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1.7 Lesson 1Systems software: A type of software that controls the computers hardware. It provides an interface between the user of the computer and the hardware. An OS is a type of Systems SoftwareOperating Systems: Provide an interface between the user and the hardware. They are said to provide a Virtual Machine that hides the complexities of the hardware from the user. The user doesn’t need to understand where on the disk a file is being saved to, just that they have clicked save and the Operating System deals with the rest.Process Management: The activity that has just been completed is similar to how the processor has to divide its time between processes. It may allocate a small “time slice” to each separate process so that it appears that many processes are taking place at the same time (multitasking). Memory Management: The OS allocates memory between the different programs that are open at the same time. Programmers and users do not need to know where in memory data is being held – it is the purpose of the Operating System to do this.Peripheral Management: Operating Systems manage the way in which hardware interacts with software. A peripheral is a piece of hardware that is not directly connected to the CPU – such as a keyboard, a mouse or even a hard disk drive. An Operating System managed all of the peripheral devices that are connected to the computer – this allows them to be disabled, or drivers be updated. In windows you can access Windows Device Management.User Interface: Command Line Interface- Text based - E.g. DOS, Raspbian (for Raspberry Pi)Graphical User Interface- Contains Windows, Icons, Menus, Pointers- Visual - E.g. Windows 10, Windows 8, Android, Mac OSDrivers: A piece of software used to control a piece of hardware. Drivers allow a peripheral device to be connected to a computer and it be used by an Operating System. You may get drivers for graphics cards, mouse, sound card, network interface cards. Drivers are OS specific and are regularly updated by companiesFile Management: Like memory management, the Operating System must identify where files are stored for long term storage on for e.g. the hard disk drive or a solid state drive. The user does not need to know the specific track, sector and surface address – but the Operating System does in order to accurately locate a file on the hard disk drive.Multi-Tasking:If the tasks were split like this, we would have to wait until all Task A is complete, before completing Task B. This means that we will not have issues when sharing resources, but could make some tasks appear to take a very long time to execute.By giving the processor a small time slice for each task means that all tasks appear to be executing at the same time. To the user it appears that we can multitask and have lots of programs open at once. In reality resources such as memory and the processor are being shared amongst tasks.Utility Software: Utility programs are designed to do just one or two tasks Utility software interacts with the computers hardware E.g. the Disk Drive, Utility programs are inbuilt in to the Operating SystemUtility Programs: File CompressionDisk DefragmentationFile RepairDisk CopyingDisk FormattingDisk Backup / RestoreAnti-VirusCompression: Reducing the size of the file by performing an algorithm on the original dataLossless - The original file can be re-created as no data is lostLossy - Some of the original data is lost and the original file can not be re-createdDefragmentation Software: When a hard disk drive is new – files get added onto the disk in order – very much like starting with a blank piece of paper and adding to itAs files are deleted – this leaves gapsWhen new files are saved – the files fill the gaps and become fragmentedDefragmentation software groups fragmented files back togetherEncryption Software: Encryption means to scramble data in a way that it is unreadable to anybody who doesn’t have a key to be able to unscramble this. Data is encrypted using a key and then decrypted using a key. Data is encrypted so that it is unreadable if anyone is to intercept it.Backups: Completed to ensure there is a way of restoring files/data/programs in case of computer failure .Copies of data and/or software are taken regularly and usually stored in a different location Ensures that if computers are stolen or damaged in for e.g. a fire or a natural disaster that data can be restored and a company do not lose much money.Full: A copy of all data and software on the hard disk drive / server is copied to a backup medium (e.g. an external hard disk drive / DVD-R) and the medium is kept at a different location Take a long time to complete (usually overnight) Recovery takes a long time as it restores all data and programsIncremental: A full backup is made initially. Each night only the files which have been changed since the last incremental back-up are copied Much faster to complete that full back-ups Takes much longer at restoring than a Full Back up as the full back up would need restoring first and then every incremental back-up since the last full back up ................
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