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Topic 1.2 : Features of digital devices
Topic 1.2 : Features of digital devices
Topic 1.2 : Features of digital devices
Students should describe, explain, distinguish and compare between features of digital devices (portability, performance, storage, user interface, connectivity, media support, energy consumption, expansion capability, security features, applications);and multi-functional devices.
To memorize: PP SU CM EcExS
Features of digital devices
Features of digital devices
The digital devices that you use have a number of features, such as portability, performance and connectivity. Different devices will have different features.
1. Portability
1. Portability
For a device to be portable, it needs to be easy to carry and move around. This means that the portability of a device is directly related to its size and weight.
For some devices, such as a television or a desktop computer, portability is unlikely to be a priority.
2. Performance
2. Performance
A high-performance device performs its job or tasks quickly. The speed at which a device performs is determined by the speed at which it can carry out instructions from its software. Software instructions are carried out by the processor, which means that a faster processor will increase performance (see page 62).
Instructions are loaded into the processor from RAM, which means that faster RAM will also allow instructions to be loaded into the processor more quickly.
RAM holds all software instructions to be carried out, so more RAM will allow the system to have more programs running at the same time. In addition, because instructions are loaded into RAM from storage, such as a hard disk (see page 39), faster storage will enable faster loading of instructions to RAM.
When the space in RAM runs out, storage is used as an overflow, and this is known as virtual memory (see page 60). This means that fast storage means faster access to instructions in virtual memory.
The software itself can also be written in an efficient way that makes the most of the processor’s capabilities. Inefficient software can slow down the whole system and therefore has an impact on a device’s performance.
3. Storage
3. Storage
For a device to be portable, it needs to be easy to carry and move around. This means that the portability of a device is directly related to its size and weight.
For some devices, such as a television or a desktop computer, portability is unlikely to be a priority.
4. User interface
4. User interface
Users give commands to a device through the user interface. There are several different types of user interface.
COMMAN D LINE INTERFACE (CLI)
When using a command line interface, users enter text instructions and the computer system provides results or feedback as text. This type of interface is often found on older systems or for devices with limited storage because it requires little memory.
Commands have to be typed precisely because the interface only recognises certain commands. There is usually a help menu for users that lists and explains the acceptable commands.
MENU-D RIVEN INTERFACE
This type of interface displays a list of options as a menu. Selecting one of these options will either trigger a command or display another menu with further options to choose from.
Menu-driven interfaces are easier to use than command line interfaces, but can take more time as you have to go through the menu structure each time you want to carry out a command, rather than typing the command directly into the system.
This type of interface is used in many devices including ATMs (cash machines in banking), televisions and older mobile phones.
GRAPHICAL USER INTERFACE (GUI)
A graphical user interface is controlled by a pointer on the screen and uses a screen made up of windows, icons and menus.
◾◾ Windows are areas of the screen that are dedicated to applications or operating system tasks.
◾◾ Icons are small images that represent an application. They can be selected with the pointer to open the application.
◾◾ Menus provide options for tasks relating to the operating system or open application.
This is the easiest type of interface to use, but it takes up more memory and storage than a command line or menu-driven interface.
VOICE INTERFACE
A voice interface allows the user to give spoken commands to a device. The device has voice recognition software which matches the spoken words against a library of words to find a match. To save storage on the device, the library of words is often stored online, so these devices usually require internet access.
The disadvantage of using a voice interface is that sometimes the software cannot find a match or returns an incorrect match, which produces unwanted results. For this reason, voice interfaces sometimes check the instruction with the user before searching for a match. Some voice interfaces use the results of this confirmation to ‘learn’ the voice of their user and improve future matches.
The advantage of voice interfaces is that hands-free operation is possible. This means that they are often used in vehicles in order to improve road safety.
GESTURE INTERFACE
This type of interface allows the user to control the device by swiping their finger or fingers across the screen, or by pinching their fingers together to zoom in or out. This type of interface is commonly found on devices with touch screens.
5. Connectivity
5. Connectivity
Devices can share data by connecting to each other using wired or wireless connectivity. Connectivity can be used to update software, back up files or play media from one device on another. Different connectivity types provide different speeds of data transfer and levels of convenience. Wired connectivity is usually faster and more reliable, but introduces additional cost, mess, inconvenience and safety risks such as tripping, especially for young children.
You will learn more about connectivity types in Unit 2 Connectivity (pages 71–76).
6. media support
6. media support
Different devices can read data from and write data to different types of
media. Examples of media include SD and microSD flash memory cards, and
DVD. If devices do not have built-in (native) media, adapters can usually be
connected to provide connectivity to an external device into which the media
can be inserted.
7. energy consumption
7. energy consumption
Digital devices require electricity to work. One benefit of lower energy consumption in mobile devices is a longer battery life. Due to the rising cost of energy and pressure from customers and governments to be more environmentally responsible, manufacturers are creating digital devices that consume less energy. The aim of this is to save their customers money and demonstrate social responsibility, such as by reducing environmental damage.
You will learn more about sustainability in Unit 3 Operating online (page 153)
8. expansion capability
8. expansion capability
Some PCs allow users to install additional components. Some smartphones and tablet devices have expansion slots to allow them to make use of flash memory cards (see page 19). Systems can also be expanded using ports such as USB ports. These allow the user to connect extra devices called peripheral devices (pages 21–41).
9. security features
9. security features
The data stored on digital devices may be private, valuable or both. This means that devices need to have security features to keep their users’ data safe.
SOFTWARE SECURITY
To prevent unauthorised access to data, digital devices have a range of software security features to ensure that the person trying to use the device is allowed to do so.
The operating systems of many devices can be set so that, when the device is turned on, the user must enter a password or personal identification number (PIN) before the device can be used. Another common security setting locks the device’s screen or keyboard if it has not been used for a specified period of time, after which the password or PIN will be required to unlock it again. Some devices are set so that, if an incorrect password or PIN is entered, the user must wait a set amount of time before trying again. Such systems may even wipe the data after only a few failed attempts. This prevents criminals from freely guessing thousands of combinations in order to break into the device or system.
The longer and more complex a password is, the better it is. Pattern PINs are used by some smartphone operating systems, and they allow the user to set a swipe pattern between a group of points. A four-digit pattern PIN is more secure than a four-digit PIN, because it has 389,112 possible combinations, whereas the four-digit PIN has 10,000 possible combinations.
Some devices use biometric scanners, such as Apple® Touch ID®1, to provide authorised users access to data on that device (see page 27 for more about biometric scanners).
You will learn more about passwords, PINs and other ways to secure data in Unit 3 Operating online (page 100).
PHYSICAL SECURITY
Physical security to prevent theft is also important. Many devices use security slots which can have locks attached to secure them to furniture. Some attach to specialist slots. Others connect to a port on the device with special screws used to secure the locks in place. Figure 1.33 shows an example of a security lock.
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