Things to note about Functions in C plus plus (C++)

While passing arguments, the function creates copies of the arguments passed to it. This type of passing arguments is called passing by value. We can pass structure as arguments. We can also return a structure. Useful while returning multiple values. Passing by reference : e.g. void intfunc(float& a, int& b); We can also pass structures … Read more

Things to note about Structure in C plus plus (C++)

Initializing structure structure_name variable_name = {value1,value2,…,valueN}; Initializing nested structure structure_name variable_name = { {value1, value2},{value3,value4}}; A structure can be nested up to any depth in theory. Structure can hold data and functions (In c they can only hold data) An enum declaration defines the set of all names that will be permissible values of the … Read more

Kernel Architecture of Various Popular Operating Systems.

Overview : UNIX : Layered Architecture Linux : Monolithic Architecture Windows : Hybrid Architecture (Microkernel + Layered) Mach : Microkernel Architecture. UNIX KERNEL ARCHITECTURE : Unix OS considers files and processes as the most important entities.   Unix offers a shell that acts as a command interpreter between the user and the kernel. The relevant … Read more

Virtual Machine Architecture

Virtualization can be defined as the process of creating multiple copies of an object. A virtual machine is a virtualization of a machine. The software that creates multiple copies of a machine is called a virtual machine monitor (VMM) or a hypervisor. Each virtual machine have its own OS called ‘guest OS’ and the OS … Read more

Types of Operating System Architecture Models

There are mainly three types of operating system architecture models : Monolithic OS : Used in older but smaller operating systems. Operating system is divided into procedures. Each procedure have a particular task and all procedures have common data structures and system tables. Each procedure can call other procedures. Resulting in high degree of inter-process … Read more

Processor Execution Modes

There are mainly three types of OS architecture models : Monolithic OS Layered OS Client-server or microkernel OS In every model, there are two modes of processor execution : the user mode and the system mode. Application programs run in the user mode whereas the operating system runs in the system mode. The system mode … Read more

Important Things to Note About Loops and Decision in C++

Before C++ true and false were represented as 1 and 0 respectively. But C++ uses both. Other than 0 all values represent true. Library function exit() : exit(0) : Normal Exit exit(other numerical value) : Error / Abnormal exit. This function is present in ‘process.h’ Library function getche(): This function is present in conio.h No … Read more

C++ Basics Which May Have Been Skipped In Class

White-space is completely ignored by compiler : Not True. There are few restrictions apply to this rule. e.g. Preprocessor directives must be in same line. ‘cout’ could not be broken. Cout, Cin are objects : These are overloaded. Cout – ‘<<‘ (Put to or insertion operation) and ‘>>’ (extraction or get operator). Directives : Preprocessor … Read more

Design Goals of Operating Systems.

The design goals of operating systems are : POSIX Compliance : POSIX (Portable operating system interface bases on Unix) is an IEEE standard 1003.1-1988. This standard helps in bringing comptibility among the various OSes. Extensibility : It is the ability of an OS to grow and change over time, according to the changing requirements of … Read more

Types of Operating Systems.

Various types of operating systems are : Single User OS : There is only one user and only his/her programs in the system memory. So there are not security issues too. This type of OS is called a ‘single user mono programming‘. e.g. DOS (Disk operating system) Multi-User OS : System is one but it … Read more