A+ Essentials Cram Notes 220-801

Started by certforumz, February 26, 2014, 10:08:21 PM

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Vijayb

13. Miscellaneous

Cleaning of PC components – tools used:

Recommended cleaning procedures for various components are as below:

1. Computer Cabinet: Use Mild detergent
2. Dust inside the computer: Use Compressed air
3. Tape drive: Use tape drive cleaning catridge
4. Floppy drive: Use Floppy drive cleaning kit
5. CD ROM drive: Use CD-ROM drive cleaning kit
6. Mouse: Use cotton swab with Isopropyl Alcohol.

IsoPropyl Alcohol is recommended for cleaning PCAs such as motherboards. Mild detergent can be
used for cleaning the outside cabinet or the keyboard.

The following devices require periodic cleaning:

1. Floppy drives
2. Tape drives
3. Printers
4. Mouse

Tools - Screw driver types:

· A Flat blade screw driver has Minus slot
· A Philips screw driver has X shape slot
· A Torx screw driver has star tip or head
· A Hex screw driver has hex head

ESD:

- It is important to know that ESD damage may not be known immediately. A component may only
suffer degradation in performance, which may show up only at a later date. In some cases, an ESD
may result in the failure of the component instantly.
- When working on computers, use special ESD wrist strap. Do not directly ground yourself with a
piece of wire. An ESD wrist strap has built-in resistor to prevent electric shock. Use specially designed grounded ESD mats. Do not wear synthetic clothing. Place all electronic components into anti static bags. Anti static bags can be reused. Keep your workplace clean.
- As the humidity decreases, static build up will increase. A level of 50% is considered safe. Below
50% humidity, static build up will be more.
- Electrostatic discharge (ESD) can damage the component at as little as 110 volts. CMOS chips are
most susceptible to ESD.

Terminate and Stay Resident programs, as the name suggest, stay inactive in the memory area of the computer. An example of a TSR is Screen saver program. To view, which programs are consuming how much memory area, MEM command can be issued with switch "C".

If you notice that the time is constantly incorrect, even after adjusting correctly, the most likely cause is that the CMOS battery has become weak and need to be replaced. Batteries, and chemical solvents contain environmentally hazardous chemicals and therefore, should not be disposed through dustbin. Always refer to the manufacturer's instructions or the relevant State
guidelines.

Vijayb

Power On Self Test (POST) happens after the computer cold boots.

A computer may reboot because the CPU is overheating. Ensure that you have sufficient ventilation
for proper airflow, and that the CPU fan is working.

The Hibernate option in Windows computer saves an image of your desktop, including all open
windows and files. Then it powers down your computer just as if you had turned it off. When you turn your computer on again, your windows and files are open just as you left them. You can enable hibernate on a Windows computer by right clicking on the Desktop, the then selecting Properties.

The automatic restart option in Windows XP is enabled by default. As a result, if there is any major
error, the Operating System will automatically restart. This can be disabled using System applet in the Control Panel.

Running a command like "ping" or "ipconfig" using Start -> Run, will open the command screen.
However, the command screen closes soon after the execution of the command. If you intend to
observe the results of any such command, you need to open the DOS screen by going to Program Files | Accessories | Command Prompt

It is recommended to close any open slots on a computer cabinet (case) to ensure proper airflow inside the case.

The file ntbtlog.txt file contains information collected if you choose to boot using "Boot Logging"
startup option. The file shows which drivers are loaded and which have failed to load.

Riser card typically holds multiple IO cards.

When you observe any hardware damage with a PC, first turn-off and unplug the unit. Then the
appropriate action would be to refer to the manufacturer's documentation or website for warranty or maintenance information.

Vijayb

#47
14. Others

1. IDE hard disks:

- An IDE hard disk can have one Primary partition and one Extended partition. An Extended
partition can be divided into one or more logical partitions. After partitioning the hard disk,
each partition needs to be formatted.
- The File System Boot Sector is the first physical sector on any logical volume.
- The first physical sector on any bootable hard disk contains Master Boot Record, MBR.
- The command FDISK will destroy all the data on a partition or drive on to which it is run.
- The primary partition can be made bootable, by marking partition as active.

2. FAT:

- Windows 98 and Windows 95 OEM Release 2 support FAT32. Note that Windows NT does
not support FAT32. NT supports only FAT16 and NTFS. Windows 2000 supports FAT16,
FAT32, and NTFS.
- DOS standard FAT16 support drives up to 2 GB. FAT32 supports drives up to 2TB
(Terabytes).

3. PC Utilities: The following DOS utilities are useful in proper maintenance of PCs.

A. SCANDISK: ScanDisk is a utility program that was added to DOS Version 6.0. SCANDISK
is a better compared to CHKDSK. SCANDISK can fix errors on data storage devices such as
hard disks, floppy disks, RAM drives etc, and DoubleSpace compressed drives. It analyzes and
repairs damage to the following:

    1. Physical clusters
    2. File allocation table (FAT)
    3. Lost clusters
    4. Cross-linked files
    5. Directory tree
    6. MS-DOS Boot sector
    7. DBLSPACE volume header, file structure, compression structure.

B. CHKDSK (Check Disk): CHKDSK command, one of DOS commands, examines your hard
drive for error conditions and reports the total size of the disk, how many files are stored there,
and the space remaining. CHKDSK also reports the total amount of conventional memory in
your system and the amount of conventional memory available. Note that CHKDSK can't report extended memory.

C. DFRAG: The DFRAG.EXE is included with DOS6.0 and later. DEFRAG utility arranges
the clusters of data on the hard drive to achieve better performance by placing all of the
clusters for a given file together in a contiguous order. DEFRAG does not do any repair on
your disk, and errors, if any will remain on the disk.

D. BACKUP: DOS has a backup utility since version 2.0.

Vijayb

4. .COM, .EXE, .BAT files are executable files.

5. DOS Boot up:

- IMPORTANT DOS FILES USED DURING BOOT UP ARE:

A. AUTOEXEC.BAT

- It does: Modifies the PC environment (PATH, SET, and other commands)
- Default Attributes: Nil
- Is it required for OS Start up: NO

B. CONFIG.SYS

1. It does: Loads low level device drivers and does performance tuning
2. Default Attributes: Nil
3. Is it required for OS Start up: NO

C. IO.SYS

1. It does: Loads basics Input/ Output routines for the processor
2. Default Attributes: Hidden / System/ Read Only 3. Is it required for OS Start up: YES

D. MSDOS.SYS

1. It does: Defines System File locations
2. Default Attributes: Hidden / System/ Read Only
3. Is it required for OS Start up: YES

E. COMMAND.COM

1. It does: The file contains internal command set and error messages
2. Default Attributes: Nil
3. Is it required for OS Start up: YES
4. Responsible for displaying the command prompt in a DOS based computer

F. HIMEM.SYS

1. HIMEM.SYS must be loaded before EMM386.EXE
2. HIMEM.SYS is used to address the extended memory

G. EMM386.EXE

1. 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).

H. ANSI.SYS

- The files AUTOEXEC.BAT, CONFIG.SYS, ANSI.SYS are not required for OS start-up.
However, the files IO.SYS, MSDOS.SYS, COMMAND.COM are required for OS start-up.
- To bypass the CONFIG.SYS, and AUTOEXEC.BAT files during boot process of DOS, you
need to press F5. F8 allows you to selectively bypass commands in AUTOEXEC.BAT, and
CONFIG.SYS.

Vijayb

6. DOS allows you to set the following attributes using ATTRB command:

  1. System
  2. Hidden
  3. Read-only
  4. Archive
   '+' sets and attribute
   '-' clears an attribute

Examples:

- The command ATTRIB +H myfile.txt will make the file myfile.txt hidden. The other attributes that
can be set using ATTRIB command are System, Read Only, and Archive.
- The command ATTRIB C:\private.txt +h +r will mark the file private.txt as both hidden and read
only.

7. DOS, Windows3.1 Windows 95/ 98 operating systems have the following characteristics:

    1. Each can have only one primary partition per hard disk
    2. The primary partition is automatically assigned a drive letter
    3. Each hard disk can have only one Extended partition
    4. You can create one or more logical drives in the Extended partition.
    5. The drive letters are assigned manually to logical drives.

Vijayb

8. The standard DOS partition cluster sizes are as given below:

16MB-127MB: 2KB cluster size
128MB-255MB: 4KB cluster size
256MB-511MB: 8KB cluster size
512MB-1023MB: 16KB cluster size
1024MB-2048MB: 32KB cluster size

Note that due to DOS limitation, the FAT on each hard drive partition can have 64K (65535)
individual addresses. Therefore, it is clear, depending on the size of partition, this number dictates the size of each cluster. We arrive at 32KB cluster size by dividing 2048(MB) with 64(KB).

9. The Windows 95/98 system files include the following:

A. IO.SYS
B. MSDOS.SYS
C. WIN.INI
D. COMMAND.COM
E. SYSTEM.INI
F. SYSTEM.DAT
G. USER.DAT

- MSDOS.SYS, WIN.INI, SYSTEM.INI are text files.
- 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.

10. HKEY_LOCAL_MACHINE is the hive where the information specific to the machine will be
stored. The information may include, network settings, hardware drivers etc.

HKEY_LOCAL_USER hive stores data specific to user configuration, such as desktop color schemes,
screen savers, wall paper, and user specific application settings.

11. Using FDISK, the following activities can be carried out:

    1. Create Partitions: You can create primary and extended partitions. Extended partition holds
one or more (Up to 23) logical drives.
    2. Set Active Partition: FDISK allows you to mark the primary partition as active partition.
    3. Delete Partition: You can delete a partition by using FDISK
    4. Display Partition Information.

Vijayb

12. DOS COMMANDS:

- MEMMAKER can be used to manage the system memory optimally. Windows 95 and above
automatically manage the memory, where as DOS requires manual memory management using
utilities like MEMMAKER. The DOS command MEM can only display the contents of memory, but
itself can't manage the memory.
- When you power on the DOS machine, you see a message, "Starting MS-DOS". If you press F5 key during this short period, you can bypass AUTOEXEC.BAT and CONFIG.SYS files.

Given below are common DOS commands that you use frequently:

    1. PATH: The command sets or displays a path for executable files. For example, "PATH=C:\;
       C:\DOS; C:\PROG; C:\MYFILES " command indicates DOS to first search ROOT, then
       C:\DOS, then C:\PROG, and finally C:\MYFILES for executable files.
    2. SET: Displays, sets, or removes DOS environment variable.
    3. PROMPT: Changes the DOS command prompt. The prompt can be made up of normal

characters and the following special codes:

$p Current drive and path
$l < ( less than sign)
$d Current date
$t Current time
$_ Carriage return
Syntax: PROMPT [text]

For example, to set the prompt to current date, followed by the current drive path, issue the
command:

PROMPT= $p$d

13. The file load order to start DOS is :

- IO.SYS
- MSDOS.SYS
- CONFIG.SYS
- COMMAND.COM
- AUTOEXEC.BAT
- Note that CONFIG.SYS, and AUTOEXEC.BAT are optional to load DOS. IO.SYS, MSDOS.SYS,COMMAND.COM are required.

Vijayb

14. When you format a disk with a "/s" switch (say "format a:/s"), the following files get transferred:

    1. IO.SYS
    2. MSDOS.SYS
    3. COMMAND.COM

- If you want to format a drive and also make it bootable, you need to format with /s switch.

15. Windows 95:

- The minimum published requirements for running Windows 95 is 386 processor with 4 MB of RAM.
Though it may be sufficient, the performance will be very poor and some applications may not run at
all. A recommended configuration is a Pentium processor with 32 MB of RAM.

- Booting Windows 95 in safe mode loads the drivers for Keyboard, Mouse, and standard VGA
graphics adapter.

- Windows 95 Version A supported only FAT16 file system. The maximum hard disk partition
supported by FAT16 is only 2 GB. However, Windows 95 Version B and Windows 98 support FAT32
and therefore, can support partitions upto 2TB (Tera bytes).

- SYSTEM.DAT and USER.DAT comprise of Windows 95 Registry. These are the files where most of
the user and system configuration information is stored. The Windows Registry files are stored in
\Windows directory by default.

- Windows 95 makes a backup of the Registry after every successful reboot. The Registry back up files are named: USER.DA0, SYSTEM.DA0. The original Registry files are named: USER.DAT,
SYSTEM.DAT. It may be noted, that in the event of boot failure, you can delete the original
USER.DAT AND SYSTEM.DAT files and the back up files can be renamed to DAT files and the
system can be rebooted successfully.

- While booting Windows 95, if you press F8, boot menu will be displayed. Windows 95 provides
three different modes that the system can be started.

    1. Normal Mode
    2. Safe Mode
    3. Command Prompt

- Normal Mode is the mode Windows 95 starts by default. It provides full functionality.
- Safe Mode is a diagnostic mode of Windows 95 that starts Windows 95 without any network, CD
ROM, and other drivers. The only device drivers loaded in Safe mode are:

    o Keyboard
    o VGA Display
   o Mouse Drivers

- Command Prompt mode is provided to run some old DOS applications that need to be run under
DOS only. These applications are primarily the ones which access hardware, that Windows 95 does
not allow to be accessed otherwise. Command Prompt mode is also useful for running FDISK and
MSD.

- The log file BOOTLOG.TXT records all the devices and drivers that the Operating System attempts
to load. BOOTLOG records the status of the devices and drivers.

- ScanDisk can be used to check disk drives for errors. The /f switch allows ScanDisk to automatically fix the errors.

- HKEY_CURRENT_CONFIG stores the hardware settings.

The six register keys available in Windows 95/98 Registry are:

A. HKEY_CLASSES_ROOT
B. HKEY_CURRENT_USER
C. HKEY_LOCAL_MACHINE
D. HKEY_USERS
E. HKEY_CURRENT_CONFIG
F. HKEY_DYN_DATA

- Adding $ sign to the end of the share name makes the share invisible over the network.

Vijayb

16. Some important TCP/IP port numbers are as given below:

    1. FTP: 21, stands for File Transfer Protocol
    2. Telnet: 23, stands for Telnetting from a remote terminal to a Telnet Server
    3. SMTP: 25, stands for Simple Mail Transfer Protocol
    4. HTTP/WWW: 80, stands for Hyper Text Transfer Protocol
    5. POP3: 110, stands for Post Office Protocol
    6. HTTPS: 443, stands for HTTP Secure

17. User level security gives better control of resource on user-to-user basis. Share level security
assigns passwords to the resources rather than the users and therefore less secure.

18. To pause the screen to view a large file, use |more switch. For example, to view autoexec.bat one screen at a time, type c:\autoexec.bat|more at the DOS prompt. Space bar can be used to go to next screen.

Vijayb

19. DNS stands for Domain Name System Server. DNS Server is the one responsible for converting
the Domain names to IP addresses.

20. TSR stands for Terminate and Stay Resident. An example of TSR program is a virus detection
program such as Norton Anti Virus.

21. If Autoexec.bat tried to access a drive letter that is not valid, the error message "Current drive is no longer valid" appears.

22. VIRUS:

    1. A boot sector virus stays resident by infecting the boot sector of the computer
    2. A Master boot record (MBR) virus infect the first physical sector of all affected disks
    3. File viruses either replace or attach themselves to executable files, and most commonly
          found virus.
    4. Macro virus attaches itself to documents in the form of macros.
    5. Memory viruses are viruses that execute and stay resident in memory. Trojan Horse is an
         example of memory virus.

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23. TCP/IP

- TCP/IP is the protocol used when you are Telnetting to a remote host. HTTP is used for accessing the World Wide Web services.
- SMTP is used to upload mail to the mail server. POP3 is used for downloading mail from a mail
server to a client machine running POP3 client.
- Both PPP and SLIP can be used for dial up connections. However, SLIP can't be used where the IP
address need to be assigned dynamically. The advantage of PPP is multi protocol support, that it can support TCP/IP, IPX, AppleTalk etc. SLIP can support only TCP/IP and IP addresses need to be
assigned manually.
- WINS server resolves the NetBIOS names to IP addresses. A Windows network running TCP/IP need to be configured with WINS (or LMHOSTS file on each computer) for NetBIOS name resolution.

24. Networking utilities:

      1. NBTSTAT: This utility displays current NetBIOS over TCP/IP connections, and display
           NetBIOS name cache.
      2. NETSTAT: Displays protocol statistics and current TCP/IP connections since the server was
           last booted.
      3. TRACERT: Used to determine which route a packet takes to reach its destination from
           source.
      4. IPCONFIG: Used to display Windows IP configuration information.
      5. NSLOOKUP: This utility enables users to interact with a DNS server and display resource
           records.
      6. ROUTE: Used to display and edit static routing tables.

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25. Some of the important commands useful in trouble shooting TCP/IP networks are:

     1. Ipconfig: Displays TCP/IP configuration values, including IP address, subnet mask, and
        default gateway.
     2. Ping: This command can be used to verify whether the target ip address or host name is
        present. You need to specify the target IP address or host name. You can ping the loop back
        address at 127.0.0.1. A response ensures that the TCP/IP stack is installed properly on your
        computer.
     3. Route: Displays and manipulates route information.
     4. Tracert: Determines the route packets take to reach the specified destination.

26. To see TCP/IP configuration on a Windows 95 / 98 computer, use WINIPCFG. It will display your
IP address, subnet mask, default gateway, hardware MAC address.

To see TCP/IP configuration on an NT machine, use IPCONFIG. It will also display the IP
configuration information on an NT machine. To get more details, use IPCONFIG/ALL.

27. DLL stands for Dynamic Link Library. DLL is a special form of application code loaded into
memory by request. A DLL is not executable by itself. More than one application may use the
functions offered by a DLL.

28. HTML stands for Hyper Text Markup Language. HTML is the language most widely used for
writing Web pages.

29. You can't apply file level permissions on a FAT file system. Only NTFS allows file permissions.
Remember that the NTFS file permissions are always in effect to all users and processes.

30. PAP and CHAP:

- PAP uses 2-way handshaking. Passwords are sent in clear text across the link. Therefore, PAP is to be used only when it not possible to use CHAP.
- CHAP uses 3-way handshaking. CHAP uses Challenge/ Response method, that provides protection
against the password capture while authenticating the user. One should use CHAP whenever it is
possible.

Vijayb

31. Windows 2000:

- Hardware requirements:

Hardware component                    Windows 2000 Prof.                             Windows 2000 Ser/ Ad Ser.

  Processor                                       Pentium/133MHz                                       Pentium/133MHz
  Memory                                              64MB                                                          256MB
  HD space                                           640MB                                                          1GB
  Display                                            VGA or better                                           VGA or better
  Network card                                   Optional                                                    Optional
  CD ROM Drive                                   Required                                                   Required
                                                                                                              (unless loading from network)
- When you install Windows 2000 in the same folder as that of Windows 95/ Windows 98/ Windows
NT, the operating system gets upgraded to Windows 2000.

- TCP/IP protocol stack is installed by default when you install Windows 2000 on a computer.

- You can use Regional Options to support additional languages on your computer. With the support of additional languages, you will be able to edit documents written in those languages. You can also set locale specific to any region using this Option.

- The Windows 2000 Performance tool is composed of two parts:

     1. System Monitor, and
     2. Performance Logs and Alerts.
- With System Monitor, you can collect and view real-time data about memory, disk, processor,
network, and other activity in chart (graph), histogram, or report form.

- Through Performance Logs and Alerts you can configure logs to record performance data and set
system alerts to notify you when a specified counter's value is above or below a defined threshold.

- Event Viewer maintains logs about program, security, and system events. You can use Event Viewer to view and manage the event logs, gather information about hardware and software problems, and monitor Windows 2000 security events.

To open Event Viewer, click 'Start', point to 'Settings', and then click 'Control Panel'. Double-click
'Administrative Tools', and then double-click Event Viewer.

- Encrypting File System (EFS) keeps your documents safe from intruders who might gain
unauthorized physical access to your sensitive stored data by stealing your laptop or Zip disk, or by
other means.

You need to ensure the following before the upgrade:

  1. The hardware is adequate for upgrading to Windows 2000 Professional
  2. Also, check the hardware, software adequacy by running "Winnt32.exe / checkupgradeonly". Note that the switch "checkupgradeonly" will output a report on the adequacy of hardware and software. It will also warn you if any applications need upgrade packs, which may be obtained from respective application vendors, if available. If the  software upgrade pack is not installed for any application, the application may be rendered unusable!

- If you are creating a Striped volume on a new Windows 2000 machine, it can only be created on
dynamic disks. However, if you are upgrading a Windows NT computer to Windows 2000, any
existing stripe set will be supported.

- For creating Stripe set with parity, we need at least 3 disk volumes.

- Placing the paging file on different physical disks is optimal. This will improve faster access to the
Paging file, and also distribute the load.

- Microsoft Internet Explorer and Windows Explorer can be used for assigning Share and NTFS
permissions on a Windows 2000 computer.

32. File names can be 255 characters long on a FAT, FAT32, and NTFS file systems.

Vijayb

33. Windows 2000 system monitoring:

Some of the important System Monitor counters are:

  1. Memory>Available Mbytes: measures the amount of physical memory that is available.
Typically > 4MB. If less than 4 MB, consider adding more memory.
  2. Memory>Pages/Sec: Shows the number of times that the disk has been accessed, because
requested information was not available in memory. If the value of the counter is not below 20,
you should add more memory. A value of 4 or 5 is typical.
  3. Paging File>%Usage: Indicates the % of allocated page file utilization. Should be less than
99%.
  4. Processor>%Processor Time: measure the time that the processor is busy. Should be
typically less than 80%
  5. Processor>Interrupts/Sec: Indicates the average number of hardware interrupts that the
processor receives each second. If more than 3,500, you can suspect a program or faulty
hardware.
  6. PhysicalDisk>%Disk Time: Measures the amount of time that the physical disk is busy
servicing read or write requests. If more than 90%, you can improve the performance by
adding another disk channel.
  7. PhysicalDisk>%Current Disk Queue Length: indicates the number of pending disk requests
that need to be processed. The value should be less than 2. The disk problems might arise from
less memory, resulting in usage of excessive paging. Ensure that the memory is sufficient
before attending to the disk problem.
8. LogicalDisk > %Free Space counter: Indicates the amount of logical disk's free disk space.
Typical value is 10% or above.

34. To insert a new file extension, you use Windows explorer, and select the application. Then, Tools
-> Folder Option -> File Types. Configure the extension appropriately

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35. Windows 2000 disk volumes:

Windows 2000 Operating systems support 5 different volume types:

    1. Simple volumes
    2. Spanned volumes
    3. Striped volumes
    4. Mirrored volumes
    5. RAID-5 volumes

A simple volume consists of a formatted disk on a single hard disk.

A Spanned volume consists of disk space on more than one hard disk.

A Striped volume has disk space on 2 or more disks. The disk spaces must be same on all disks.
Fastest disk access among all volume types. RAID level 0.

A mirrored volume consists of a Simple volume that is mirrored in total, onto a second dynamic disk.
Provides highest level of fault tolerance. Mirroring is RAID level 1

A RAID-5 volume consists of identical sized disk space located on three or more dynamic disks. Here
any single disk failures can be recovered.

Note that Windows 2000 Professional doesn't support Mirrored and RAID-5 volumes, where as other Windows 2000 Operating Systems (2000 Server, Advanced Server) support.

36. Fault tolerance boot disk is a floppy disk that enables you to boot a computer in the event that the first disk in a mirrored volume fails. If you mirror the installation folder in a Windows 2000 Server, you will not be able to boot because boot.ini points to the first volume. Therefore, you need to create a fault tolerance boot disk that contain an appropriately edited Boot.ini file, that points to the mirrored volume.

37. By default, you can start recovery console (in Windows 2000) using,

  1. The Windows 2000 Professional Setup Disks

  2. From the CD ROM drive using Windows 2000 Professional CD (if the CD –ROM drive is bootable).

Also, you can have "Recovery Console" as a start up option by typing \i386\winnt32.exe /cmdcons at the command prompt, after switching to the CD ROM drive letter.