Page 387 - DCAP103_Principle of operating system

Principles of Operating Systems

Notes Program
/* Open files for input and output */
inhandle = CreateFile(“data”, GENERIC_READ, 0, NULL, OPEN_EXISTING, 0, NULL);
outhandle = CreateFile(“newf”, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL, NULL);
/* Copy the file. */
do{
s = ReadFile(inhandle, buffer, BUF_SIZE, &count, NULL);
if(s && count > 0) WriteFile(outhandle, buffer, count, &ocnt, NULL);
} while(s > 0 && count > 0);
/* Close the files. */
CloseHandle(inhandle);
CloseHandle(outhandle);

Windows 2000 NTFS is a hierarchical file system, similar to the UNIX file system. The separator
between component names is \ however, instead of /, a fossil inherited from MS-DOS. There
is a concept of a current working directory and path names can be relative or absolute. Hard
and symbolic links are supported, the former implemented by having multiple directory entries,
as in UNIX, and the latter implemented using reparse points (discussed later in this unit). In
addition, compression, encryption, and fault tolerance are also supported. These features and
their implementations will be discussed later in this unit.
The major directory management API functions are given in Figure 13.4, again along with their
nearest UNIX equivalents. The functions should be self explanatory.

Figure 13.4: The Principal Win32 API Functions for Directory Management. The Second
Column Gives the Nearest UNIX Equivalent, When One Exists

Win32 API function UNIX Description
CreateDirectory mkdir Create a new directory

RemoveDirectory rmdir Remove an empty directory
FindFirstFile opendir Initialize to start reading the entries in a directory
FindNextFile readdir Read the next directory entry
MoveFile rename Move a file from one directory to another

SetCurrentDirectory chdir Change the current working directory

13.2.3 Implementation of the Windows 2000 File System
NTFS is a highly complex and sophisticated file system. It was designed from scratch, rather
than being an attempt to improve the old MS-DOS file system. Below we will examine a number
of its features, starting with its structure, then moving on to file name lookup, file compression,
and file encryption.
13.2.4 File System Structure

Each NTFS volume (e.g., disk partition) contains files, directories, bitmaps, and other data
structures. Each volume is organized as a linear sequence of blocks (clusters in Microsoft’s

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