Software and Operating Systems: Types, Functions and MCQs

The correct answer is B, kernel. The kernel is the central part of the operating system and is the portion that is loaded at boot time and stays resident in main memory for as long as the computer is running. It controls the processor, allocates memory, manages files and drives the input and output devices, and every other program reaches the hardware through it.

Option A, the shell, is the outer layer of the operating system; it accepts the command typed by the user and passes it to the kernel, but it is not the core and need not always be resident. Option C, a compiler, is a language translator that converts a high level program into machine code; it is system software but not a part of the operating system core. Option D, a loader, is the program that places an executable file into main memory just before execution and then hands control to it, so it is a small utility and not the core.

The correct answer is C, firmware. Firmware is software written permanently into a read only memory chip at the time of manufacture. The BIOS on the motherboard is the standard example: it is the first code the processor executes when the machine is switched on, it runs the power on self test and it then calls the bootstrap loader, so nothing else can run before it.

Option A, application software, is written for a user task such as typing a document or preparing a spreadsheet, and it runs only after the operating system is already loaded. Option B, utility software, includes tools such as antivirus programs, disk defragmenters and file compressors; these are system software but they are stored on disk, not burnt into a chip. Option D, freeware, describes the price of a program rather than where it lives; freeware is software distributed free of cost and may be of any kind.

The correct answer is C, Round Robin. In Round Robin scheduling every ready process is given the processor for a fixed period called the time quantum, and when that period expires the process is moved to the back of the queue and the next one is served. Because each user gets a turn within a short and predictable interval, the method is exactly what a time sharing operating system needs.

Option A, First Come First Served, serves processes strictly in the order in which they arrive, so one long job at the head of the queue makes everybody wait. Option B, Shortest Job First, picks the process with the smallest burst time, which gives the lowest average waiting time but starves long processes and needs the burst time to be known in advance. Option D, priority scheduling, selects the process with the highest priority and can starve low priority work altogether.

The correct answer is A, Bell Laboratories. UNIX was developed in 1969 at Bell Laboratories by Ken Thompson and Dennis Ritchie, and it became the model for almost every multi user operating system that followed. Dennis Ritchie later created the C language, in which UNIX itself was rewritten, which is why the two names appear together in examination questions.

Option B, IBM, built its own operating systems for mainframes and later sold PC DOS, but it did not create UNIX. Option C, Microsoft, was founded in 1975, six years after UNIX appeared, and is associated with MS-DOS and Windows; its own UNIX variant, Xenix, was a later licensed product. Option D, Apple, produced the Macintosh operating system with a graphical interface; its modern system is UNIX based, but Apple did not develop the original UNIX.

The correct answer is B, deadlock. Deadlock is the state in which every process in a set is waiting for a resource that another process in the same set is holding, so none of them can ever move forward without the operating system stepping in. It needs mutual exclusion, hold and wait, no pre-emption and circular wait to occur together.

Option A, thrashing, is a different problem: it happens when the system spends nearly all its time swapping pages between disk and memory and almost none doing useful work. Option C, spooling, is a useful technique, not a fault; output meant for a slow device such as a printer is queued on disk so the processor is not held up. Option D, fragmentation, is the scattering of free memory or disk space into small unusable pieces, which wastes space but does not stop processes from running.

The correct answer is C, ext4. The extended file system family, of which ext4 is the widely used member, was written for Linux and is the default arrangement for storing and naming files on a Linux disk. It supports large volumes and large files and keeps a journal so that a disk can be recovered quickly after an unclean shutdown.

Option A, NTFS, is the New Technology File System introduced by Microsoft for the Windows NT line and used by modern Windows installations. Option B, FAT32, is the older File Allocation Table format used by earlier versions of Windows and still found on memory cards and pen drives; it cannot hold a single file larger than four gigabytes. Option D, exFAT, is also a Microsoft format, designed for flash storage to overcome that four gigabyte limit of FAT32.

The correct answer is B, warm boot. A warm boot, also called a soft boot, is the restarting of a computer that is already running, usually through the restart option of the operating system or a reset key combination. The power supply is not interrupted and some of the start-up hardware checks are skipped, so a warm boot is faster than starting from the off state.

Option A, cold boot, is the opposite case: the machine is switched on from a completely powered off state, the full power on self test runs and the operating system is loaded afresh. Option C, logging in, is only the act of proving identity with a user name and password after the operating system is already running, and it does not restart anything. Option D, formatting, prepares a disk for storing data by creating a fresh file system on it and erases what was there.

The correct answer is C, interpreter. An interpreter reads one statement of the high level program, translates it into machine code and executes it immediately before moving to the next statement. Because it never looks at the whole program in advance, it halts as soon as it meets an error, which makes debugging easy but repeated execution slow.

Option A, a compiler, translates the entire source program in one operation, produces an object file and reports all the errors of the program together, so the translated code runs faster afterwards. Option B, an assembler, is a translator too, but it works only on assembly language, converting mnemonic instructions into machine code. Option D, a linker, does not translate at all; it joins separately compiled object modules and library routines into a single executable file.

The correct answer is B, real time operating system. A real time system is judged not only by whether it gives the right answer but by whether it gives that answer inside a fixed deadline. Missile guidance, aircraft control, robotics, industrial plants and life support equipment all use such systems, where a late response is treated as a failed response.

Option A, a batch operating system, collects similar jobs and runs them one after another without any user interaction, so response time is unimportant. Option C, a time sharing system, divides processor time among many users to give each a quick turn, but it offers no hard guarantee for a particular deadline. Option D, a distributed operating system, spreads work across several connected computers so that they appear as one machine; its aim is resource sharing and reliability, not a guaranteed deadline.

The correct answer is C, word processor. A word processor is written to do a job the user wants done, namely to create, edit, format and print a document, so it belongs to application software. Spreadsheets, presentation packages, browsers, media players and billing programs fall in the same class.

Option A, a device driver, is system software; it is a small program that tells the operating system how to communicate with a particular printer, scanner or graphics card. Option B, an operating system, is the chief item of system software and provides the platform on which every application runs. Option D, an assembler, is a language translator that turns assembly language into machine code and is likewise counted as system software, not as an application.

The correct answer is B, spooling. Spooling stands for simultaneous peripheral operations on line. The operating system writes the data meant for a slow device into a queue on the disk and lets the processor go on with other work, while the device picks jobs out of that queue at its own pace. The print queue of a shared office printer is the everyday example.

Option A, paging, is a memory management method that moves fixed size blocks between disk and main memory to support virtual memory. Option C, caching, keeps recently used data in a small fast memory so that later requests are served quickly; it speeds up access but does not queue device output. Option D, swapping, moves a whole process out of main memory to disk and later brings it back, which is again memory management rather than device handling.