1) What is the first step in problem-solving? A) Writing code B) Debugging C) Understanding the problem D) Optimizing the solution Answer: C 2) Which of these is not a step in the problem-solving process? A) Algorithm development B) Problem analysis C) Random guessing D) Testing and debugging Answer: C 3) What is an algorithm? A) A high-level programming language B) A step-by-step procedure to solve a problem C) A flowchart D) A data structure Answer: B 4) Which of these is the simplest data structure for representing a sequence of elements? A) Dictionary B) List C) Set D) Tuple Answer: B 5) What does a flowchart represent? A) Errors in a program B) A graphical representation of an algorithm C) The final solution to a problem D) A set of Python modules Answer: B 6) What is pseudocode? A) Code written in Python B) Fake code written for fun C) An informal high-level description of an algorithm D) A tool for testing code Answer: C 7) Which of the following tools is NOT commonly used in pr...
OPERATING SYSTEM:
An Operating System (OS) is an interface between a computer user and computer hardware. An operating system is a software which performs all the basic tasks like file management, memory management, process management, handling input and output, and controlling peripheral devices such as disk drives and printers.
Goal of an operating system:
* Operating system executes user program and easily solve user problem.
* Operating system makes the computer system easy to use.
* Operating system use the computer hardware in an effective manner.
Structure of Computer system:
Computer system can be divided into four components.
*Hardware: Includes the physical parts of a computer and related devices. Such as CPU, memory, I/O devices.
* Operating system: A program that acts as an intermediate between computer user and the computer hardware.
* Application programs: It is used to solve the computing problem of the user using system resources.
Eg: Word processors, compilers, web browsers, database systems,
video games
* Users: The users of the system refer to the people who use computers to perform their jobs, like desktop operators.
Four Components of a Computer System
* A process is a set of activities used to produce a result. It is a unit of work within the system. Program is a passive entity, process is an active entity.
* Process needs resources to complete its task. The resources include CPU, memory, I/O, files.
* Initialization data: An operating system or application program is installed with default or user-specified values that determine certain aspects of how the system or program is to function.
* Process termination requires rescue of any reusable resources.
* Single-threaded process has one program counter specifying location of next instruction to execute
* Process executes instruction one after another until completion.
* Multi-threaded process has one program counter per thread
* Typically system has many processes, some user, some operating system running simultaneously on one or more CPUs.
* Simultaneous by multiplexing the CPUs among the processes / threads.
Process management activity:
The operating system is responsible for the activities in connection with process management:
* Creating and deleting both user and system processes.
* Postponing and resuming processes.
* Providing mechanisms for process coincide.
* Providing mechanisms for process communication.
* Providing mechanisms for deadlock handling.
Memory management:
*The process of controlling and coordinating computer memory.
* Running programs to optimize the overall performance of the system.
* It manages primary memory.
* It helps processes to move back and forward between the main memory and execution disk.
* It helps OS to keep track of every memory location, irrespective of whether it is allocated to some process or it remains free.
Memory management activities
*Keeping track of which parts of memory are currently being used and by whom
* Deciding which processes and data to move in and out of memory
* Used to allocate and deallocate the memory space.
Storage Management:
* OS provides same, logical view of information storage.
* Abstracts physical properties (files) to logical storage units(segments).
* Each medium is controlled by device (i.e., disk drive, tape drive)
* Differing properties include access speed, capacity, data-transfer rate, access method.
* File-System management.
* Files are arranged into directories.
* Access control is used to who can access the resources.
OS activities include:
* Creating and deleting files and directories.
* Simple to manipulate files and directories.
* Processing files onto secondary storage devices.
* Backup files onto stable storage media.
Mass-Storage Management:
* Disks are used to store data that does not fit in main memory or data that must be kept for a “long” period of time.
* Proper management is the main importance.
* Entire speed of computer operation depends on disk subsystem and its algorithms.
Mass storage activity:
* Free-space management
* Allocating storage
* Scheduling disk
* Some storage does not process speed.
* Tertiary storage includes optical storage, magnetic tape
* Storage must be managed.
* Varies between WORM (write-once, read-many-times) and RW (read-write)