software notes

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  • Created by: loupardoe
  • Created on: 12-06-16 15:19

What is software?

writing software

  • software is written by programmers using programming languages
  • programming languages are themselves software
  • the CPU can only recognise instructions that are given to it as binary bit patterns
  • such instructions are called machine code
  • machine code is a low level language which means it works low down at the hardware level
  • each machine operation has to be written by the programmer
  • writing software in machine code is difficult
  • high level languages allow the programmer to set out algorithms without having to worry about every single action carried out by the CPU
  • it is difficult to produce robust and reliable software
  • writing software is still quite a new activity for humans and there is not a long tradition about how it should be done
  • various methods have been invented in order to lay down rules about how writing software should best be approached
  • this is the discipline of software engineering

types of software

  • system software- software that is written to control and make use of the hardware. acts as an intermediary between the user and the hardware and also between applications and the hardware
  • applications are what computer users by computers for. these are programs whcih do the real-world tasks that the users want
  • applications need to make use of system software in order to make the hardware do what is required

system software

  • consists of operating systems, device drivers, firmware, servers, utilities and interfaces
  • often taken to include development tools such as compilers, interpreters, linkers and debuggers

operating systems

  • the operating system is a large collection of programs that the hardware what to do
  • operating systems are necessary to run all applications, except those which are self booting
  • they are found in nearly all computing devices
  • oversees such operations as transferring data between memory locations, the CPU and the disks; producing visual displays on the screen; controlling peripherals; protecting data from being accidentally overwritten
  • sometimes referred to as a platform
  • this means that it provides an environment where applications can run
  • applications must be written to conform to a particular platform and this imposes a degree of consistency on them
  • applications make use of the kernel to operate the hardware
  • ensure that applications are less likely to cause problems with basic memory operations

user interface software

  • the user interface is the boundary between the human user and the machine
  • lets the user give commands
  • asks questions
  • displays a response
  • operating systems provide different ways of doing these things
  • command line interface- requires the user to type commands; these are translated by a command interpreter into signals that the computer can understand; you can completely control a computer system with commands which is why technicians and programmers like using them
  • they also find it useful to group commands together in shell scripts to carry out maintenance jobs auomatically
  • a shell is software that a user needs to communicate with the kernel

memory management

  • operating systems have to decide what goes where in memory
  • they have to make…

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