LinuxQuestions.org - structure independant manipulations

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structure independant manipulations

Plz give me some clues AND instances , I can't eat these expressions (UPERCAE) :

Code:

The Virtual File System

Principle

The Linux kernel contains a Virtual File System layer which is used during system calls acting on files. The VFS is an indirection layer which handles the file oriented system calls and calls the necessary functions in the PHYSICAL FILESYSTEM CODE to do the I/O. 



This indirection mechanism is frequently used in Unix-like operating systems to ease the integration and the use of several filesystem types [Kleiman 1986, Seltzer et al. 1993]. 



When a process issues a FILE ORIENTED SYSTEM CALL, the kernel calls a function contained in the VFS. This function handles the STRUCTURE INDEPENDANT MANIPUNATIONS and redirects the call to a function contained in the physical filesystem code, which is responsible for handling the structure DEPENDANT operations. Filesystem code uses the DUFFER CACHE functions to request I/O on devices.

Still at Uni, but here goes:

PHYSICAL FILESYSTEM CODE : The code (almost a BIOS) that is used to write the data to the hard disk, i.e. the assembly code that is required to write data in the proper format for the file system

FILE ORIENTED SYSTEM CALL : A call made by a program to write to disk, i.e. ifstream File; File << "text";

STRUCTURE INDEPENDANT MANIPULATIONS : Functions (I/O, I presume) that are called the same independent of the file system, i.e. File << "text"; on ReiserFS, ext2, ext3, etc.. You don't need to know the file system structure

BUFFER CACHE : Just a temporary place to put the data while waiting for other things to happed, like a previous writing to hard disk call.

Plz someone correect me if I'm wrong, still studying the computer basic operations (assembly and so forth) maybe someone knows better.

:)

BeaverusIV.
shotgun chiX0rs.