Please enable JavaScript.

Coggle requires JavaScript to display documents.

IT paper one - Coggle Diagram

- - - - source code is the software code written by programmers - if a software is open source it means users can view and modify the code.
      - linux, python and firefly are open source
      - advantages
        
        because the source code can be edited, it can be customised to an organisations needs
        
        unwanted features can be removed to make the software run faster
        
        users can work together to modify, debug and improve a project
        
        open source is often low in price and can sometimes be free
      - disadvantages
        
        there are security risks - some editors may add malicious code to the program
        
        the code may be prone to errors and may not have been tested properly
        
        it may be difficult to receive support as development is often distributed between people in different locations
    - - users can only view or modify the software - they will have the right to use the software but they dont actually own it - microsoft office, fortnite, and spotify are all examples of closed source software
      - also known as proprietary software.
      - advantages
        
        code is well tested and has been professionally developed - updates will be secure
        
        the company can be held accountable if it does not perform as listed in the terms and conditions upon purchase
        
        most developers will provide help
      - disadvantages
        
        users must rely on the company to fix issues and provide updates - may be infrequent or stop completely
        
        not free
        
        users are unable to modify, debug or imrpove the code for their own benefit
  - - - General use software for completing tasks accurately and efficiently, key examples are word processors, presentation software and web browsers
      - Email applications are beneficial to organisations because staff can send information to multiple customers at once - making it simple and more cost effective.
      - Databases and spreadsheets
        
        Both of these options can store both numerical and textual data ready for analysis. Examples include tables and financial spreadsheets of a company's profits for that year.
    - - tools for programmers who are creating or modifying software
      - an integrated development environment is used to create and edit programs, these feature translators ( a program that converts one type of language to another), compilers ( a translator that converts instructions into machine code) and a debugger (used to test code and display errors)
    - - Specialist software for businesses, often made bespoke for an organisation
      - an example of business software is design packages such as CAD (computer aided design) - used to design and manafacture products
      - Project management software - allows teams of workers to collab and divide projects into manageable tasks
  - - - A copy of data that can be used if the original data is corrupted or lost, backups of all data should be made regularly and stored in an alternative location
      - Imaging (disk cloning) creates an identical image of a storage drive to be stored in a different location.
- - - - Keyboard - sends data about what keys have been pressed into the computer
      - Mouse - sends signal data into the computer system when the user moves it or clicks a button
      - Microphone: takes voice data and digitises it,sending it into the computer system for processing and storage/.
      - Web cam - takes visual data and sends it into the computer system for use in a wide range of applications
    - - Monitor - Takes data from the computer system and displays it in a visual format
      - Speakers / headphones - takes digital sound data to output to the user via speakers
      - Printer - Outputs a digital file on paper so users can keep records of important files without need of access to a computer.
    - - Sends signals to other computer systems - sends packets of data across a network and can either be wireless or connected by ethernet
        
        Has a globally unique address - MAC address.
    - - A Modem takes digital signals from a computer system and turns them into analogue data in order to send it across a network, once it is received, another modem will convert these signals back into a digital format.
      - A router connects networks across the internet, it manages data packets by determining the shortest path to their destination network. It uses algorithms to determine the quickest route to take.
        
        Home routers connect to their ISP who manage the transmission of packets - larger organizations manage their own packet transmissions
        
        Routers are essential to connect a LAN to a WAN.
        
        Looks up the IP address of a packet and sends it to a destination.
    - - A small box that allows nodes on a network to be connected - transmits data packets, however isinsecure compared to a switch as when a packet arrives at the hub it is forwarded to all nodes connected, causing data collisions.
    - - Allows a larger amount of computers to be linked so that they can share data - more secure than a hub as it results in less collisions and packets are only sent to the destination node. However they are more expensive than a hub.
    - - Creates a link between both wired and wireless networks - creating a wireless local area network that allows wifi enabled devices to connect to a wired network.
    - - scenarios
        
        problem - one of the cam pc's is unexpectedly rebooting
        
        steps:
        
        event / system log: identifies and diagnoses software and hardware issues
        
        POST: provides a series of beeps to identify faults in the system
        
        steps: check event log for any error messages
        
        run post card to identify hardware faults through beep codes
        
        address identified issues accordingly
        
        problem: office pc not starting
        
        steps + techniques
        
        physical checks - check if power supply and cable connections are valid
        
        beep codes: listen for beep codes during startup
        
        steps: Check power cable is plugged in and functional, listen for beep codes and refer to the manual for troubleshooting, if no beep codes consider replacing power supply unit
        
        network printer not printing
        
        ping test -checks network connection
        
        event logs - check for system errors / warnings
        
        perform ping test to verify network connectivity - check event log for any system or network related errors, refer to manual of printer.
  - - - Known as a CPU (central processing unit) - considered the 'brain' of the computer system
      - all instructions are carried out in the CPU, coming in a range of speeds but commonly run at over 3Ghz (3 billion instructions per second)
      - Contain multiple 'cores' - which are treated as if they are separate CPU's themselves, modern cpus have between 2 and 32 cores
      - processes data and instructions
    - - the main circuit board of a computer - components such as the CPU and ROM are connected here
    - - Magnetic Storage - a magnetic hard disk drive is the most common form of secondary storage in desktop computers
        
        A read/write head moves above the disk and uses the magnetic field to red or edit data - hard drive disks can also be external and connected though a USB port.
        
        The floppy disk was a type of magnetic storage, however this has been replaced by solid state devices - which are faster and have a much higher capacity.
        
        Magnetic tape - has a high storage capacity but data has to be accessed chronologically so it is only used by companies to back up / archive large amounts of data.
        
        Characteristics: Large capacity and cheaper per gigabyte than a solid state drive
        Not durable, not very portable when powered on - moving it can damage the device.
        Relatively quick access speed, but slower than solid state drive.
      - Optical Storage - uses a laser to project beams of light onto a spinning disc, allowing it to read data from a CD, DVD or a Blu-Ray disk.
        
        The slowest form of storage
        
        Typically Internal, however external disc drives can be bought for laptops.
        
        Characteristics: Low capacity; 700 MB for CD's, 4.7 GB for DVD's and 25 GB for Blu-Ray discs.
        Not Durable because discs can scratch or break easily
        Discs are thin and portable
        Slower access speeds.
      - Solid state storage - No moving parts in solid state storage, usually quieter, faster and use less power than magnetic HDD's
        
        USB drives are a type of SSD;s - used to transport files easily because of its small size.
        
        Memory cards are also another example of SSD
        
        Characteristics: High capacity, more expensive per gig/ than magnetic
        usually durable but cheap USB sticks can snap or break
        Small size means they are very portable
    - - SCSI ( small computer system interface) is a protocol for attaching external devices to a computer system, like a printer, storage drive or a scanner.
      - SAS (serial attached SCSI) is an improves version of SCSI - allows for many more external devices (up to 128) to be attached at the same time to a computer system.
    - - Dedicated circuit boards - they have a specific purpose and are attached to the motherboard
        
        Graphics cards - Process graphical data and converts it into a displayable output on a monitor.
        
        Network Interface card
        
        Fibre Channel Card - transfers data between servers across a network - they usually allow for quick transfer speeds and is primarily used to connect data storage to servers in large data centres
        
        Sound card - converts analogue sound waves into binary when audio is input through a microphone - they also convert binary back into analogue to output audio through speakers or headphones
      - Many of these cards can exist as integrated components as opposed to a separate card.
    - - USB Port - Connects storage devices such as usb sticks or external harddrives - can also be used to connect input devices such as keyboards and mice.
      - Firewire port - similar to USB however developed for Apple Products - transfers data at a high speed.
      - Ethernet Port - connects computers to Network Devices such as a modem or router, allowing access to the internet.
      - SATA port - Allows data transfer to external HDD, SDD or optical drives.
  - - - slow running application on computer
        
        steps:
        
        baselines- compares the current performance against a standard
        
        event logs: logs errors and issues
        
        check the baseline to see whether or not there is a drop in performance, then check event logs for any software issues or warnings - address identified issues accordingly
      - missing files from directory
        
        file history - use file history to recover previous versions of files
        
        anti virus scan - checks for malware activity
        
        use file history to recover previous file versions, and then run an anti virus scan to check for malware. Update the anti virus database and take protective measures
      - frequent browser crashes
        
        use browser logs to identify errors and issues
        
        boot browser in safemode to troubleshoot without any third party extensions.
  - - - copper cables
        
        has been used longer than fibre optics, considerably cheaper that is usually poorly insulated and therefore susceptible to electromagnetic interference
        
        more likely to suffer from attenuation (network distortion)
        
        however they are more malleable and less likely to break - although they do have a lower bandwidth so they can not transmit as much data as a fibre optic cable
      - fibre optic cables
        
        very fast but expensive. signals are transmitted as waves of light through a glass tube, because of this fibre optic cables arent affected by electromagnetic interference and suffer less from attenuation
        
        have a higher bandwidth and can transfer more data at one time
    - - bluetooth
        
        a temporary short range communication between devices within a limit of around 10 metres
        
        bluetooth can be used to transfer audio files from one smartphone to another
        
        the close proximity is a disadvantage by no other hardware is required for a connection
      - infrared
        
        have been replaced by bluetooth or wifi connections as infrared requires devices to be in direct line of sight - however it is still used by some devices such as remote controls, only works a short distance
      - microwave
        
        use radio waves to send signals across a large area via microwave towers - it can transmit a large amount of data but antennas bust be in the line of sight of eachother with no obstructions.
        
        microwave connections are affected by bad weather, leading to higher chances of attenuation.
      - laser
        
        an uncommon form of connection, laser connections can send data to devices that are in line of sight of eachother as long as there are no barriers present
        
        laser connections can transmit data up to 2km but bad weather severely affects the transmission rate.
        
        laser connections can be used in space as there are fewer barriers between the satellites
      - satellite
        
        satellite networks use point to multipoint communication by using satellites above earths atmosphere that recieve a transmission and rebroadcast them back to earth. because of the distance between the communication device and the satellite, there is a delay between data transmission and data being recieved.
      - 5g
        
        allows mobile phones to connect to a network for calls and text messages.
- - - - for a device to be able to communicate on a local network, it needs an IP address to be identifiable.
  - - - Clients will make requests to the server, the server manages that request and responds, for example, if a user requests to access www.bbc.co.uk to a web server
      - Larger services need very powerful servers to handle millions of requests a second
      - The client is completely dependent on the server to provide and manage information
      - The server controls network security, backups, and can be upgraded to manage higher demand.
      - Advantages
        
        network can be controlled centrally from the server
        
        hardware, software and resources can be shared across the network, such as printers, applications and data files
        
        network allows for improved scalability - more clients can be easily added
      - Disadvantages
        
        large amounts of traffic will cause the network to slow down
        
        if a fault occurs within the server then the whole network will fail
        
        it technicians may be needed to manage and maintain the network
        
        malware can spread quickly
    - - data is shared between systems without requiring a central server
      - each computer is responsible for providing data
      - optimal for sharing files that can be downloaded
      - advantages
        
        simpler network than client server - can be set up more easily as servers arent required
        
        clients arent depending on a server
        
        perfect for quickly sharing files between systems, such as downloading media files
      - disadvantages
        
        without a dedicated server there is no central device to manage security backups
        backups must be performed on each individual system
        
        computer performance will decrease with more devices connected to the network
    - - bus topology
      - mesh topology
      - star topology
      - ring topology
  - - - Allows one physical server to host multiple virtual machines that run seperately
    - - a full desktop environment where processing happens remotely, where an operating system is managed and hosted centrally but displayed locally on a different computer
      - a problem with virtual clients is that the users will be unable to work if network connectivity is lost- an increased load on the server may result in poor performance for each client.
      - a common use for virtualisation is in application testings before they are used on the main system
    - - Combines multiple storage devices so that they appear to be just one device
    - - accessed through a network, primarily the internet. A cloud server is an advantage of storage virtualisation as data can be stored across multiple devices.
      - Private cloud
        
        Where businesses have their own data centre that can be accessed by employees, allowing for flexible and convenient data storage and gives the business control over data management and security
      - Public cloud
        
        Uses third party storage providers such as google drive or dropbox to provide storage over the internet. Typically a pay for use service - businesses pay for amounts they need.