Linux Architecture Linux Architecture Kernel The other component
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Linux Architecture
Linux Architecture
Kernel • The other component of the Linux O. S is the kernel which makes a direct interface with the hardware components. • The kernel make creation and deletion of processes, schedule the memory management and I/O management of the processor. • It provides mechanism for inter process communication.
Shell Interface
Shell Interface 1 Shell is the command interpreter which reads the program we type at terminal, line by line and perform the required operations. 2. The shell is the part of Linux O. S that acts as an intermediary between user and the O. S. 3. Linux system provides every user its own copy of shell program which makes him work freely without any interference of other users.
User Space • The User Space is the space in memory where user processes run. • The system prevents one process from interfering with another process. • Only Kernel processes can access a user process
Kernel Space • The kernel Space is the space in memory where kernel processes run. • The user has access to it only through the system call.
System Calls • System call is the mechanism used by an application program to request service from the operating system. • A user process becomes a kernel process when it executes a system call.
Linux Process Management • Process is a program in execution. • The Linux OS is a time-sharing system. Every process is scheduled to run for a period of time (time slice). • Kernel creates, manages and deletes the processes
Process Management
Computer Memory Management
Memory Management • Memory allocations in the Linux kernel occur either statically or dynamically. • Linux’s physical memory-management system deals with allocating and freeing pages, groups of pages, and small blocks of memory. • The page allocator allocates and frees all physical pages; it can allocate ranges of physically-contiguous pages on request.
Virtual Memory • The VM system maintains the address space visible to each process: It creates pages of virtual memory on demand, and manages the loading of those pages from disk or their swapping back out to disk as required.