Operating System Concepts and History

The primary function of an operating system is to manage the computer's hardware and provide an interface for users to interact with the system.

Multiprogramming is a technique where a computer can execute multiple processes concurrently, giving the illusion of parallel execution.

False

<p>It is designed to handle a large number of small requests.</p> Signup and view all the answers

<p>A virtual machine is a software-based emulation of a physical computer system, allowing a single physical machine to host multiple operating systems or applications.</p> Signup and view all the answers

<p>A system call is a software interface that allows user programs to request services from the operating system kernel, providing a controlled and structured way for programs to access system resources.</p> Signup and view all the answers

<p>A shell is a command-line interpreter that provides a user interface for interacting with the operating system. It allows users to execute commands, manage files, and control system behavior.</p> Signup and view all the answers

<p>A monolithic operating system has all its components compiled into a single executable, making it a less structured approach. A layered system, on the other hand, divides its components into distinct layers, each with specific functionalities and interfaces.</p> Signup and view all the answers

<p>Threads are easier and faster to create and destroy than processes.</p> Signup and view all the answers

<p>A race condition occurs when the outcome of a program is dependent on the unpredictable timing of multiple processes accessing and modifying shared resources. This can lead to unexpected and incorrect results if the sequences of actions are not properly synchronized.</p> Signup and view all the answers

<p>Resource allocation graph contains a cycle.</p> Signup and view all the answers

<p>A safe state in a system is a state where all the processes can complete their execution without causing a deadlock, even if resource allocation requests are made in a specific order. The operating system aims to maintain the system in a safe state to avoid deadlocks.</p> Signup and view all the answers

<p>A page table acts as a mapping between virtual memory addresses used by a program and the corresponding physical memory addresses where the actual data is stored. It allows the system to efficiently manage memory allocation and address translation.</p> Signup and view all the answers

<p>A page fault occurs when a process tries to access a virtual memory page that is currently not loaded into physical memory. This triggers an interrupt, prompting the operating system to retrieve the missing page from secondary storage and load it into physical memory.</p> Signup and view all the answers

<p>It is not suitable for systems with strong locality of reference.</p> Signup and view all the answers

<p>LRU focuses on evicting the page that has not been used recently, assuming that recently used pages are likely to be accessed again soon. In contrast, LFU aims to evict the page that has been referenced the least often in the past, regardless of how recently it was used.</p> Signup and view all the answers

<p>The primary goal of a disk scheduling algorithm is to optimize the order in which disk I/O requests are served, aiming to minimize the overall disk access time and maximize throughput by reducing the time spent on seek operations and improving the efficiency of disk bandwidth utilization.</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>Shortest Seek Time First (SSTF)</p> Signup and view all the answers

<p>Cylinder skew is a technique used during disk formatting to optimize read operations by strategically offsetting the starting position of sector 0 on each track, ensuring that the disk head can access multiple tracks in a continuous sequence without waiting for a full rotation.</p> Signup and view all the answers

<p>A device driver is a software module that provides the operating system with a specific interface for communicating with and controlling a particular type of I/O device.</p> Signup and view all the answers

<p>I/O port approach uses dedicated I/O ports to communicate with device registers, requiring special I/O instructions to access. Memory-mapped I/O maps device registers into the system's memory space, allowing the CPU to access them using regular memory read/write instructions. Memory-mapped I/O is typically more efficient and flexible, as it doesn't require separate I/O instructions and allows device drivers to be written completely in a high-level language, while I/O port approach often requires assembly code for accessing device registers.</p> Signup and view all the answers

<p>DMA enables the transfer of data directly between an I/O device and main memory without requiring the involvement of the CPU, allowing the CPU to perform other tasks while data transfers are in progress, significantly improving I/O performance and reducing CPU overhead.</p> Signup and view all the answers

<p>An interrupt handler is a software routine responsible for responding to interrupt signals generated by I/O devices or other system events. Its primary function is to handle the interrupt appropriately, perform the necessary actions, and restore the system to a state where it can continue its normal operations.</p> Signup and view all the answers

<p>A device driver is a software module that provides the operating system with a specific interface for communicating with and controlling a particular type of I/O device.</p> Signup and view all the answers

<p>The two main types of file access methods are sequential access and random access. Sequential access allows data to be accessed in a linear order, starting from the beginning. Random access allows data to be accessed directly at any specific location within the file.</p> Signup and view all the answers

<p>The primary goals of I/O software are to provide device independence, uniform naming, error handling, synchronous or asynchronous data transfers, buffering mechanisms, and support for both sharable and dedicated devices.</p> Signup and view all the answers

<p>A file system is responsible for organizing, storing, and managing files on a storage device (like a hard disk). It provides a hierarchical structure for storing files, allows users to access and manipulate files efficiently, and ensures data integrity.</p> Signup and view all the answers

<p>Contiguous allocation assigns a continuous block of disk space to each file, while linked list allocation stores file blocks in a linked list, allowing for flexible allocation and potentially minimizing disk fragmentation. Contiguous allocation offers faster access but can lead to external fragmentation, while linked list allocation provides more efficient space utilization but may require more disk accesses for random access.</p> Signup and view all the answers

<p>A directory is a special file that stores information about other files and subdirectories within the file system. It acts as a hierarchical index, facilitating user navigation and access to the files and subdirectories. Each directory entry typically contains the name, attributes, and location (disk address) of the corresponding file or subdirectory.</p> Signup and view all the answers

<p>An absolute path name specifies the full path from the root directory to a file, starting with a forward slash (/) and including the names of all parent directories. A relative path name specifies the path to a file relative to the current working directory, using the names of parent directories relative to the current directory. For instance, <code>/home/user/documents/file.txt</code> is an absolute path, while <code>documents/file.txt</code> is a relative path if the current working directory is <code>/home/user</code>.</p> Signup and view all the answers

<p>RAID (Redundant Array of Independent Disks) is a technique that combines multiple physical disks into a logical unit, improving performance, reliability, and fault tolerance. It distributes data and parity information across multiple disks, allowing for faster data transfers, data recovery from disk failures, or even increased storage capacity.</p> Signup and view all the answers

<p>RAID 0</p> Signup and view all the answers

<p>A process is an independent execution environment with its own dedicated address space and resources, such as memory and open files. A thread, on the other hand, is a lighter-weight execution unit that shares the address space and resources of its parent process. Multiple threads within a process can execute concurrently, sharing the same resources.</p> Signup and view all the answers

<p>A page fault occurs when a process tries to access a virtual memory page that is not currently loaded in physical memory. This triggers an interrupt, prompting the operating system to retrieve the missing page from secondary storage and load it into physical memory.</p> Signup and view all the answers