storage. Data moved to virtual memory is stored as pages.
When the processor is ready to accept instructions from the files in virtual memory, it moves the page files into RAM and allocates a physical address to the data.
Other data is moved from RAM to virtual memory or secondary storage.

Question 37

Are HDDs or SSDs better for virtual memory?

Answer 37

SSDs have an advantage over HDDS because access speed is closer to that of RAM.
However, using SSDs regularly for virtual memory reduces their lifespan because of their finite read/write lifecycle.

Question 38

What is flash memory?

Answer 38

Some microcontrollers use a memory chip to store instructions called flash memory. This is non-volatile, and can be written to and read from.
Microcontrollers and microprocessors often only have a single program to run, so they can be stored and fetched from the same place as there is no need for multiple programs to share the same main memory.
This means flash is used as storage and main memory.