A+ Certification may be obtained by passing A+
Essentials exam, and A+ Practical Applications exam Note that a candidate
needs to pass both the exams to obtain the certification. Linux is not
included in the A+ Certification exam, as it has an exam of
its own (Linux+ Certification), offered by CompTIA. A brief notes on important
concepts of A+ Certification Operating Systems is given in the following sections.
With the latest release of A+ objectives, several topics in Windows Vista,
Windows 7, Wireless networking and Security have been added.
1.1 Major Operating System components, and interfaces
1.3 Frequently used command line functions
1.4 Creating and Managing Disks, Directories, and Files
1.5 Some Operating System Utilities
1.2 Major System Files, and their purpose:
The MSDOS.SYS file is a hidden system file created on the root of the boot
drive. To edit this file, type edit msdos.sys. The PC boot environment can be
changed by changing the file contents. Given below is a typicalMSDOS.SYS file:
Below is a sample MSDOS.SYS File
;The following lines are required for compatibility with other programs.
;Do not remove them (MSDOS.SYS needs to be >1024 bytes).
An AUTOEXEC.BAT file contains DOS commands that are executed automatically
when a PC boots. The file is usually located in the root directory of the hard
drive of the computer. The AUTOEXEC.BAT file is used to set defaults and to run
programs that should be executed during startup.
Use the PROMPT command to alter the default DOS prompt. The above command
makes the DOS prompt display the current path and drive, and is very useful.
It does: The file contains internal command set and error messages
Default Attributes: Nil
Is it required for OS Start up: YES
Responsible for displaying the command prompt in a DOS based computer.
It does: Loads low level device drivers and does performance tuning
Default Attributes: Nil
Is it required for OS Start up: NO
EMM386.EXE allows access to Upper Memory Area. Please note that the
conventional memory of 1 MB is divided into 1. Lower Memory Area 640 KB, and
2. Upper Memory Area 384KB (1024KB-640KB).
1. HIMEM.SYS must be loaded before
2. HIMEM.SYS is used to address the extended
The executable file located in the windows directory used to load Microsoft
Used with Microsoft Windows 9x to initialize system settings
for the computer, such as the fonts, keyboard, language and other settings.
The system.ini file is located in the C:\windows directory. Users looking to
view or edit the system.ini file can use the sysedit or msconfig
Windows NT 4.0, 2000, XP, or later operating systems do not have a
system.ini. Instead, the initialization setting for these OSes are stored in
the system registry.
The Microsoft Windows 3.x and 9x initialization file located in the
C:\Windows directory. The win.ini file is used to load various settings each
time Windows boots; for example, the communications drivers, wallpaper,
screensaver, languages, fonts, etc... are loaded each time the win.ini is
initialized. If this file becomes corrupt or bad, Windows will either not
load, or have several errors as it loads. Users looking to view or edit the
system.ini file can use the sysedit or msconfig utilities.
Users who are running Windows NT 4.0, 2000, XP, or later operating systems
no longer have a win.ini. Instead of storing these settings in this file, they
are stored in the system registry.
SYSTEM.DAT, USER.DAT files are part of windows Registry and can be edited
using REGEDIT or REGDT32 utility. Registry files can't be read with standard
text editors. Further, USER.DAT file corresponds to HKEY_LOCAL_USER and
SYSTEM.DAT corresponds to HKEY_LOCAL_MACHINE.
The following files are used by Windows NT/2000/XP Operating Systems.
It is a program loaded from the hard drive when the system starts up. The
NTLDR launches Windows NT/2000 or other OS subsequently. NTLDR displays the
boot options by reading from BOOT.INI file.
This is a text file that contains OSs available on the computer. The
contents are fetched by NTLDR and displayed as OS options. An example is
multi(0)disk(0)rdisk(0)partition(2)\WINDOWS="Microsoft Windows XP"
C:\ = "Microsoft Windows"
The program detects the installed
hardware on the system.
This file is used to provide
access to SCSI boot partition. If the name of the path in Boot.ini uses SCSI
syntax, the Ntbootdd.sys must be in the root folder of the system partition.
Ntuser.dat is stored on the local computer at:
User, and contains the default user profile. When a new user is created, the
user is assigned default properties as defined in ntuser.dat. One way to
change the default user settings is to edit ntuser.dat using registry editor
For example, if you want to set the default language to some other language
instead of the English, you can edit this file to correspond to the new