19-10-2012, 12:51 PM
Distributed operating System
Distributed operating.ppt (Size: 973 KB / Downloads: 37)
Unix i-node Structure
An index node is a block that holds pointers to all the blocks used by a File.
In the past, the structure may have consisted of eleven or thirteen pointers.
Modern file systems use fifteen pointers.
Unix inode pointer structure
Twelve pointers that directly point to blocks of the file's data (direct pointers)
One singly indirect pointer (a pointer that points to a block of pointers that then point to blocks of the file's data)
One doubly indirect pointer (a pointer that points to a block of pointers that point to other blocks of pointers that then point to blocks of the file's data)
One triply indirect pointer (a pointer that points to a block of pointers that point to other blocks of pointers that point to other blocks of pointers that then point to blocks of the file's data)
Vector clocks:
A vector clock system is a mechanism that associates timestamps with events (local states) such that comparing two events' timestamps indicates whether those events (local states) are causally related (and, if they are, which one comes first).