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OPERATING SYSTEMS- 1
What is Operating System? History and
Evolution of OS, Basic OS functions, Resource Abstraction, Types
of Operating Systems– Multiprogramming Systems, Batch Systems,
Time Sharing Systems; Operating Systems for Personal Computers,
Workstations and Hand-held Devices, Process Control & Real time
Systems.
1.What is Operating System? An Operating System (OS) is an interface between a user and computer hardware. An operating system is a system 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. Generally, a Computer System consists of the following components:
- Computer Users are the users who use the overall computer system.
- Application Softwares are the softwares which users use directly to perform different activities. These softwares are simple and easy to use like Browsers, Word, Excel, different Editors, Games etc.
- System Softwares are the softwares which are more complex in nature and they are more near to computer hardware. Operating Systems (Microsoft Windows, macOS, and Linux).
- Computer Hardware includes Monitor, Keyboard, CPU, Disks, Memory, etc. Objectives of Operating System
- To make the computer system convenient to use in an efficient manner.
- To hide the details of the hardware resources from the users.
- To provide users a convenient interface to use the computer system.
In today’s world, we use Microsoft Windows as our standard operating system. Advantages of Operating System:
- Allows multiple users to access the computer simultaneously
- Organizes and manages files
- Provides a platform for software applications
- Enables communication between computers and peripheral devices. Disadvantages of Operating System:
- Can be expensive
- Can require significant hardware resources
- Vulnerable to malicious software attacks. 3. Explain the Functions of operating System? An Operating System (OS) is an interface between a user and computer hardware. Functions of Operating System
1. File Management An operating system’s (OS) primary function is to manage files and folders. Operating systems are responsible for managing the files on a computer. This includes creating, opening, closing, and deleting files. The operating system is also responsible for organizing the files on the disk. 2. Device management Operating systems provide essential functions for managing devices connected to a computer. These functions include allocating memory, processing input and output requests, and managing storage devices. This device could be a keyboard, mouse, printer, or any other devices you may have connected. 3. Process management The operating system’s responsibility is to manage the processes running on your computer. This includes starting and stopping programs, allocating resources, and managing memory usage. How do Operating systems manage all processes? Each process is given a certain amount of time to execute, called a quantum. Once a process has used its quantum, the operating system interrupts it and provides another process with a turn. This ensures that each process gets a fair share of the CPU time.
- Memory management One of the most critical functions of an operating system is memory management.
- Allocating memory to store programs.
- Deciding the amount of memory that should be allocated to the program.
- Memory distribution while multiprocessing. 5. Job Accounting An operating system’s (OS) job accounting feature is a powerful tool for tracking how your computer’s resources are being used. This information can help you pinpoint and troubleshoot any performance issues and identify unauthorized software installations. 6. Security For security, modern operating systems employ a firewall. A firewall is a type of security system that monitors all computer activity and blocks it if it detects a threat.
Advantages of Batch Operating System:
- It is very difficult to guess or know the time required for any job to complete.
- Multiple users can share the batch systems
- The idle time for the batch system is very less
- It is easy to manage large work repeatedly in batch systems Disadvantages of Batch Operating System:
- The computer operators should be well known with batch systems
- Batch systems are hard to debug
- It is sometimes costly
- The other jobs will have to wait for an unknown time if any job fails Examples of Batch based Operating System: Payroll System, Bank Statements, etc. 2. Time-Sharing Operating Systems Each task is given some time to execute so that all the tasks work smoothly. Each user gets the time of CPU as they use a single system. These systems are also known as Multitasking Systems. The task can be from a single user or different users also. The time that each task gets to execute is called quantum. After this time interval is over OS switches over to the next task.
Advantages of Time-Sharing OS:
- Each task gets an equal opportunity
- CPU idle time can be reduced
- Resource Sharing Disadvantages of Time-Sharing OS: - Data communication problem - Security Risks: With multiple users sharing resources, the risk of security breaches increases. Examples of Time-Sharing OSs are: Multics, Unix, etc. 3. Distributed operating system A distributed operating system is an operating system that is designed to operate on a network of computers. Distributed systems are usually used to distribute software applications and data. Distributed systems are also used to manage the resources of multiple computers. Multiple computers are connected via a single communication channel. Every system have its own processor and memory. Resources like disk, computer, CPU, network interface, nodes, etc are shared among different computer at different locations. It increases data availability in the entire system. Advantages - It is more reliable as a failure of one system will not impact the other computers or the overall system. - All computers work independently. - Resources are shared so there is less cost overall. - The system works at a higher speed as resources are shared
Examples of Network Operating System are: Microsoft Windows Server 2003, Microsoft Windows Server 2008, UNIX, Linux, Mac OS X etc.
5. Real time OS A real time operating system time interval to process and respond to inputs is very small. Examples: Military Software Systems, Space Software Systems are the Real time OS example. The quick response of the process is a must in real-time operating systems. There is no chance of any delay in completing any process because a little delay can cause several dangerous issues. Advantages of Real-time operating system: o In a Real-time operating system, the maximum utilization of devices and systems. o Easy to layout, develop and execute real-time applications under the real- time operating system. Disadvantages of Real-time operating system: o Real-time operating systems have complicated layout principles and are very costly to develop. o Real-time operating systems are very complex and can consume critical CPU cycles. 6. Multiprocessor OS This operating system is commonly found on computer systems with more than one CPU. Multiprocessor systems improve system performance by allowing the execution of tasks on multiple processors simultaneously.
Advantages
- It allows the system to run multiple programs simultaneously.
- Beneficial for tasks that need to use all of the processor’s resources, such as games, scientific calculations, and financial simulations. Disadvantages
- They require additional hardware, such as processors and memory, making a system more expensive. 7. Multi-programming OS
- The operating system which can run multiple processes on a single processor is called a multiprogramming operating system. Advantages
- It may help to run various jobs in a single application simultaneously.
- The resources are utilized smartly.
5. Explain Resource abstraction? - An abstraction is software that hides lower level details and provides a set of higher- level functions - Resource include Central processing unit (CPU), memory, file storage, I/O devices and network connections. - The fundamental operation of the operating system is to abstract the hardware to the programmer and user. The OS provides generic interfaces to services provided by the underlying hardware - Resource abstraction is the process of “hiding the details of how the hardware operates, thereby making computer hardware relatively easy for an application programmer to use. - Such an abstraction saves the programmer from needing to learn the details of bother hardware interfaces. 6. Explain Operating system for personal computers? - Most of the OS relating to personal computers and other gadgets started in 4thGeneration (1980s) - The cost of personal computers was very high at that time, there were small fractions of mini computers costs. - A major factor related to creating personal computers was the birth of Microsoft and the windows Operating System - Microsoft created the first window OS in 1975. - Personal computers OS provides a good interface to a single user. - We can say that our laptops, computer systems, tablets etc., are your personal computers and the OS such as windows 7, Windows 10, android etc., are personal computer Operating System. - We can use our personal computer OS for our personal purposes, for Example, to chatting with your friends using some social media sites, accessing internet, making some projects or any other; designing web sites, programming something, watching videos and movies and many more.
7. Write about Workstations and Hand-held Devices?
- Workstations are computers that are specifically configured to meet the most demanding technical computing requirements.
- To be considered a workstation, systems must include key capabilities related to performance, reliability, data integrity, scalability, and expandability.
- Workstations are most frequently used in creative, engineering, scientific, and financial services industries. Features of a Workstation
- Specialized Performance
- Reliability
- Data integrity 4.scalability 5.expandability. Hand-held Devices: A handheld device is a pocket-sized computing device with a display screen and input/output interface like an external or touch screen keyboard. A mobile device is a general term for any type of handheld computer. These devices are designed to be extremely portable, and they can often fit in your hand. Example: smartphones Smartphones A smartphone is a more powerful version of a traditional cell phone. In addition to the same basic features—phone calls, voicemail, text messaging—smartphones can connect to the Internet over Wi-Fi or a cellular network (which requires purchasing a monthly data plan ). This means you can use a smartphone for the
set point. In this example, the set point is the temperature setting on the thermostat and the heater turns on and off to maintain temperature. Hence, this simplest form of process control is called on/off or deadband control. Real time system
- In real time system, large number of events, mostly external to the computer system, must be accepted and processed in a short time or within certain deadlines.
- Such applications are industrial control, telephone switching equipment, flight control.
- Realtime OS are 3 types o Hard Realtime OS: These OS guarantee that critical tasks be completed within a range of time. o Soft Realtime OS: This OS provides some relaxation in the time limit. o Firm Realtime OS: RTOS of this type have to follow deadlines as well. Inspite of its small impact, missing a deadline can have unintended consequences.
