Computer Networks And Operating Systems

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Computer Networks and Operating Systems Hamza Shahid (13137133) ABSTRACT Part 1: Operating Systems Overview Part 2: Virtualisation What is an Operating System? Table of Contents Explain what an Operating System is, in the context of personal computers. 3 What is an Operating System (OS)? 3 Operating Systems 5 Monolithic 5 Micro-Kernel 5 Layered 6 Explain what virtualisation is in the context of operating systems, and the role of a virtual machine monitor (VMM). 7 What is Virtualisation? 7 Operating System Overview “Operating system, n. The low-level software that supports a computer 's basic functions, such as scheduling tasks, controlling…show more content…
If a process took 45 minutes then the user would have to run 2 blocks simultaneously, taking up 1 hour, this means 15 minutes would be wasted, as the process wouldn’t actually take that long. This means that running a number of processes would take too long. This is considered Phase 1 of Operating systems and is called Serial Processing Phase 2 consisted of batch systems, and was called Simple Batch Systems. This was one of the first OSs that removed the user access to the hardware; there was no longer any direct access, meaning there was less human error, and possible reducing the time it took to start the systems up. This OS functioned by allowing a submission of ‘Jobs’ to a Computer Operator, who would collate group jobs into a batch. These batches are then put into a program, allowing the process to take place. This reduced the number of pauses caused between each batch, allowing faster processing times. Multi-Programmed Batch Systems was an upgrade of Simple Batch Systems. This phase allowed automatic sequencing, which removed the gaps between each batch/job, however the processor was very often idle. Using this system also meant that Input and Output devices took their time; waiting around for them to load would waste a lot of time. As this phase also contains Multiprocessing it allows the OS to switch between jobs while an active job is waiting. The final phase of the OS is Time-Sharing. This was again an upgrade to its
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