Week2 (1).pdf

Operating Systems, Virtualization, and Cloud Computing Operating System (OS) ▸ An Operating System (OS) is an interface between a computer user and computer hardware. An operating system is a software which performs all the basic tasks like file management, memory management, process management...

Operating Systems, Virtualization, and Cloud Computing Operating System (OS) ▸ An Operating System (OS) is an interface between a computer user and computer hardware. An operating system is a software which performs all the basic tasks like file management, memory management, process management, handling input and output, and controlling peripheral devices such as disk drives and printers. ▸ An operating system is a program that acts as an interface between the user and the computer hardware and controls the execution of all kinds of programs. 2 Different Types of OS ▸ There are different types of operating systems such as: ▸ Windows ▸ MacOS ▸ Linux ▸ DOS ▸ iOS ▸ Android etc. 3 Windows 4 MacOS 5 Linux 6 DOS 7 iOS 8 Android 9 Following are some of important functions of an operating System: ▸ Memory Management ▸ Processor Management ▸ Device Management ▸ File Management ▸ Security ▸ Control over system performance ▸ Job accounting ▸ Error detecting aids ▸ Coordination between other software and users 10 Memory Management ▸ Memory management refers to management of Primary Memory or Main Memory. ▸ An Operating System does the following activities for memory management − ▹ Keeps tracks of primary memory, i.e., what part of it are in use by whom, what part are not in use. ▹ In multiprogramming, the OS decides which process will get memory when and how much. ▹ Allocates the memory when a process requests it to do so. ▹ De-allocates the memory when a process no longer needs it or has been terminated 11 Processor Management ▸ In multiprogramming environment, the OS decides which process gets the processor when and for how much time. This function is called process scheduling. ▸ An OS does the following activities for processor management : ▹ Keeps tracks of processor and status of process. The program responsible for this task is known as traffic controller. ▹ Allocates the processor (CPU) to a process. ▹ De-allocates processor when a process is no longer required. 12 Device Management ▸ An Operating System manages device communication via their respective drivers. It does the following activities for device management − ▹ Keeps tracks of all devices. Program responsible for this task is known as the I/O controller. ▹ Decides which process gets the device when and for how much time. ▹ Allocates the device in the efficient way. ▹ De-allocates devices. 13 File Management ▸ A file system is normally organized into directories for easy navigation and usage. These directories may contain files and other directions. ▸ An Operating System does the following activities for file management − ▹ Keeps track of information, location, uses, status etc. The collective facilities are often known as file system. ▹ Decides who gets the resources. ▹ Allocates the resources. ▹ De-allocates the resources. 14 ▸ Security − By means of password and similar other techniques, it prevents unauthorized access to programs and data. ▸ Control over system performance − Recording delays between request for a service and response from the system. ▸ Job accounting − Keeping track of time and resources used by various jobs and users. ▸ Error detecting aids − Production of dumps, traces, error messages, and other debugging and error detecting aids. ▸ Coordination between other software's and users − Coordination and assignment of compilers, interpreters, assemblers and other software to the various users of the computer systems. 15 Tasks of the Operating System: ▸ Accepts inputs from the mouse or keyboard. ▸ Sends outputs to the monitor or printer. ▸ Recognizes peripheral devices such as external hard disks, pen drive, web cam etc. and makes sure that software needed for the hardware to run is installed. ▸ Manages files and folders in the system (Naming, Creating, Moving, Finding and Deleting folders etc.) ▸ Allows applications software (word-processing, spreadsheets etc.) to communicate with the system's hardware. 16 ▸ Shares out system memory efficiently. The operating system will decide how much memory to assign to particular tasks. It also moves data in and out of memory. ▸ Loads and runs software applications. ▸ Manages system security. For example - allows passwords to be added / changed. ▸ Handles system problems and alerts the user. For example if a printer is jammed and cannot printer, the operating system will stop the print job and alert the user with a warning message. ▸ Manages the moving of data to and from a hard disk. 17 Types of OS Interfaces ▸ The way in which users communicate with the computer is called an 'interface'. The interface is what we use to give the computer commands. There are three types of operating system interfaces: ▹ Command Line Interface (CLI) ▹ Graphical User Interface (GUI) ▹ Touchscreen Interface 18 Command Line Interface (CLI) ▸ A command line interface is an older style operating system where users type in commands using keyboard. ▸ Command Line Interface's do not make use of images, icons or graphics. All the user is sees is a plain black screen like the one to the right. ▸ Because they use no graphics they require very little computer power. ▸ There are over 270 different commands that can be entered at the command prompt. Commands have to be entered precisely without spelling mistakes or else the operating system will return an error. ▸ Remembering commands and the exact way to enter them can be difficult and so Command Line Interface Operating Systems are considered hard to use. 19 Command Line Interface (CLI) 20 Graphical User Interface (GUI) ▸ GUI's are visual (graphical) interfaces and they are more popular than CLI's because they are very easy to use. The graphics do need more computer power however. ▸ Instead of typing in commands, the user can use a mouse to point and click objects on the screen. For example: A user can erase a file by right clicking and then selecting delete. ▸ The main features of a GUI are Windows, Icons, Menus and Pointers. 21 Graphical User Interface (GUI) 22 Touchscreen Interfaces ▸ Portable devices such as mobile phones, PDA's and tablets (e.g. IPad) use interfaces similar to a GUI where icons and menus are used to input commands. ▸ However, because these devices don't have room for a mouse, the way in which the icons and menus are used is different. ▸ Touchscreen technology allows people to use their fingers to select icons and options straight from the device's screen. 23 Virtualization ▸ Virtualization creates a simulated, or virtual, computing environment as opposed to a physical environment. Virtualization often includes computer-generated versions of hardware, operating systems, storage devices, and more. ▸ A virtualization software can allow you to create several “virtual computers” (for example 3) within one. Thus, the software will create the “illusion” of generating 3 different computers, each one with its own operating system and its own resources. ▸ Refers to the creation of a virtual (rather than physical) version of a resource, such as a server, network, or storage device. 24 Hypervisors ▸ A specific type of software that enables virtualization by creating and managing virtual machines (VMs). ▸ Runs directly on the physical host machine and manages the allocation of resources to VMs. ▸ Also known as a Virtual Machine Monitor (VMM), it sits between the physical hardware and the VMs, controlling access to resources and providing isolation between VMs. ▸ Hypervisors are the underlying technology behind virtualization. 25 Hypervisors ▸ Examples: ▹ Red Hat Enterprise Virtualization (RHEV). ▹ Kernel-Based Virtual Machine (KVM). ▹ Microsoft Virtual PC. ▹ Oracle Virtual Box. ▹ VMware Workstation. ▹ Oracle VM Server for x86. ▹ CentOS Virtualization. 26 Virtualization vs. Hypervisors ▸ Virtualization is the broader concept of creating virtual resources, while hypervisor is a specific tool that enables virtualization. ▸ Virtualization can be achieved through various means, including hypervisors, containerization, and emulation, whereas hypervisor specifically refers to the software that creates and manages VMs. 27 Containerization ▸ Containerization is a lightweight alternative to full machine virtualization that involves encapsulating an application and its dependencies into a single container that can be run consistently across different environments. ▸ Working: 1. Application and dependencies are packaged into a container. 2. Container is run on a host operating system. 3. Container shares the host OS but has its own isolated user space. 4. Containers are lightweight and portable, making them easy to deploy and manage. 28 Containerization ▸ Examples of containerization platforms: 1. Docker 2. Kubernetes 3. Red Hat OpenShift 29 Cloud Computing ▸ The term cloud refers to a network or the internet. ▸ It is a technology that uses remote servers on the internet to store, manage, and access data online rather than local drives. ▸ The data can be anything such as files, images, documents, audio, video, and more. ▸ Companies that offer all the services are called cloud providers. ▸ They provide you with the ability to store and retrieve data and run applications, managing them through configuration portals. 30 Cloud Computing ▸ Platforms: ▹ Amazon Web Services (AWS) ▹ Microsoft Azure ▹ Google Cloud Platform (GCP) etc. 31 32