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IT LO3 - Coggle Diagram
IT LO3
3.4 - business systems
LAN - local area network, such as in a school.
WAN (ADSL) - used to transfer data across copper telephone wires. Requires a modem at both ends to use. High bandwidth, low security. A firewall or VPN should also be used. High amounts of use, for example at peak times, can increase latency
WAN - leased line - Provides a fixed connection with a high bandwidth. It is not affected by peak usage times.Can be expensive.
PSTN - Connection of wired telephone networks that span the world. Used to transmit data across huge distances.
Cellular - Uses a cell tower or transmitting tower that is connected to PSTN cabled. May be affected by weather conditions.
Satellite communication - uses point to multipoint communication to receive a transmission from earth, and retransmit it to another place. Used in rural areas
Duplex - Data sent both ways at one. Half duplex - data can be sent both ways, but not at the same time. Simplex - data can only be sent in one direction.
3.1 - Types of server
File server - Used to centrally store and backup files in a network, frees up physical space
Print server - used to manage printing requests, including by putting them in a queue, and printing from the first available printer. Increases efficiency
Allows users on a network to access shared applications, such as email or word processing applications. Certain applications may be restricted to certain users.
Database server - used to manage and manipulate database software that can be accessed by users on a network.
Mail server - Used to send, receive and archie emails on a network. USes email protocols, such as POP or SMTP to ensure that emails are delivered to the correct user on the network. Stores company address book, making it easier to contact people within a business.
Hypervisor - Allows a host machine to operate virtual machines, such as guest systems.Virtual machines can share the resources of the host, and it optimizes the host server, by allowing virtual machines to run at their highest possible efficiency.
3.2 - virtualisation
Server Virtualisation - when one physical computer is used to run multiple virtual machines. These machines run separately. One physical server can be divided into multiple virtual servers. This can be very complex and expensive, but it allows the business to run multiple servers, which can easily be scaled up or down.
Client virtualisation - this is when a full desktop can be accessed and processed remotely, for example using a tablet. If connectivity is lost, users will be unable to work, and this type of virtualisation is often used when applications are being tested in a secure environment. Although th enumber of operating systems i limited and extra bandwidth is required, this allows a desktop to be accessed from anywhere, and the virtual desktop doesn't require it's own hardware.
Storage virtualisation - this is when multiple storage devices are combined, so that they appear to be a physical device. This allows storage to be managed from a central console, and improves storage management. It also decreases hardware and software costs, but it can make upgrades difficult to do.
Cloud storage - can be private, public or hybrid (a mixture of the two). It allows data to be stored and accessed via a network. Public cloud servers are usually cheap, but a private one can be expensive to set up.
3.5 - business systems
MIS - used to store, collect, analyse and present data.
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