Vinay's Blog Rants

Process :   Is an executing instance of an application . They run in separate memory space unlike threads. To put it in simple terms, we write our computer programs in a text file and when we execute this program, it becomes a process which performs all the tasks mentioned in the program. Example: when you double-click the Microsoft Word icon, you start a process that runs word. Threads :   are path of execution within a process . Threads within the same process runs in a shared memory space . ----------------------------------------------------------------- ----------------------------------------------------------------- U may have heard process is heavy weight . actually when process is created Operating system creates a PCB (process control block) which includes may things like  process id - Unique identification for each of the process in the operating system. pointers  - A pointer to parent process. state -The current state...

Hardware : It is a collection of electronic equipment’s which are assembled together to  work as a single unit. This arrangement is used to direct the flow of electricity in a desired manner. Software : Software’s are nothing but programs which are used to generally perform advance tasks with the same set of hardware.  For example:  every mobile phone have flash for taking photos in the dark places. But someone developed a software to keep the light on continuously, this gave us flash light support in our mobiles but remember the hardware was still the same. Firmware :   Firmware is a set of most basic instructions that can be passed to the hardware for its basic functioning . In other words, these are the instructions which sits between the software & the hardware. Yes they're stored on ROM to prevent unauthorized alterations. Recall the example of flashlight, the basic instructions to the hardware were to open the light for the purpose of flash onl...

1) What is Kernel? A kernel is the central part of an Operating system. It manages the tasks of the computer and the hardware. A kernel is the part of the operating system that mediates access to system resources. It's responsible for enabling multiple applications to effectively share the hardware by controlling access to CPU, memory, disk I/O, and networking. An operating system is the kernel plus applications that enable users to get something done (i.e. compiler, text editor, window manager, etc.).       

                MEMORY MANAGEMENT Background: Memory consists of a large array of words or bytes, each with its own address. The CPU fetches instructions from memory according to the value of the program counter. These instructions may cause additional loading from and storing to specific memory addresses. Just as processes share the CPU, they also share physical memory Memory management is subdividing memory to accommodate multiple processes.  Memory needs to be allocated to ensure a reasonable supply of ready processes to consume available processor time. Memory Allocation: There are two types of memory allocation techniques: Contiguous. Non - Contigous. 1.Contiguous Memory Allocation: Fixed size partitioning . Dynamic Partitioning . Fixed size partitioning -  (Causes internal fragmentation) : Each partition contain exactly one process. Degree of multiprogramming bound by # of partitions...