Types of Operating Systems and Their Functions
- What is Operating System? Explain the Abstract View of the Components of a Computer System.
- An operating system (OS) is a collection of software that manages computer hardware resources and provides various services for computer programs. It acts as an intermediary between the user of a computer and the computer hardware
- Explain Different Types of OS.
Mainframe Operating Systems
- The operating system found in those room-sized computers which are still found in major corporate data centers. These computers differ from personal computers in terms of their I/O capacity.
- They typically offer three kinds of services: batch, transaction processing, and timesharing.
- Batch operating system
- Transaction processing
- Time sharing
- An example mainframe operating system is OS/390 and a descendant of OS/360.
Server Operating Systems They run on servers, which are very large personal computers, workstations, or even mainframes.
- They serve multiple users at once over a network and allow the users to share hardware and software resources.
- Typically, server operating systems are Solaris, FreeBSD, Linux, and Windows Server 200x.
Multiprocessor Operating Systems
- An increasingly common way to get major group computing power is to connect multiple CPUs into a single system. Depending on precisely how they are connected and what is shared, these systems are called parallel computers, multicomputers, or multiprocessors. The operating systems used in this system are multiprocessor operating systems.
Personal Computer Operating Systems
- The next category is the personal computer operating system. All modern computers support multiprogramming, often with more than one program started up at boot time. Their job is to provide good support to a single user.
- They are widely used for word processing, spreadsheets, and Internet access. Common examples of personal computer operating systems are Linux, FreeBSD, Windows Vista, and Macintosh operating system. Handheld Computer Operating Systems
Embedded Operating Systems
- Embedded systems run on the computers that control devices that are not generally thought of as computers and which do not accept user-installed software. The main property which distinguishes embedded systems from handhelds is the certainty that no untrusted software will ever run on it.
- So, there is no need for protections between applications, leading to some simplifications.
Real-Time Operating Systems
- These systems are characterized by having time as a key parameter.
- An example of a real-time system is e-Cos.
Smart Card Operating Systems
- The smallest operating systems run on smart cards, which are credit card-sized devices containing a CPU chip. They have very severe processing power and memory constraints.
- Some of them can handle only a single function such as electronic payments, but others can handle multiple functions on the same card. Often these are proprietary systems.
- Explain Different Types of Tasks Done by OS. OR
Write Different Services Provided by Operating System.
Access to I/O Devices
- Each I/O device requires its own set of instructions for operations.
- Operating system provides a uniform interface that hides these details, so the programmer can access such devices using simple reads and writes.
Memory Management
- It keeps track of which parts of memory are in use and free memory.
- It allocates the memory to programs when they need it.
- It de-allocates the memory when programs finish execution.
Controlled Access to File
- In the case of file access, the operating system provides a directory hierarchy for easy access and management of files.
- OS provides various file handling commands using which users can easily read, write, and modify files.
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Error Detection and Responseδ
- Various types of errors can occur while a computer system is running, which includes internal and external hardware errors. For example, memory error, device failure error, and software errors such as arithmetic overflow.
- In case, the operating system must provide a response that clears the error condition with the least impact on running applications. Accounting
Protection & Security
- Operating systems provide various options for protection and security purposes.
- It allows the users to secure files from unwanted usage.
Virtual Machine
- The initial releases of OS/360 were strictly batch systems. But many users wanted to be able to work interactively at a terminal, so OS designers decided to write timesharing systems for it.
Figure 1-7. The Structure of VM/370 with CMS.
- The heart of the system, known as the virtual machine monitor, runs on the bare hardware and does the multiprogramming, providing not just one but several virtual machines to the next layer up.
- Each virtual machine is identical to the true hardware; each one can run any OS that will run directly on the bare hardware.
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