System Softwares

Mind Map by TS P, updated more than 1 year ago
Created by TS P about 6 years ago


Advanced Level (A- Level) Computer Science (System software) Mind Map on System Softwares, created by TS P on 11/02/2015.

Resource summary

System Softwares
  1. Operating systems
    1. Duties
      1. Managing the use of hardware (inputs and outputs) across many programs
        1. Provides an environment for programs to be executed
          1. Provides communication between user and the machines
            1. Overlooks computer's operations
            2. Provides
              1. File management
                1. stores files in hierarchical structure,storing a record of their directories
                2. Memory management
                  1. Memory management: Makes the most efficient use of RAM. Each task is given a proportion of the memory and so this allows many tasks to be able to run at the same time
                  2. Input/Output management
                    1. Queues the requests for the use of the I/O and executes them in that order
                    2. Processor management
                      1. OS manages which task gets the next use of the processor
                      2. Data security
                        1. Network and multi user OS can provide each user with an account followed by a password, and accessibilty hierarchies
                      3. Types of OS
                        1. Batch processor
                          1. Do repetitive tasks for different data sets. Once initiated with an input, the Batch OSs is left to procedeed until all iterations are completed. Typically found in mainframes and typically used for processing paychecks
                          2. Real Time
                            1. Takes in inputs and produces and inputs at different rates.Immediate updating of files and immediate response to the user. Examples: car engines, traffic lights
                            2. Single User-Single applications
                              1. Single User - Multiple applications
                                1. Multiple users - multiple applications
                                  1. Network OS
                                    1. OS that can allow computers to be connected into a network.
                                      1. Maintain connection
                                        1. logging users on
                                          1. Provide security between users
                                    2. Utility Programs
                                      1. Disk Defragmenter
                                        1. Big files may be divided up into smaller fragments that are stored in a noncontiguous manner, defragmenters relocate these fragments and any unused disk space so they can be stored contiguously for faster accessing speed
                                        2. Disk Formatter
                                          1. Draws lines on hard disks to create storage areas for the disk's initial use
                                          2. Virus checker
                                            1. Constantly find and remove viruses from sent files, downloaded files and copied files
                                            2. Auto backup
                                              1. Files can be periodically backed-up on scheduled basis by creating duplicates of the desired files and folders for servers, clients, mainframes etc. and stored in alternative media in the event of hard drive failure
                                              2. Compressor
                                                1. Reduces file size by removing unwanted parts of a file which ultimately speeds up computer performance
                                                2. Disk content Analyser
                                                  1. Generate a visual representation of the storage space on the disk occupied by folders, files and programs, may create graphs to show this.
                                                  2. System software made to analyse, maintain and configure the computer
                                                    1. Utility programs are not user-oriented
                                                    2. Library Programs
                                                      1. Collection of codes, instructions, data and resources that can be used by various programs
                                                        1. e.g. programs running on Windows 7 all use the same transparent theme that the windows currently have, or the system buttons (close, minimise, maximise...)
                                                        2. Helps the running and development of more complex software
                                                          1. DLL: Dynamic Link Library: loaded dynamically into the OS when a task is needed. It's executable and handle a wide range of tasks like controlling messageboxes, handling graphics ...
                                                            1. Advantages
                                                              1. capable of making advanced programs
                                                                1. Less time consuming
                                                                  1. Testing becomes less necessary
                                                                  2. Disadvantages
                                                                    1. Some tweaking might be needed for personalisation - might be tedious
                                                                      1. Prone to virus attacks from the exposure to various files
                                                                    2. Language Translators
                                                                      1. Assembler: Assembly language codes into binary (object code)
                                                                        1. Compiler
                                                                          1. Translates HLL into object code all at once
                                                                            1. This is to create an executable program
                                                                            2. Translates all the source code at once
                                                                              1. Leaves the user with the source code that is about to be executed
                                                                              2. Advantages
                                                                                1. No plaigiarism from other users
                                                                                  1. Easy distribution of .exe code
                                                                                    1. Once .exe file is produced, the compiler software is no longer needed
                                                                                    2. execution time faster than that of interpreter
                                                                                    3. Disadvantages
                                                                                      1. Slow preparation (translation) time
                                                                                        1. If there is a mistake, program wont run or will crash or run incorrectly therefore the program needs to be error-proof first
                                                                                          1. Uses a lot of resources
                                                                                        2. Interpreter
                                                                                          1. Translates one line of code at a time
                                                                                            1. A translation method of HLL into object code
                                                                                              1. Advantages
                                                                                                1. Can be executed before the entire source code has been translated
                                                                                                  1. Less time consuming to translate
                                                                                                    1. A chance to fix mistakes after the execution of a line (easier to debug)
                                                                                                      1. Great for prototyping
                                                                                                      2. Disadvantages
                                                                                                        1. Execution time slower than compiler
                                                                                                          1. Since source code is exposed - greater risk of plagiarism
                                                                                                            1. A full final executable file is not produced
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