The period of first generation was 1946-1959. The computers of first generation used vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing Unit).Continue Reading
All of the operations involving processes are controlled by a portion of the O.S. variously called its Nucleus, Core, or Kernel.Continue Reading
When an interrupt occurs, the operating system saves the status of the interrupted process, and routes control to the appropriate first level interrupt handler. This is accomplished by a technique called Context Switching.Continue Reading
Dijkstra abstracted the key notions of mutual exclusion in his concept of semaphores. A Semaphore is a protected variable whose value can be accessed and altered only by the operations P and V and an initialization operation we shall call semaphore initialize.Continue Reading
When a process is accessing shared modifiable data, the process is said to be in a critical section (or critical region).Continue Reading
The manifestation of a process in an operating system is represented by a data structure known as a process control block (PCB) or process descriptor.Continue Reading
Inter-process communication (IPC) is a set of programming interfaces that allow a programmer to coordinate activities among different program processes that can run concurrently in an operating system.Continue Reading
Process Synchronization means sharing system resources by processes in such a way that, Concurrent access to shared data is handled thereby minimizing the chance of inconsistent data.Continue Reading
Mutual Exclusion is way of making sure that if one process is using a shared modifiable data, the other processes will be excluded from doing the same thing.Continue Reading
A process is a program in execution. For example, a running “xyz process” is a single process of the operating system.Continue Reading
The process scheduling is the activity of the process manager that handles the removal of the running process from the CPU and the selection of another process on the basis of a particular strategy.Continue Reading
As a process executes, it changes state. The state of a process is defined as the current activity of the process.Continue Reading
A process is a program in execution. The execution of a process must progress in a sequential fashion.Continue Reading
The General Motors Research Laboratories implemented the first operating system in the early 1950’s for their IBM 701.Continue Reading
The primary function of the BIOS is to load and start an operating system. When the PC starts up, the first job for the BIOS is to initialize and identify system devices such as the video display card, keyboard and mouse, hard disk, CD/DVD drive and other hardware.Continue Reading
An Operating Systems provides services to both the users and to the programs.
It provides programs, an environment to execute.
It provides users, services to execute the programs in a convenient manner.
A COM file is a type of simple executable file. On the Digital Equipment operating systems of the 1970s, .COM was used as a filename extension for text files containing commands to be issued to the operating system (similar to a batch file).Continue Reading
Real Time operating System, Batch operating system, Time-sharing operating systems, etc.Continue Reading
An operating system and Graphical User Interface (GUI) created by Microsoft and found on most computer systems.Continue Reading
Though UNIX was a powerful operating system available, but it was not suitable for 8-bit 8086 microprocessor based Personal Computers. So there was a need for a small operating system that could work in 640K memory (RAM). DOS, a 16-bit command-line operating system was a variant of CP/M (Control Program/Monitor) which ran for the first time on IBM-PC in 1981.Continue Reading
An Operating System is a set of programs that controls and coordinates the use of computer hardware among various application programs. It provides an environment within which user can execute programs. A computer can be divided into four components: the hardware, the operating system, the applications programs, the users.Continue Reading