ICT systems In every Day Flashcards
Hard disks
- Main storage device of a computer system
- a read/write head for each surface
- Access speeds are faster then a CD drive
Optical disks
- Data is burned onto the surface
- The disks are supplied with information e.g music
- The user can read data but not write to it
- The cost is determined by the application stored on it
Magnetic tape streamers
-A tape streamer reads and writes data stored on magnetic tape
(DAT) digital audio tape
-Transfer of data is slow because magnetic tape uses serial access
-Magnetic tape is an inexpensive way to store large amounts of fat
USB flash drives
- Flash drives are referred to as ‘pen drives’
- The flash drive becomes active when plugged into a USB port
- They are portable devices that use low power consumption
- They work on the principle of ‘plug and play’
- Cost is linked to capacity of the USB flash drive
ROM (read-only memory)
- This type of memory can be read from but not written to
- Programmes stored on ROM are permeant therefore ROM is non-volatile
- This type of memory stores the ‘booting up’ Programmes for the windows operating system
RAM (random-access memory)
- This type of memory can be read from but not written to
- It is volatile which means the contents of memory are list when the computer is switched off
- It is used to hold the current application Programmes and data that the user is working with
Cache memory
- Similar to RAM in that instructions can be read from or written to
- It’s purpose is to store frequently accessed programs instructions
advantages of LAN
- Expensive peripherals can be shared between a number of computers
- Users can communicate with each other on the network e.g electronic conferencing
- Users have flexible access
File server
- More powerful than other computers, with a large amount of RAM and hard disk space
- It manages file and network security across the network
- It makes sure that only authorized users log on to the system
Network Interface Card
-Each computer must have a network interface card so that it can communicate with devices on the network
-A network cable inserted into the port on the NIC connects the PC to the file server
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Switches
- Connects to a group of computers
- Connects to a file server
- Can send data to a particular computer
Router
- Shares a network connection between devices
- May have integrated security features e,g firewall
- Translates information from the internet so that the computers on a LAN can understand it
Encryption
- Data can be encrypted to prevent unauthorized access
- Data is encrypted or encoded using encryption key software
- Encrypted data is unreadable to anyone who intercepts it
- Only a user with the encryption key can read the software
Define virus
A computer program designed to damage some aspect of an information system
Define worms
Worms are virus’s which spread by replication and do not have to be attached to a document or programme
Define Trojan horse
Gain entry to a users computer ‘in disguise’, the user may think the programme is helpful
Mobile phones
- Use radio frequency to transmit data
- Are small, portable and easy to carry around
- Can be used anywhere there is a network coverage
Expand PDA
Persona, digital assistants
Laptops
- are wireless-enabled
- can be connected to a wireless network using WI-FI technology
- Use Bluetooth technology to pair with devices e.g printers
Expand Wi-Fi
Wireless fidelity
Expand 3G
Third generation
Expand WAP
Wireless application protocol
Advantages of wifi
- Users can log on in any location
- Users can use a wide range of devices
- A network can be setup without wires
Disadvantages for Wi-Fi
- Signal strength varies according to distance from the wireless router
- The connection may not be as secure as a wired connection
- Weather conditions may affect the connection
Advantages of 3G
- Coverage is available where normal broadband is not
- Devices can also be used for voice calls and a range of other data services
- Video calling is possible
Disadvantages of 3G
- Performance is affected by network coverage and the string of the signal
- Increased power consumption requires a larger, high-capacity battery
- Data transfer can be expensive
Bluetooth advantages
- Signal can penetrate solid objects
- Line of sight is not needed
- The cost is lower and les shower is used then with other technologies
Disadvantages of Bluetooth
- Signal carries over only a short range
- Security is at a lower level
- Data transmission rate is lower
Advantages of WAP
- Coverage is available where normal broadband is not
- Network services and information can be accessed from a mobile device
Disadvantages of WAP
- Data transfer is slow
- Availability is limited
- WAP is less popular now smartphones provide full browser
Define internet
A network of networks that don’t contain information and provide transport links for information to pass between computers
Define World Wide Web
- Is an application that runs on the internet
- Is the largest and most used service on the internet
- Can be described as a multimedia service on the internet
Define intranet
An intranet is a private network website used within an organisation
