Also, when using a virtual operating system, you can have virtual device drivers that fool the operating system into thinking that it is direct communicating with a certain piece of hardware, but in actuality it is going through some function calls to the host operating system. Training in Maths and English for post 16 learners, Structure and function of the processor (1.1.1), Input, output and storage devices (1.1.3), The function and purpose of operating systems (1.2.1). A student glossary is an excellent idea; learners can add terms that are unfamiliar to them and define them in their own words. Scheduling in a computer is where processes are given access to system resources, for example processor time which enables multi-tasking. e) Distributed, Embedded, Multi-Tasking, Multi-User and Real Time operating systems. For example, film animation and CGI takes a vast amount of processing time. Interrupts are useful in computers, as rather than continually polling the inputs for changes, as soon as an event (e.g. The orange game is a simple and fun activity to show how deadlock can occur. An activity can also be found at the bottom of this document which deals with different types of scheduling. Operating systems can quite easily be taught as a standalone part of the specification, and would be logical to go onto 1.2.2 Applications generation, which requires the same level of in-depth understanding. Multi-level feedback queues categorise processes into their own queues which have their own priority. The end result of this program is to draw a picture on a simulated computer display. Round robin allocates a fixed time per process and then cycles through them until they are done. For instance, on an aeroplane when the pilot wants something to happen, it should do so straight away. b) Memory Management (paging, segmentation and virtual memory). The 'How virtual memory works' article is an interesting article about virtual memory in more practical terms. This is kept to a manageable level by using a 'render farm'. Each individual node holds a specific software subset of the global aggregate operating system. e) Distributed, embedded, multi-tasking, multi-user and Real Time operating systems. Paging (also called swapping) – is the process of moving data between RAM and virtual memory. What are the memory requirements for different operating systems and games? h) Virtual machines, any instance where software is used to take on the function of a machine including, executing intermediate code or running an operating system within another. This howstuffworks article gives a good overview of BIOS in more practical terms. Operating system is a crucial component of the system software in a computer system. d) Scheduling: Round robin, First come first served, Multi-level feedback queues, shortest job first and shortest remaining time. The following YouTube video covers the basics of operating systems looking into the different managers (Process, File, Device, Memory). It supplies an interface for the user and important utilities for managing the computer. d) Scheduling: round robin, first come first served, multi-level feedback queues, shortest job first and shortest remaining time. The activity starts off by questioning if students use instant messaging programs, and, if so, how many other programs they have open at the same time. The pupil should be the most organised in the group and should be happy telling the others what to do. Primary/secondary memory – RAM is primary memory, whereas hard disks or flash drives are secondary memory. A distributed operating system (DOS), are systems which model where distributed applications are running on multiple computers, linked by communications. Sign in, choose your GCSE subjects and see content that's tailored for you. A distributed operating system co-ordinates all the activity. OCR’s resources are provided to support the teaching of OCR specifications, but in no way constitute an endorsed teaching method that is required by the Board and the decision to use them lies with the individual teacher. c) Interrupts, the role of interrupts and Interrupt Service Routines (ISR), role within the Fetch-Decode-Execute Cycle. h) Virtual machines, any instance where software is used to take on the function of a machine, including executing intermediate code or running an operating system within another. In distributed systems, many computers connected to each other and share their resources with each other. This leads into a discussion of how a computer might achieve that. A distributed operating system is a software over a collection of independent, networked, communicating, and physically separate computational nodes. Conceptual links to other areas of the specification – useful ways to approach this topic to set students up for topics later in the course. This process is slower than using just using primary memory alone since secondary storage is slower and the data has to move around more. Multiple central … Unix is an example of a multi-user OS. a button being pressed) happens, the CPU is interrupted from what it is currently doing and takes a snapshot of all the registers in the CPU at that point in time so that it can return to that state when it has finished dealing with the interrupt. Read about our approach to external linking. We update our resources on a regular basis, so please check the OCR website to ensure you have the most up to date version. Delivery guides are designed to represent a body of knowledge about teaching a particular topic and contain: a) The need for, and function and purpose of operating systems. Students should discuss why they use certain operating systems. However, some tasks can require much more processing power such as complex scientific/bank calculations. Operating system is developed to ease people daily life. One very important thing to remember about RTO systems is that “the right answer too late is wrong”, since calculations for movements of a robot, for example, that arrive too late may no longer be valid if they are late. Operating systems. This pupil must be a good writer and reader, and must be comfortable doing both in front of the group. Other keywords: Fetch-Decode-Execute Cycle, Scheduling, Round robin, First come first served, Multi-level feedback queues, Shortest job first, Distributed OS, Embedded OS, MultiTasking OS, Multi-user OS, RTOS, BIOS, Drivers, Virtual machine. On some computers it is possible to run a choice of operating systems. Gives students an idea of the limitations of single processors and discusses the advantages and disadvantages of distributed computing. See Device drivers 1 and Device drivers 2 for more information. Each student takes on the role of a different part of a simplified computer and they work in groups to run a simple program. Distributed Operating System is one of the important type of operating system. There are a few common operating systems available: The operating system performs several key functions: Our team of exam survivors will get you started and keep you going. if you can find out one extra fact on this topic that we haven't Virtual Memory – The memory manager can trick the operating system into thinking that it has more physical memory than it actually does by making use of secondary storage such as the hard disk or flash drives. For user benefits and needs the operating system may be single user or distributed. Have they ever had to install a driver? There are different types of operating system. For instance, user and system processes may have their own queues. Interrupt – Interrupts what the CPU is currently doing and performs the ISR, then lets the CPU return to what it was doing before. The topic starts by understanding the need for, and function of, operating systems. See BIOS 1 and BIOS 2. © OCR 2015 - This resource may be freely copied and distributed, as long as the OCR logo and this message remain intact and OCR is acknowledged as the originator of this work. Content: A clear outline of the content covered by the delivery guide; Thinking Conceptually: Expert guidance on the key concepts involved, common difficulties students may have, approaches to teaching that can help students understand these concepts and how this topic links conceptually to other areas of the subject; Thinking Contextually: A range of suggested teaching activities using a variety of themes so that different activities can be selected which best suit particular classes, learning styles or teaching approaches. One member of each group should be chosen as the Scheduler. A single/group card matching task to help students learn about the functionality of an Operating system can be found here. There are different types of operating system. Multi-tasking operating systems are those that allow you to have many different tasks happening at once, and so this is our standard modern operating system. Each queue may have its own prioritisation algorithm. already told you, Click on this link: Distributed operating systems, see For example, Dynamic Link Libraries can be stored on the hard disk until called by main memory by a program. For example, film animation and CGI takes a vast amount of processing time. Students could watch this demo of a virtual machine being used and could discuss why someone would want to do this. Activity involving getting the students to act out a simple computer simulation. Common misconceptions or difficulties students may have. Operating System Windows MCA. A distributed OS is a collection of independent networked nodes. They are generally lower power consumption, low cost and use a limited amount of hardware resources, which means that they need to be interfaced with in a bespoke manner compared to commonplace OS. A distributed operating system co-ordinates all the activity. Paging using a paging table is the process where data is moved to and from virtual memory when needed. The process that happens as a result of the interrupt is called the Interrupt Service Routine (ISR). (See the following links: Introduction 1 and Introduction 2.). This is kept to a manageable level by using a 'render farm'. In many cases, the ultimate consumer of the exposed functionality is a client with a user sitting at a keyboard, watching the output. Real time operating systems are supposed to run under predefined deadlines and so can be classed time critical. How do you think the introduction of the Internet and USB (as opposed to parallel and serial ports) has made drivers less annoying (i.e. The user has the same experience on the virtual machine as they do on a dedicated machine. var today = new Date() See Virtual device drivers section for more information. You will then need to divide the class into groups of 6/7. A virtual machine is an operating system that emulates dedicated hardware. This enables the user to choose which operating system that they would like to use. (See resource link. challenge see This unit content will support elements 1.1.1 ‘Structure and function of the processor’ where students are introduced to the structure of a processor and the Fetch Decode Execute Cycle. Projects such as the 'SETI-At-Home' and the 'The Clean Energy Project' make use of this kind of distributed processing. Shortest job first is where the scheduler prioritises smaller jobs first to get them out of the way. BIOS stands for Basic Input Output System, and is firmware that is designed to run when the PC is first switched on. c) Interrupts: the role of interrupts and Interrupt Service Routines (ISR), role within the Fetch-Decode-Execute Cycle. The first is a ubiquitous minimal kernel, or microkernel, that directly controls that node's hardware. One member of each group should be chosen as the Processor. Each node may have its own hardware associated to it, and there will be some sort of system management software that brings all the interconnected systems together that co-ordinate individual and collaborative activities on the different nodes. It saves cost from reducing the need for separate hardware. There are some advantages and disadvantages of distributed operating system that we will discuss.