Which type of software is permanently stored on a chip and is required before any other program can run?

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, 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.