Digital Devices in IT systems 1-14 Flashcards
Multifunctional Devices
These devices can perform multiple functions such as inputting or outputting data
Personal computers
These are small and inexpensive computers for use of individual users
Mobile devices
Smartphones and tablets are made with portability in mind
Entertainment Systems
These devices for watching TV/films
Digital Cameras
These capture images and videos digitally using and image sensor and store them as digital data
Navigation System
These devices uses a GPS (Global Positioning Satellite) receiver to locate the user’s position on a digital map and provide
Communication devices and systems
These devices can send and receive analogue or digital data to and from another device
Data capture and collection systems
These devices collect and input data through automated systems rather than direct data entry
Uses of digital devices
Education and training
Creative
Personal
Social
Retail
Organizational Use
Input devices
Keyboard - Made up of keys used to input alphanumeric characters and symbols
Mouse - A pointing device used to select items on screen
Scanner - Converts Hard copy text or images into a digital format
Graphics Tablet - Controls the computer using a stylus on a tablet
Microphone - Converts analogue signals into electrical signals to be sent to the sound card which converts
analogue to digital
Output devices
Monitor - Outputs an image to the user, e.g. of the user interface, a photo or a document
Projector - Outputs an image onto a wall or screen
Devices for accessibility
Trackball - an easier-to-use alternative to a mouse, consisting of a moveable ball on a base
Touch-screen - useful for people unable to use a keyboard easily
Eye motion sensors and head motion trackers - used by people with significantly limited mobility
Braille embosser - a type of printer that outputs text as braille cells
Biometric readers
Read fingerprints, hand prints, or irises for use in personnel identification systems
Barcode readers
Read lines of different thickness and convert them into a string of values
Optical Mark recognition (OMR)
Readers automatically read a form and input the data
Smart meters
Accurately record electricity and gas usage and send readings into the energy supplier
Radio-frequency identification (RFID)
Devices are used in stocktaking and race timing systems
Hard Disk Drives
Magnetic storage devices, commonly used as the primary internal storage device but can be external.
Benefits of Hard Disk Drives
- Large Storage capacity
- Low Cost on a per byte basis
- Very reliable
Downsides of Hard Disk Drives
- Slower than SSDs at loading data
- External HDDs are not as portable as some other options
Solid state drives
Flash memory devices commonly used as the primary storage in portable computing devices like tablets and laptops
Benefits of Solid state drives
- Very fast data read/write speeds
- Low power consumption
- Extremely reliable as they have no moving parts which can be damaged
Downsides of Solid state drives
- Higher cost than HDDs on a per byte basis
- Usually have a lower storage capacity
- Only have a finite number of writes
SD cards
Small flash memory cards that are commonly used for storage in digital cameras and some smartphones
Benefits of SD cards
- Very small and portable
- Easy to transfer between devices with SD card readers
Downsides of SD cards
- Very small storage capacity, generally around 64gb - greater capacity is costly
- Various ‘enhancements’ to the standards resulting in potential compatibility problems, for example SDHC and SDXC
USB memory sticks
Small flash memory devices that connect through a USB port
Benefits of USB memory sticks
- Extremely portable devices
Downsides of USB memory sticks
- Storage capacity is low when compared to SSDs and HDDs
- Only have a finite number of writes before they break
Optical disks
Such as CDs, DVDs and Blu-ray disks are used for software, music and movies
Benefits of Optical disks
- Small and portable
-A lot of devices have built in capability to read optical discs, with external devices being inexpensive if needed
Downsides of Optical Disks
- Archival stability of writable media can be questionable
- Fragile and easy to damage
Magnetic Tape
Used for large data backups
Benefits of Magnetic Tape
- Very large storage capacity
- Very cheap on per byte basis
Downsides of Magnetic tape
- Data is accessed serially which is very slow
-Requires specialist equipment for recording and reading data
Operating Systems
Coordinates all the operations of your computer. It manages all the recourses on the computer, such as the CPU and RAM, and controls the software and hardware. Without it, your PC would be useless
Real-time operating system (RTOS)
Inputs are processed and responded to instantaneously
Provides fast responses and is best used for traffic lights and air traffic control systems
Single-user single task operating systems
One user can use the system at a time, and one application can run at a time
Requires fewer resources and is best used on devices that have limited processing and memory
Single-user multitasking operating systems
One user can use the system at a time, but many applications can run simultaneously
Allows the user to use several applications at once
Best used on systems where a user needs to be able to switch quickly between applications
Multi-user operating systems
Many users can use the system at the same time and can run many applications simultaneously
Processing and resources can be shared by multiple-users
Best used where many users need access to the same processing or resources at the same time
Role of operating systems
A digital device is that link between the hardware and the software. It passes messages back and fourth and carries out instructions from the software to the hardware
Networking
Operating systems simplify networking in a computer. The operating system implements a number of networking technologies such as
- the TCP/IP stack
- network utility programs such as traceroute
- device drivers for the network interface card
Security
A number of features are commonly built into operating systems to help improve security
- User authentication
- Antivirus and firewall software
- Backup facilities
Memory management
The operating system manages the computer’s resources, such as its memory
To do this, the operating system decides and tracks
- which processes to allocate memory to
- how much memory to allocate to each process
- when to un-allocate memory
- transferring data to the pagefile (or swapfile) on the HDD temporarily to free RAM
Multitasking
Most operating systems allow you to run more than one application simultaneously. To do this, the operating system, must be able to allocate resources to each application in order to allow it to complete two or more tasks.
Device drivers
AN operating system comes with generic device drivers that work with a wide variety of different peripheral devices, allowing them to communicate with your computer
Command line interface (CLI)
The user interacts with the computer by typing in commands in response to prompts displayed on the screen
Benefits of CLI
- Experienced users to find quicker to complete tasks
- Requires far less memory and processing power than GUis to run
Downsides of CLI
- Requires knowledge of the specific commands for performing functions
- Learning so many commands can be intimidating for inexperienced users
Graphical user interface (GUI)
Users interact with the device by controlling a pointer or touch screen to select icons and menus displayed on screen. GUIs are widely used on devices from PCs to smartphones
Benefits of GUI
- This simple, intuitive method of interacting is easy for beginners to use
- It doesn’t require users to learn any commands to perform tasks
-There are usually options to adapt the interface according to an individual user’s needs, for example by using screen magnifiers or changing the colors or font sizes
Downsides of GUI
- It is often resource intensive, requiring a lot of processor power and memory
- Experienced users can find it frustrating to complete tasks they could perform in a CLI with one command
Menu-based interface (MBI)
Users interact using a simple menu that presents options to choose from. AN example is an ATM screen
Benefits of MBI
- The limited number of options makes it easy to use
- It is often possible to figure out how to perform tasks without any instruction
- They can include options to adapt the interface for an individual user’s needs, for example by providing speech output or a choice of larger font size
Downsides of MBI
- Performing tasks can be slow and frustrating where many levels of options must be traversed
Utility Software
Used to manage system resources. Utilities are like a tool box to help us optimize and maintain our computer system. Many are pre-installed as part of the operating system
Disk Utilities
Designed to maintain the performance of a computer’s disk drive
File compressors
Backing up very large files and sharing them online can be difficult
This utility compresses files to reduce their size and decompresses them for later access
Backup
You regularly want to back up your files, but this can be slow as a manual process. Backup utilities allow you to automate the backup process
Disk defragmenter
Over time a computer’s disk drive becomes fragmented, which slows down file access. This utility reorganizes the data for quicker access, but is only required on a HDD when using Windows file systems
Network utilities
Designed to maintain good network traffic and keep network secure
Firewall
Open networks are at risk from threats like hackers and worms. Firewalls prevent unauthorized traffic
Antivirus
Prevents computers from receiving viruses and detects and removes viruses that have already infected the system
File types
Different file types are used to denote the form, or structure, of the data stored within the file. The file extension tells the user what type of data the file should contain
Image file types
GIF - small file size but low quality due to limited number of colors
JPG - good compression, although compression is lossy so files cannot be decompressed
PNG - uses lossless compression to save high quality images in a low file size
BMP - an uncompressed file format, so image quality is extremely high but file size is very large
Video file types
MKV - supports high-quality video playback but is not well supported by some devices
MOV - designed for use with Apple QuickTime software, but can be played using other software
MP4 - supports high-quality video while still compressing file size
AVI - uncompressed so is very high quality but very large file size
Application software file types
DOC and RTF - commonly used file formats for documents created using word processing software
PDF - a format that represents data independently of the originating software and/or hardware
Application Software
Allows end users to complete tasks, such as creating a report or a presentation
Productivity software
These are applications like word processors , desktop publishers and spreadsheets that are used in office environments to support business tasks and improve efficiency
Graphics software
These applications are used to edit photos or create original artwork
Communications software
These applications make communicating quicker and easier. They include instant messaging, email and VOIP software
Proprietary software
The source code is privately owned by the software company
Benefits of Proprietary
- Support (e.g for setup and troubleshooting) is provided by the software creators
- It may have more features than open source software
Downsides of Proprietary
- The software company may be slow to provide updates and bug fixes
- Software is usually very generic, with little scope for customization due to copyright or complexity issues
- It can be costly
Open source software
The source code is available to read and modify
Benefits of Open source
- Most open source software is free to use, although many companies provide paid-for services to enhance and/or support open source
- Support and fixes are provided by the community, often via forums
- Open source utility software is usually compatible with other proprietary utility software
Downsides of Open source
- Support with fast response may not be available when needed, as it relies on goodwill
- There may be indirect costs involved in paying for support and training
