1.1.3 Input, output and storage

What you need to know

(a) How different input, output and storage devices can be applied to the solution of different problems.

(b) The uses of magnetic, flash and optical storage devices.

(d) Virtual storage.

What are input, output, and storage devices?

All computing systems can be broken down into a basic input, processing, output, and storage model (diagram on the right)

Hardware input devices such as keyboards, scanners or microphones, are used to input data that is processed by software programs (such as editing applications); hardware output devices such as printers or screens are used to output the processed data. External storage devices are used to provide additional memory, backup, or security for the long-term storage of data such as files, photos, videos.

A computer system will almost always need to communicate with other computer systems/ people and will require an effective way of storing data.

Hardware: the physical parts of a computer system
Software: instructions/programs that enable the hardware to work usefully, fulfilling an end user’s requirements

Examples of input devices:

Keyboard (button press --> binary --> character set --> output)

Used for manual data entry
onscreen (using a touchscreen)

Mouse (sensor/button press --> change in x/y direction on screen/selections)

Used to select different options on a screen

Webcam (light sensor --> data stream --> output)

Used to transmit live video for video chats
Used to monitor rooms (e.g. in factories, offices, classrooms)

Touchscreen (electrostatic grid --> changes in current detected)

Used where a mouse/keyboard would be too large or vulnerable (e.g. smartphones, tourist information points)

Barcode scanner (light/laser --> waveforms detected from reflection of light)

Used in shops to identify particular items

Microphone (audio sensor --> data stream)

Used to transmit audio for use in calls or monitoring

Examples of output devices:

Speakers (data stream --> amplified audio)

Used to provide audio information (e.g. at tourist information points)
Used to play music

Monitor, Visual Display Unit (data stream --> imagine produced on monitor)

Displays the user interface of the device
Used to provide visual information (e.g. displaying programs on a laptop)

Motor (interprets program outputs -->movements)

Used for specific, physical operations (e.g. in factories)

Printer (data --> inkjet/laser)

Used to provide hard-copies of information (e.g. in offices)

Types of storage devices

Magnetic:

Advantages

High data transfer rate
Non-volatile
Large capacities

Disadvantages

Not portable – contains moving parts that may break if moved
Can be noisy

Solid:

Advantages

Non-volatile
Contain no moving parts (solid-state – unlikely to break and hence portable); electrical impulses are used to imprint data
Used to transport data light and robust
High transfer rate

Disadvantages

Degrades over time
Expensive to produce and hence only available with small capacities

E.g. SD cards, USB sticks, ROM)

Optical:

E.g. CD-ROM – data is written during the manufacturing process

E.g. CD-R/ DVD-R – data can be written by the user but only once

E.g. CD-RW/DVD-RW- data can be written and rewritten by the user

Advantages

Cheaper than most forms of storage
Non-volatile
Moderate capacity
Disks are light and portable

Disadvantages

Slow data transfer rate
Disks can easily scratch

Research task

Complete the following table using the link - CLICK HERE (you will need to download the table if your teacher has not provided in your Google Classroom)

RAM and ROM

Random Access Memory (RAM)

RAM is a type of very fast memory that is used to temporarily hold data about currently running programs. When you load any file from the hard drive there is a lag between the request and the data being sent, this would cause a massive slow down of the CPU if data was constantly being requested from the hard drive. Instead, a single request is sent to the hard drive when the program loads and the whole program is loaded into RAM.

The RAM is electronic memory and all the data is stored. This means that there is very little latency and there the computer loads the program much faster than if it wasn’t used.

However because RAM data is stored electronically, RAM is volatile – once power is lost all data is lost as well.

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Read Only Memory (ROM)

Read-only memory is mainly used in a PC to store the tiny mini operating system called the BIOS. The BIOS data is flashed to the ROM chip when the motherboard is made and does not change for it’s entire lifetime (hence the term Read-Only). If you want to update the BIOS, you need to flash the ROM chip.

The BIOS is responsible for doing a system hardware check before the system starts to make sure all the connected devices are functioning. Once it has completed the check it boots up the operating system.

Basic Input Output Systems

Virtual Storage

With ever-increasing bandwidth capabilities becoming popular via fibre optics and wireless 4G and 5G, companies and individuals are increasingly turning to virtual storage.

“The concept of storing and retrieving data over the internet in the cloud instead of a local storage device.”

Advantages:

- Data can be accessed at any time, from any device, as long as there is internet access.
- Data can be easily shared without the need for removable media transfer e.g. USB stick.
- Easy to collaborate.
- Storage is considered to be limitless from the users point of view.

Disadvantages:

- Can become expensive.
- If connections are poor, access times can be slow.
- No internet connection means no access to your files.

Virtual storage data houses:

Although virtual storage is thought of as storing data “in the cloud” - your data is actually stored on physical, permanent storage media in a remote location.

Logical vs physical storage:

Virtual storage can also refer to the abstraction or separation of logical storage from physical storage.
A common misconception is that a single storage area is neatly structured and organised under a single drive. This is known as logical data storage whereas physical storage can be implemented by the possibility of your folders, files and associated data stored across different media's such as:
- - Magnetic hard disks.
  - Solid-state drives.
  - Network file servers.
  - Cloud storage.

PAST PAPER QUESTIONS

Try and answer the past paper exam questions -You can write your answers on paper or print out the exam paper - Mark Scheme is provided at the end of the paper questions. (try not to look at the answers before attempting all questions)

Question_Topics_-_1.1.3_Input_output_and_storage.pdf

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