Studied by 8 people
what are mainframe computers and what are they used for?
Used by large companies (banks, utility companies etc) for complex processing tasks.
Large powerful computers that can carry out many different tasks for many different people at the same time.
Connected to a large number of devices (printers, workstations etc
what is a microprocessor?
A single chip found in any devices (computers, fridges, alarm systems etc). They process data and instructions to make the device work
why are microprocessors embedded in products?
Personal computers – microprocessors do the calculations to make programs work on your computer.
Digital cameras – microprocessors control the flash, zoom and take the pictures etc
Home entertainment systems – control the display on machine, control output (music, video etc). takes signals from remote control
what are the different category types of personal computers?
+pros and cons?
Desktops – Desktops have more space for components than laptops and provide user with option to upgrade and add components. Needs a peripheral device such as keyboard, mouse , screen, speakers to work. Can hold a lot of data. Is not mobile. Has to be plugged in
Laptops – has keyboard, screen, trackpad and speakers built in. Can recharge battery. Mobile and portable. Typically has less storage and processing capability. Smaller screen and keyboard.
Single-board computers – a single chip that is embedded in another device. Designed to control specific functions for devices - Not flexible. Much simpler than desktop. Might use in cameras, dishwasher, tv etc.
what are the different category types of mobile phones?
smartphones
specialist phones
properties of smartphones
o multi functional device that contains a variety of different sensors.
o Computer chips – functions (apps etc).
o GPS chip – location.
o Gyroscope – angle, tilt and orientation.
o Phone calls too
properties of specialist phones
For specific target market eg partially sighted
Used for people who work in a challenging environment, waterproof, can withstand higher heats etc.
how do mobile phones connect to a network?
Mobile phones use a SIM card to connect to a mobile phone network.
The network uses the SIM card to identify the device.
Mobile phones send radio signals to the nearest mobile phone mast. (SIM is to mobile phone like IP and MAC address is to computer).
Can also use Wi-Fi to connect to a LAN network
what is a tablet device and how is it used?
Tablet screens are bigger than mobile phone screens.
Has a touch screen, apps and WIFI connectivity to provide access to the internet.
Some tablet devices have a sim card slot to allow internet connectivity when not in range of a Wi-Fi signal.
what are the purposes of cameras and camcorders?
Records digital images or videos that can be stored and transferred to a computer.
Uses light sensors to capture images through the lens.
Allows zoom, picture or video capture, download to a computer (USB) view on TV (HDMI), SD card storage, Many have an LCD screen for viewing.
what is the purpose of a games console?
A computer that allows for games to be played on a TV.
Games are on a disc or are downloaded from the internet.
Peripheral controllers attached by wire or wireless. Some use motion sensors.
purpose and use of home entertainment systems
Combination of devices used for home entertainment
Tv – pixels moving on screen
sound systems (sonos) – can produce sound through speakers and amplifiers
Video recorder – records programmes to watch later
Bluray and DVD players – watch films
purpose and use of media players
To play audio and video
Content can be downloaded or streamed (content is played as it downloads)
Can get content from network or directly from the internet.
Can also connect to other devices like TV.
what does gps stand for?
global positioning system
explain the use of navigation aids
Sat-nav use GPS to plan routes and give directions
Other functions include : checking your speed, live traffic reports, rerouting when there is traffic, warning about speed cameras and finding petrol stations.
multifunctional
a device that performs a variety of functions that could be carried out by separate devices. Eg: a smartphone could have a camera, internet and GPS for Sat-nav and can stream music.
convergence
Designs of devices change so that they become like one another. While smartphones and other devices used to be different, nowadays they all have very similar designs. Some laptops now have touchscreens, allowing the to act like a tablet. Some tablets come with attachable keyboards so they can act as a laptop.
explain the term portability
Easy to carry and move around, small in size and weight eg: mobile phone or laptop
explain the term performance
High performance devices perform tasks quickly. The faster the CPU, the better the performance of the task. E.g.: dual core(do 2 things at once) processors in desktops or laptops.
explain the term storage
Files and programmes are stored in storage so the bigger the storage the more files and programs that can be stored. E.g., hard drive on a computer, or USB stick, SD cards
explain the term user interface
+explain all the types
users give commands to a device through the User Interface. E.g.,
Graphical user interface – controlled by pointer (mouse) on the screen controlled by pointer (mouse) on the screen and uses a screen made up of icons and menus.
Command line interface – users enter text instructions, and the computer system provides results or feedback as text. Commands must be typed precisely, since the interface only accepts certain commands.
Menu driven interface – displays a list of options as a menu. A list of options that are not flexible (only these options and no others)
Voice interface – allows user to give spoken commands. E.g. controlling a smart speaker (ok google, Alexa, Siri etc)
Gesture interface – allows the user to control the device by swiping their finger or fingers across the screen, or by pinching to zoom in or out.
explain the term connectivity
Devices can share data by connecting to each other by using wired or wireless connectivity. Examples are wifi, Bluetooth, 4g
explain the term media support
If a device doesn’t have built in media (a screen) you can attach/ connect an adaptor to provide connectivity to an external device. For example your laptop might not have a built in in CD drive, so you can connect an external drive to allow you to play CDs.
explain the term energy consumption
Digital devices require energy to work. Low energy = longer battery life.
explain the term expansion capability
Allows users to install additional components. Example is a mobile phone which might have a slot to install a memory card to have more storage
explain the term security features
Prevents unauthorised access to data. Like a passcode/pin number to access your data.
purpose of systems software
A set of programs that act together to allow the hardware and the application programs to work.
Example; windows operating system, android on a mobile and also hardware drivers like printer software.
When you install a mouse it installs systems software that works in the background
purpose of applications software
A software program that allows you to perform a range of useful tasks (work or excel)
operating systems
A piece of systems software that manages the general operation of the computer__. It is needed to run application software.__ You might use it for file management, security, networking.
systems software tools such as utilities
Utility is a piece of software that performs a useful task. So, antivirus, firewall, VPN, backup.
single user and network features in an operating systems
Single user op- allows for a general user without customisation for different users. So, ring doorbell (one login and everyone accesses same account)
Network op- separates user accounts (multiple logins) to ensure that users cannot access each other’s files but provides access to shared storage and shared resources like printers
memory management features in an operating systems
Allocates the required amount of memory (RAM) to one more application
resource management features in an operating systems
The system resources are made available to applications. Printer, graphics card or processor.
security features in an operating systems
Stops other people from gaining access to your device.
Uses things like firewalls to stop unauthorised users from getting into the system.
Passwords to access applications.
print spooling features in an operating systems
If you print a large item, the computer has the pages ready for the printer faster than it can physically print, so it stacks them up in a ‘queue’
office-productivity software applications
Word, excel etc
Enables you to do complex work tasks such as word processing and spreadsheets
PowerPoint = presentations
Web browsers = access internet
Databases = contain records
web authoring software applications
Website design – allows the user to create web pages and the code associated with web pages
image and sound editing software applications
Allows you to edit and create visual and audio files.
presentation software applications
PowerPoint = produce slide shows and presentations
control software applications
To make something happen in the physical world, alarm system, air con, heating
project management software applications
Helps you to plan and track larger work projects. Can create various tasks with completion dates assigned to different people.
Could have a timeline.
Can track the order of tasks.
free software licensing
Free doesn’t mean free in price, it means the freedom to modify the source code and redistribute it.
Can be more flexible to customise the software but it may not be compatible with other software and you need to be an expert to be able to modify the code.
Gives users the right to study, modify, copy or distribute the program.
open-source software licensing
Volunteers make the source code available to everybody. Open office does word processing and spreadsheets like Microsoft. Sometimes have bugs in them and are not universally used.
Free of copyright and therefore available to anyone.
Costs nothing
Can modify the source code
With many authors it can mean that they share the development and refine it over time. But the downside is that no one owns it, so if anything goes wrong, it is not any one person’s fault.
proprietary software licensing
Owned by the company that develops it (eg Microsoft office).
You have to pay to buy a licence to use it but there are normally limitations: if you buy a licence you cant put it on a friend’s computers because you paid for it on your own device not their’s. If you stop paying, you stop being able to use it.
If there are problems, they will issue a ‘patch’ to fix the bugs.
purpose of communications software
Zoom, video conferencing, text (WhatsApp). More flexible communication for different needs remotely.
Provides a remote access to systems and allows users to contact people using the internet. Can be used to send files, messages, images , audio , video
remote access to systems
Allows either users to access devices or programs from another location.
Means you can be more efficient such as working from home.
Also means that the network manager can control other features centrally such as access restrictions and other security features such as firewall and anti-virus.
different file formats that can be exchanged between difference computers and users
If everyone uses the same or similar file formats, they can exchange data between users and computers. For example, PDF, JPEG, GIF, NP3 (music), CSV, txt
why and how is software updated?
Why – extra features are added fixes bugs and vulnerabilities, more security, improving performance in general, increase compatibility with new operating systems.
How – small patches are delivered via internet or through physical means like a disc or USB.
possible risks to data/systems when software is updated
A malicious organisation could insert code that does something that wasn’t intended, like shares data. It could break the software. Sometimes there is a conflict between other programs on the software.
monitors as an output peripheral device and when they would be used
Monitors show what has happened on the computer. Visual electronic display
explain a monitor’s screen size
Screen size is measured diagonally so the bigger the screen size, the larger the output
explain about a monitors resolution
Measured in pixels, generally, the more pixels, the better the image. If you don’t have enough pixels and it looks pixelated.
printers as an output peripheral device and when they would be used
Printer prints a physical copy of a document or image
features of a laser printer
Has a rotating cylinder that holds an electric charge. This places the toner onto the paper via heat.
features of a inkjet printer
Use cartridges with different coloured ink (usually a black, cyan, magenta and yellow) and the printer sprays tiny dots onto the paper to produce images or text.
compare inkjet and laser priners
speed
cost
cost per copy
colour printing
quality
where used
inkjet
fast
medium
high
yes
high
home printing and photographs
laser
faster
expensive
medium
yes
higher
high volume printing (offices)
features of a laser 3D printer
Creates real life versions of digital models. It adds layers of heated material from the bottom to the top. Creates very complex shapes. Used to make prototypes or scale models.
plotters as an output peripheral device and when they would be used
Used by professionals such as architects and cartographers. Draws high quality images by drawing lines using a pen. It creates very high quality but slow and expensive.
data projectors as an output peripheral device and when they would be used
Used for home entertainment (tv and games) or presentations in business meetings. Project onto a wall or a screen. Uses a bulb to project the image. Resolution can differ depending on quality, and some can zoom in.
speakers as an output peripheral device and when they would be used
Allows the user to hear sound converts electrical signals into sound waves. Often come in pairs for stereo sound. Or multiple speakers for surround sound in entertainment speakers.
control devices as an output peripheral device and when they would be used
Known as actuators.
Make something happen in the real world.
Examples : heaters, lightbulbs, buzzers, pumps
keyboards as an input peripheral device and when they would be used
Allows text numbers and symbols to be entered into a computer
mouse as an input peripheral device and when they would be used
Used to move an onscreen pointer. Commonly used with graphical used interfaces
tracker balls as an input peripheral device and when they would be used
A pointing device with is a large ball that the user spins to indicate direction
joysticks as an input peripheral device and when they would be used
Used to play games, forward back left right
graphics tablets as an input peripheral device and when they would be used
A tablet that simulates paper to draw designs
scanners as an input peripheral device and when they would be used
Scans printed photos or text, and saves hem as electronic versions or documents
digital cameras as an input peripheral device and when they would be used
Captures digital photographs
webcams as an input peripheral device and when they would be used
A basic video camera used for a live video feed into the computer.
microphones as an input peripheral device and when they would be used
Converts sound into signal which is fed into the computer
touch screens as an input peripheral device and when they would be used
An alternative to a pointing device. The user selects items by touching the surface
OMR readers as an input peripheral device and when they would be used
(optical mark recognition) allows the computer to read multiple choice forms.
OCR readers as an input peripheral device and when they would be used
(optical character recognition) converts images of texts into a text file such as a word processing document.
bar code scanners as an input peripheral device and when they would be used
A numeric code represented as a series of lines read by a scanner
biometric scanners as an input peripheral device and when they would be used
Used to measure the features of a person to recognise them (eg fingerprint)
magnetic stripe readers as an input peripheral device and when they would be used
Holds data on a card and is swiped through a machine to send data to the reader
chip and pin devices as an input peripheral device and when they would be used
Modern credit cards use a chip of computer memory to store data which is read back by the reader. More secure than magnetic stripe.
sensors as an input peripheral device and when they would be used
Detects certain things (temperature, motion, water)
the difference between storage devices and the storage media used to store data
A storage device links to the storage media and access to the data on the media.
For example, a CD disk is the media which stores data, the CD drive reads the data on the disk.
Storage device = reader (CD player)
Storage media = contains data (CD disk)
what does HDD stand for
hard disk drive
characteristics of hard disk drives
the hard disk drive is the thing that reads the media
Hard disk drives contain hard disk media (the disks that hold the data).
what does SSD stand for
solid state drive
characteristics of solid state drive
It’s a storage device that reads flash memory media. No moving parts
Same as hard disk drive but reads flash memory instead of hard disk media
Based on electronic circuits
Uses flash memory – a type of electronically erasable programable memory (you can remove what’s on it and put new stuff)
Drawbacks are: more expense form of storage, more limited lifespan
characteristics of optical disk drives
Things like CDs, DVDs and Blu-ray
Read using a laser.
internal and external storage devices
External – can be detached, secondary storage ,
Internal – inside the device(hard disk that plugs in,)
(different to internal hard disk)
DVD/CD player also
hard disk storage media
Made of platters which make a cylinder that spins on a central spindle. A read/write head moves on an arm across the platter. The amount of time that it takes depends on how fast the cylinder rotates. Normally 5400 rpm.
Holds a lot of data and is fast access (transfers files very quickly)
Stores everything on computer
Like the computer had cds in it
media and secondary storage
MEDIA
in a desktop or laptop computer there is usually a hard disk
Hard disk is a concentric disk made of platters
Spins on a spindle
A head moves across tracks on the platter to store data.
Optical media – things like CDs, DVDs, Blu-ray
Flash media – used in portable devices. More energy efficient since it doesn’t have moving parts. (SD card)
SECONDARY STORAGE
Devices that connect to a computer externally.
You could have a hard disk drive, solid state drive, optical disk drive
Attached to the device, rather than being stored internally
Can be taken away.
Could be a hard disk
Note 
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