Operating Systems Fundamentals and Distributed Computing

Integrity checkers work by calculating checksums or cryptographic hashes of files and comparing them against stored values to detect unauthorized modifications.

Virus scanners (often referred to as virus removers or antivirus software) search for known patterns or signatures of malicious code within files.

The kernel is the core component of an operating system that manages hardware resources and provides the lowest-level interface for software.

Monitoring programs are designed to run in the background and observe system activity for suspicious patterns. Integrity checkers typically verify file signatures rather than continuously monitoring I/O operations for behavior.

In disk-based systems, the specific location where the OS core is loaded during startup is commonly referred to as the boot block or boot area. Since both terms are used interchangeably in this context, option C is the correct choice.

SISD stands for Single Instruction, Single Data. It represents the classic von Neumann architecture where one instruction is executed on one data element at a time.

A supervisor call (SVC) is a specific instruction that allows a user program to request services from the operating system kernel. It triggers a transition from user mode to supervisor mode.

MISD stands for Multiple Instruction, Single Data. This architecture involves multiple processors executing different instructions on the same data stream.

SIMD stands for Single Instruction, Multiple Data. This architecture allows a single instruction to be applied to multiple data elements simultaneously, common in vector processing.

MIMD stands for Multiple Instruction, Multiple Data. This is the most common architecture for parallel computing, where multiple processors execute different instructions on different data.

UMA stands for Uniform Memory Access. It refers to a computer architecture where all processors share a single memory system with equal access time.

NORMA stands for No Remote Memory Access. It is a distributed memory architecture where each processor has its own local memory and cannot access the memory of other processors.

NUMA stands for Non-Uniform Memory Access. In this architecture, memory access time depends on the memory location relative to the processor.

RPC stands for Remote Procedure Call. It is a protocol that allows a program to execute a procedure in a different address space, typically on another computer.

Unix was famously rewritten in the C programming language in 1973, which made it highly portable compared to earlier operating systems written in assembly.

A distributed computer system is defined as a collection of independent computers that appear to the user as a single coherent system through communication and cooperation.

A distributed operating system manages the resources and communication across a collection of autonomous computers, providing a unified interface.

Unix was developed at AT&T's Bell Labs in the late 1960s and early 1970s.

Unix was primarily developed by Ken Thompson and Dennis Ritchie at Bell Labs.

Unix development began in 1969 at Bell Labs, placing its origin in the late 1960s.

Unix was designed from the ground up to support multiple users simultaneously and uses timesharing to manage CPU resources among those users.