Unit – IV - Installation and Preventive Maintenance
Introduction – system configuration – pre installation planning – Installation practice – routine
checks – PC Assembling and integration – BIOS setup – Engineering versions and compatibility
– preventive maintenance – DOS – Virus – Data Recovery
1. List the applications for special system configuration.

DTP

CAD, CAM

Supermarket

Games

Image Processing

Voice Reorganization

Process control

Network Server

Bank

Data Center
2. List the hardware items for common applications.

Scanner, Laser Printers

Plotter

High Resolution display

Joy stick

CD-ROM, DVD-ROM

Digital Camera

Microphone

Bar code Reader
3. What are the aspects that the user should consider while buying a computer product?
 Hardware and modules used
 Manufacturing quality/reliability
 Ease of maintainability and product engineering
 Upgradeability provision
 Warranty duration
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Probability of failure
4. Draw the Bath Tub Curve for Product life time.
Infant
Mortality
(25 Weeks)
Product Life
(25 Years)
Wear & Tear
Period
5. What are the factors to be considered while choosing hardware modules?

Performance level required: low, medium, high

Type of usage: light, medium, heavy

Nature of application: personal, commercial, govt service

Criticality of system application: low, high

Location of site: rural, urban

Product engineering: industry standard, non-standard
6. List the different levels of hardware configuration.
S.No
1
2
3
4
5
6
7
8
Hardware Item
Processor Type
Processor Clock
RAM Capacity
HDD Type
HDD Capacity
Monitor Size
Power Supply
CD-ROM drive
Entry Level
Celeron
900 MHz
128 MB
IDE
20 GB
14 Inch
250 Watts
48X
Mid Level
Pentium III
1.2 GHz
128 MB
IDE
40 GB
15 Inch
250 Watts
52X
High Level
Pentium 4 in FRC
2.4 GHz
3 GB
SCSI
40 GB
17 Inch
300 Watts
52X
7. What is the advantage of using AC stabilizer?
All PCs have SMPS with built-in ac input stabilizer. However, if the ac input supply is
too bad to be managed by the PC, an external AC stabilizer is essential. The use of a
stabilizer is essential if you have a hard disk in the system. If a UPS is installed, the built-in
stabilizer in the UPS handles the voltage fluctuations.
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8. What are the requirements are need in pre-installation planning?

Placement / Site Selection

Air Conditioning

AC Power Interference

AC Stabilizer

Power Supply Capacity
9. Do we need to air condition the room wherein the PC is kept?
The necessary of air condition depends on the environment. The PC has a built-in cooling
arrangement which is sufficient in general. But if the user operating the PC in a very hot
environment, user should provide for external cooling of the room. A simple window air
conditioner is sufficient.
10. List some of the PC SMPS ratings.
PC Model
SMPS Wattage
PC-8088
63.5 W
PC/XT
130 W
AT-286
192 W
Celeron PC
200 W
Pentium III PC
250 W
Pentium IV PC
300 W
11. What are the abnormal aspects / defects in the PC after unpacking?
After unpacking the PC, carry out a through visual check to detect any of the following
abnormal aspects / defects:

Loose connection

Incorrect setting of DIP switches

Broken wire or cables

Loose Screws

Missing Screws

Wrong Connection

Missing Jumpers

Physical Damage to cabinet or peripherals
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12. Why hard disk drive is shipped by the manufacturer with a ‘tie-down’?
The hard disk drive is shipped by the manufacturer with a ‘tie-down’ pin or clip on the
positioning mechanism to prevent movement of the heads during transport.
13. Write short notes on Pre-shipment burn.
In order to minimize the chances of problems with a new PC soon after you get it home, it's a
good idea to have the PC tested before shipment. This is sometimes called a "burn-in" test,
and is done to pre-screen systems to weed out bad components. Since most component
failures occur very quickly, running tests on a system for 24 hours or so can eliminate some
common faults. Obviously, it is to everyone's advantage if a problem is discovered before the
PC is delivered to the customer rather than afterwards.
14. What are essential steps to remove a motherboard?

Switch off the system, monitor and printer

Remove all daughterboard’s

Remove the keyboard connector from the rear side of the system box

Remove the SMPS power connectors from the system board

Remove the front h panel connector

Remove all I/O Connectors

Remove FDDs and HDDs

Remove screws and the rubber washers on the motherboard

Lift the motherboard gently and take it out of the system box
15. What are the routine checks should follow by the engineer?

FDD Jumper: Drive Select

FDD Cable: Twist

FDD Terminator

Memory Jumpers

Cable Connectors Orientation

Processor Heat sink / Cooling Fan
16. What are the advantages in assembling a PC?
 Saving money
 Choosing exact configuration
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 Gaining expertise which will be useful when the system fails
 Ease of future up gradation
17. What are the steps involved in motherboard stuffing?
 Installing socket processor: The Pentium 4 motherboard uses a processor socket such as
socket 423. Pull the locking lever away from the socket, then raise the lever to a 90degree angle. Place the processor gently into the socket matching the pin no. 1 on the
socket and the processor chip without applying force.
 Installing the processor cooling fan: The Pentium 4 comes with a specific fan. Open the
levers of the retention mechanism. Place the fan into the retention mechanism. Close the
levers.
 Installing Slot-1 processor: The slot-1 in the motherboard has a cartridge holder. While
shipping the motherboard, the upright struts are put in folded down position. Pull them up
and make them in upright position. Insert the processor cartridge into the cartridge holder.
 Memory modules: hold the DIMM above the DIMM socket and align the two modules
in the bottom edges of the DIMM with the two keys in the socket. Insert the bottom edge
of the memory module into the socket.
18. List the PC Assembling sequence.

System box preparation

Motherboard stuffing

Motherboard Installation

IDE Drives Preparation

Drive Installation

Daughterboard’s Installation

Cables Connection

Power Connections

BIOS Setup

Loading Software: Operating System and Special I/O Drivers
19. What are the softwares items needed to assemble a PC?

Operating system (to be purchased separately)

Motherboard drivers (Come on a CD with motherboard)

Device Drivers (Come with devices)
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20. What are the basic tools need to assemble a PC?

Philips Screwdriver

Flat Screwdriver

Pliers (need nose)

Marker Pen
21. Write short notes on Motherboard installation.
Mount the motherboard into the cabinet using the original screws with a Phillips headed
screwdriver. Gently place the board inside the cabinet adjusting such that the mounting holes
on the motherboard are in alignment with the holes on the cabinet. Fix the motherboard by
screwing in the mounting screws.
22. What are a BIOS setup and a standard CMOS setup?
 The BIOS has a setup utility program for specifying the system configurations and
settings. When u switch on the system, the BIOS gets control and it starts POST.
 “Standard CMOS setup” option enables you to enter some basic hardware configurations
and set the system clock and error handling.
23. What are the hard disk drive specifications? Or Define Type User.
If the hard disk drive is a special one, user can use “Type User” to define the drive
specifications manually. If user selects Type User, relevant data has been entered for the
following items:
CYLS
number of cylinders
HEAD
number of read/write heads
PRECOMP
write precompensation cylinder
LANDZ
landing zone cylinder
SECTOR
number of sectors
SIZE
capacity (displayed according to the configuration)
MODE
access mode: Auto
Normal (HD<528 MB)
Large (for MS-DOS only)
LBA (HD>528 MB and supports logical block addressing)
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24. What is a swap floppy drive?
This item allows you to enable to Swap floppy drive or not. When enabled, the BIOS swaps
floppy drive assignments so that drive A becomes drive B, and drive B becomes drive A.
25. Write the date format in Standard CMOS setup.
The date format is:
Day: Sun to sat (Display only; calculated by BIOS)
Month: 1 to 12
Data: 01 to 31
Tear: 1901 to 2099 (set by user)
26. Write the time format in Standard CMOS setup.
Time: to set the time, highlight the “Time” field and use the <PgUp> / PgDn> or + / keys to set the current time.
The Time format is:
Hour: 00 to 23
Minute: 00 to 59
Second: 00 to 59
27. List the Hard disk drive access modes.
The Hard disk access modes are:

Auto mode

Normal mode (HD < 528 MB)

Large mode (for MS-DOS only)

LBA ( HD>528MB & Supports Logical Block Addressing)
28. What are the types of Video display adapter?

CGA

MDA

EGA

VGA

SEGA

SVGA

PGA
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29. List some of features in Advanced BIOS setup.

Virus warning

CPU internal Cache

External Cache

Boot sequence

Swap floppy drive

Boot Up Floppy Drive
30. What is virus warning in BIOS Setup?
The virus warning feature protects the boot sector and partition table of the hard disk
against overwriting. If any write attempt is made, the BIOS halt the system and displays a
warning message so that user can either allow the operation to continue or run an anti-virus
program to locate and remove the virus.
31. What is a boot up floppy seek?
When enabled, the BIOS will give a seek command to floppy drive A before booting the
system. It can find out whether the floppy drive installed has 40 or 80 tracks. The 360K FDD
has 40 tracks where as 760K, 1.2M and 1.44M FDD’s have 80 tracks.
32. What is a boot up numlock status?
This allows you to enable or disable the numlock function during boot up as per your
personal taste. If set to ‘on’, it turns on numlock key when the system is powered on. If set to
‘off’, it turns off the numlock key so that you can see the arrows on both the numeric keypad
and the main keyboard.
33. What do you meant by Gate A20 option?
This option is related to ‘High Memory Area’ (HMA). It controls the use of A20 address
bit. The A20 gate signal is generated by the keyboard controller logic (8042/8742) and RAM
access above 1MB is handled through it.
34. What is a PCI/VGA palette snoop?
Some non standard VGA display adapters may not show colours properly. This field
allows you to set whether MPEG ISA/VESA VGA cards can work with PCI/VGA or not.
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When this field is enabled, a PCA/VGA can work with a MPEG ISA/VESA VGA card.
When disabled, a PCI/VGA cannot work with a MPEG ISA/VESA card.
35. Define Typematic Rate & Typematic Delay.

Typematic Rate: The speed of repetition ranging from 6 to 30 characters per second.

Typematic Delay: Initial tine interval before starting the repetition. Typically 500
msec.
36. What is video BIOS shadow?
The video BIOS Shadow allows changing the video BIOS area from ROM to RAM after
copying. Video BIOS shadowing increases the video speed: But may cause problems while
running some operating systems or applications.
37. List some of the advanced chipset features setup?
 DRAM cycle time selection: this field sets the DRAM cycle time. The common options
are 6ns and 70ns.
 MA wait state: this field fixes the wait state of the memory address. The settings are fast
and slow.
 CPU to PCI IDE posting: when enabled, the CPU to PCI IDE posting cycles are treated
as normal I/O write transactions.
 System BIOS cache: when enabled, access to the system BIOS ROM addressed at F0000
– FFFFF are cached to RAM for faster execution.
38. What is meant by 8 bit I/O recovery time?
This option specifies the length of the delay in sysclks inserted between consecutive 8-bit
I/O operations. The settings are 1,2,3,4,5,6,7 or 8.
39. What is meant by16 bit I/O recovery time?
This option specifies the length of the delay in sysclks inserted between consecutive 16bit I/O operations. The settings are 1,2,3,4,5,6,7 or 8.
40. What is the usage of passive release?
When enabled, CPU to PCI bus access are allowed during passive release. Otherwise the
arbiter only accepts another PCI MASTER access to local DRAM.
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41. What is a delayed transaction?
The chipset has an embedded 32 bit posted write buffer to support delay transactions
cycles. Select enabled to support compliance with PCI specification version 2.1.
42. What is an AGP aperture size?
The field sets aperture size of the graphics. The aperture is a portion of PCI memory
address range dedicated for graphics memory address space. Host cycles that hit the aperture
range are forwarded to the AGP without any transaction. The options available are 4MB, 8M,
16M, 32M, 64M, 128M and 256M.
43. What is SDRAM RAS-to-CAS delay?
This field is used to insert a timing delay between the CAS and RAS strobe signals, used
when DRAM is written to, read from, or refreshed. Fast gives faster performance, and slow
gives more stable performance.
44. What is SDRAM RAS pre-charge time?
If an insufficient number of cycles are allowed for the RAS to accumulate its charge
before DRAM refresh, the refresh may be incomplete and the DRAM may fail to retain data.
Fast gives faster performance, and slow gives more stable performance.
45. What is CAS latency time?
When synchronous DRAM is installed, the number of clock cycles of CAS latency
depends on the DRAM timing. Do not change this field from the default value specified by
the system designer.
46. What are the four selections for power management?
 Disabled: No power management
 Min.Power Saving: Minimum power management
 Max.Power Saving: Maximum power management. Only available - for SL CPU.
 User Define: Each of the ranges are from 1 min. To 1 hr.: Except for HDD Power Down
which ranges from 1 min. To 15 min. (default)
47. What is Video Off method?
This field defines the video off features. There are three options.
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 V\H SYNC+ Blank: blank the screen and turn off vertical and horizontal scanning.
 DPMS: Allows the BIOS to control the video display card if it supports the DPMS
features.
 Blank Screen: This option only writes blanks to the video buffer.
48. What is video off after?
As the system moves from lesser to greater saving modes, select the mode in which you
want the monitor to blank.
49. How is the modem use IRQ?
This field names interrupt request (IRQ) line assigned to the modem (if any) on your
system. Activity of the selected IRQ always awakens the system.
50. What is Doze Mode?
When enabled, and after the specified time of system inactivity, the CPU clock will run at
a slower speed while all other devices still operate at full speed.
51. What is Standby mode?
After the specified period of system inactivity, the hard disk drive and the video shut off
all other devices still operate at full speed.
52. What is suspend mode?
When enabled, and after the specified time of the system inactivity, all the devices except
the CPU will be shut off.
53. What is HDD Power Down?
When enabled, and after the specified time of system inactivity, the hard disk will be
powered down while all other devices remain active.
54. What is throttle Duty cycle?
When the system enters Doze mode, the CPU clock runs only part of the time. You may
select the percent of time that the clock runs. It is called as throttle Duty Cycle.
55. What is IRQ 8 break suspend?
Either by using enable or disable monitoring of IRQ8 (the Real Time Clock), it does not
awaken the system from Suspend Mode.
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56. What are integrated peripherals?
The integrated peripherals option in CMOS setup sets the hard disk configuration, mode &
port. Some of the utilities in this section are:

IDE HDD Block mode

IDE Primary Master PIO

IDE Primary Slave PIO

IDE Secondary master PIO

IDE Secondary Slave PIO
57. What is soft off by PWR BTTN?
This field defines the power off mode when using an ATX power supply. The instant off
mode allows powering off immediately upon pressing the power button. In the Delay 4 Sec
mode, the system powers off when the power button is pressed for more than four seconds or
places the system in a very low usage state with only enough circuitry receiving power to
detect power button activity or Resume by Ring activity when pressed for less than 4
seconds.
58. What is onboard FDC controller?
Select enabled to use the floppy disk controller (FDC) on the system board. If you install
a FDC option daughterboard or if the system has no floppy drive, select disabled in this field.
This option allows selection of the onboard FDD port.
59. What is the usage of onboard serial/parallel port?
These fields allow you to select the onboard serial and parallel ports and their address.
The default values for these ports are
Serial port 1
3F8/IRQ4
Serial port 2
2F8/IRQ3
Parallel port
378/IRQ7
60. What are the functions of parallel port mode?
This field determines parallel port mode function
SPP
Standard (Centronics) printer port
EPP
Enhanced parallel port
ECP
extended capabilities port
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61. Define Supervisor / User Password.
Supervisor Password: The supervisor password sets a password that will be used to protect
the system and setup utility.
User Password: User password sets a password that will be used exclusively on the system.
62. Write short notes on Preventive maintenance.
Preventive maintenance steps are prescribed by the manufacturer should be done periodically
using appropriate materials in PC. One of the essential PM procedures is cleaning dust prone
parts. This has to be done carefully by trained personnel.
63. What are general problem sources on PC?
The general problem sources are:

Dust

High Temperature

Electrical noise / Interference

Magnetic fields

Corrosion

Power fluctuations
64. List some general precautions for PC maintenance.

Switch off the monitor, system unit and printer before switching off the system

Before removing a board or peripheral, remove all the cables, connectors and screws
connected to it.

Power off the PC and the peripherals before doing any of the following activities:

Remove or inserting a PCB

Removing or plugging a cable

Connecting or disconnecting any peripherals
65. What are the two basic things that an OS does?
 Manage the hardware resources of the computer for efficient utilization
 Provides user interface, i.e., receives commands from the user, acts on them, and gives
out error messages.
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66. List the types of operating system.
Operating system can be classified as follows:
Single user system:
The single user system runs one user program at a time, supports only one user at a time.
Example: MS-DOS
Multi user system:
The multi user system permits several user programs to be executed concurrently. A multi
user operating system takes care of switching CPU among the various programs
Example: UNIX, Window 98, etc.,
67. How class the nucleus of MS-DOS is made of?
IO.SYS
MSDOS.SYS
COMMAND.COM
In PC DOS, the first two files are called as IBMBIO.COM and IBMDOS.COM respectively.
68. Explain IO.SYS file.
This file contains extensions to the ROM BIOS. These extensions include correction to
the existing ROM BIOS routines and new routines for newer peripheral devices. ROM BIOS
routines and IO.SYS routines are the lowest level systems software available, that performs
the most fundamental and basic I/O operations.
69. Explain MSDOS.SYS.
This file contains I/O routines that do higher level I/O operations. These routines are
more sophisticated and thus occupy the next level up. They provide the user programs more
comfortable and simple handling of I/O operations than the ROM BIOS routines. Programs
normally call these routines which in turn may call routines in the IO.SYS file and the ROM
BIOS.
70. Explain DOS internal commands.
A command is usually a request to execute a program. Our programs are mostly stored on
disks as distinct disk files. However, not all command programs are kept in separate disk
files. Some of the most important and frequently used command programs are inside
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COMMAND.COM itself. These are called INTERNAL COMMANDS. To carry out these
commands, it is not necessary to read a program file from disk.
71. Define Command.com.
Command.com is a program with which the user interacts. It provides user interface, and
is called the command processor. It contains routines that interrupt the command typed in the
command mode. It accepts and acts on commands given by the user. Commands are nothing
but requests for execution of a program.
72. Explain DOS external commands.
These are programs that are stored on disks as separate disk files. They are of 3 types
 EXE files
 COM files
 BAT files
While COM and EXE files are programs, a batch file is a text file that contains a number of
conventional program commands. By entering a single command (the batch file’s name),
DOS’s command processor is asked to carry out all the commands inside the batch file.
73. Give the name of some internal commands in DOS.

CLS: To clear the screen

DIR: List the files in directory

DEL: To delete the files

COPY: To copy the file contents from source to target.

DATE: To Display the system date

Type filename: To display the file contents
74. Give the name of some external commands in DOS.

Format Drive: To format a specified drive

FDISK: Configure the hard disk for use

LABEL: Assigns a new volume label to disk

DISKCOPY: Copies the contents of the floppy disk

Backup: Back up one or more files from one disk or another

Restore: Restore one or more backup files from a disk to another disk
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75. Describe special files in DOS.
The special files contain special configuration commands that are used to configure the
system. Each time when the DOS starts up, it searches the root directory of the drive it was
started from, for the file named CONFIG.SYS (The Configuration file).
76. What are the commands used in AUTOEXEC.BAT?
The following are the two commands that will be useful if included in the
AUTOEXEC.BAT file:

path[(d:)path(;(d:)path)..): Allows user to instruct DOS to search in the specified
directories, when it does not find the command user have entered, in the current directory.

prompt(prompt-text): Allows user to set a new DOS prompt. User can make the DOS
prompt include the time, the date the current directory of the default drive, etc.
77. Explain files area in DOS?
The files area occupies the greater portion of the disk space, and is used to store files, and
sub-directories. The files area is divided into smaller units called clusters. A cluster is one or
more consecutive sectors, and the number of sectors in a cluster depends on the disk format.
DOS allocates clusters to a file, one cluster at a time, as and when needed. When a file needs
more space, DOS allocates one or more cluster to it.
78. Draw the Logical organization of Disk.
Boot Record
FAT
Root Dir.
Data Area
System Area
79. Explain system area in DOS.
The system area is divided into three separate areas, namely the boot record, the FAT File
Allocation Table, and the root directory. The size of each area varies among different
formats, but the order of these areas does not change.
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80. Explain boot record in DOS.
The boot record is the very first sector on the disk. It contains a small program that begins
the process of loading DOS from the disk into the computer’s memory. This program finds
out if the disk is system-formatted by looking for the two DOS system files names in the first
two entries in the root directory. If it does not find them, it gives a error message: Nonsystem diskette.
81. Explain FAT in DOS.
The File Allocation Table gives an account of how the disk space in the files area is used.
Space used for files, space that is not in use, and space that cannot be used due to defects.
DOS maintains two identical copies of FAT.
It is organized as follows. It has an entry for every cluster in the files area. The first two
entries contain a media descriptor value which indicates the format of the disk. The
remaining entries are used to link together the different parts of life. The FAT entry for the
each cluster in a file holds the number of the next cluster.
82. What is a root directory?
The root directory is the next item and is used as a table of contents. Each file on the disk
has a 32 byte entry in it, which contains the name of the file, file name extension, size of the
file, the time and date it was last modified and the starting cluster number. For a given disk
format, the size of the root directory is fixed, and consequently the number of files that could
be placed in the root directory is fixed.
83. Draw the FAT organization.
DIR
NOTES
FAT
TXT
0003
0005
3
0007
4
5
17
EOF
6
7
84. What are the parts of a directory and how much size does each part occupy?
Filename
8 bytes
Filename extension
3 bytes
Attribute
1 byte
Reserved (zeroes)
10 bytes
Time
2 bytes
Date
2 bytes
Starting cluster no
2 bytes
File size
4 bytes
85. Define Load BIOS Defaults & Load Setup Defaults.
Load BIOS Defaults: This option allows user to load the troubleshooting default values
stored in the BIOS ROM. These default settings may not be optimal and disable all high
performance features.
Load setup defaults: This option allow user to load the default values to their system
configuration. These default settings are optimal and enable high performance features.
86. What are the commands used to recover the files?
The commands used to recover the files are:

Undelete

Un-format
87. Explain DOS versions.
MS DOS 3.2 is most suitable for small PCs with 640 KB RAM. This is because of the
small amount of RAM the operating system occupies thereby facilitating more RAM for
application programs.
MS DOS 4.0 incorporates support beyond 32 MB HDD which
previously was DOS limitation requiring third party software like disk manager for
partitioning into smaller logical disks.
88. What is a virus?
A computer virus is a software program which has the ability to attach itself or infect
other programs as well as replicate itself without the PC user’s knowledge.
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89. What is data recovery?
Data recovery is the process of salvaging data from damaged, failed, corrupted, or
inaccessible secondary storage media when it cannot be accessed normally. Often the data are
being salvaged from storage media such as hard disk drives, storage tapes, CDs, DVDs,
RAID, and other electronics. Recovery may be required due to physical damage to the
storage device or logical damage to the file system that prevents it from being mounted by the
host operating system.
90. List some of the virus actions?
 Most viruses tend to fill up the hard disk with useless data. A virus reproduces, and every
copy of the virus takes up valuable space .
 Scramble the File Allocation Table. Any overwrite to the FAT will cause data to be
irrecoverable lost.
 Wipe out the boot sector or partition table which contain system information. If these
areas are altered, your computer may not function or the infected disk may become
unusable.
 Change data in programs or files and cause erratic results.
91. What are the types of viruses?
There are two types of viruses
 Boot virus: Boot block viruses are those that infect the partition sector or the boot sector
of diskettes. Such viruses gain entry into the system only when booted from an infected
disk. On booting from an infected disk, these viruses get activated and infect the hard disk
by writing its code on the boot sector or partition table.
 File virus: file viruses infect executable files such as .COM, .EXE or overlays such as
.SYS, BIN, .OVR, etc. They infect the files by appending their own code to the
executable files and become active, whenever an attempt is made to execute the file. Due
to this, the infected file grows in size and the date and time will be modified.
92. What is vaccine?
A vaccine is a unique software solution that helps you in the war against the dreaded
computer viruses, present and future. Several products are available in the market. A trial
version copy of VX2000 plus, a popular antivirus tool is included in the CD which may be
upgraded from the developer.
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93. What a vaccine does?
 Detection: Some vaccine provide a utility that is memory resident. This will indicate the
presence of a virus on the disk being used. Such a utility mostly does not occupy much
space in the RAM.
 Removal: Vaccines provide the facility to kill the viruses that are detected.
 Immunization: Some vaccines provide immunization for floppy diskettes from further
viral attacks. Immunization is possible in some cases only.
94. What are the third party data recovery tools?
There are several data recovery tools available from third party software companies.
EX:

Norton utilities

PC tools

Mace utilities

Some of the features provided by these tools are now also incorporated into DOS.
95. Explain the two important tools in Norton utility.
 Disk tool: This is a utility developed by Peter Norton Computing Inc. This is an easy to
use menu driven software. To run it, type disk tool at the DOS prompt.
 Norton Disk Doctor: To run it type NDD at the DOS prompt.
96. Draw the block diagram of DOS memory map
00000
Interrupt vector table
Dos & BIOS data area
IO.SYS
MS DOS SYS
Device drivers
Initialization portion of
COMMAND.COM
User program area
9FFFF
Transient portion of
COMMAND.COM
20
640k
97. What are the steps to be taken on finding a virus?

Switch off the computer system to ensure that the virus in the memory does not spread
any more.

Confirm if the problem is actually because of the virus. It could be hardware or other
software related problem.

Boot from a clean write-protected floppy diskette.

Check your system for extent of infection and repair or delete all the infected files.
98. What are the precautions to be taken against virus?

Switch off the preview feature in your email browser

Do not open attachments if you are not expecting them

Get and use an anti virus scan program

Backup critical data on a regular basis

Avoid Bootleg or Pirated Software

Treat Floppy Disks and CDs With Suspicion

Check System Requirements.

Scan All Drives.

Update Often.
99. List the Advantages of DOS5.0.
In early DOS versions had insufficient memory area. DOS5.0 can make use of the following
memory areas.
100.

High memory area(HMA)

Extended memory

Emulated expanded memory

Upper memory Blocks(UMBs)
List the floppy disk format in physical dimensions.
Physical Dimensions
Physical size
Slides
Track Density
Tracks per Side
Sectors / Track
Total Sectors
360KB (DSDD)
5.25”
2
48
40
9
720
1.2MB (DSHD)
5.25”
2
96
80
15
2400
21
720K (DSDD)
3.5”
2
135
80
9
1440
1.44MB (DSHD)
3.5”
2
135
80
18
2880
101.
List the floppy disk format in logical dimensions.
LogicalDimensions
Overhead Sectors
 Boot Program
 FAT
 DIR
 Total
Actual Data Space
Sectors / Cluster
Total no. of Cluster in
Space
Cluster no. Range
Dir Entries
102.
360KB (DSDD)
1.2MB (DSHD)
720K (DSDD)
1.44MB (DSHD)
1
4
7
12
708
2
354
1
14
14
29
2371
1
2371
1
6
7
14
1426
2
713
1
18
14
33
2847
1
2847
2-355
112
2-2372
224
2-714
112
2-2848
224
What is the use of HMA?
The high memory area (HMA) is the RAM area consisting of the first 64 kibibytes
(KiB), minus 16 bytes, of the extended memory on an IBM PC or compatible
microcomputer.
103.
What is UMBs?
Upper memory area (UMA) refers to memory between the addresses of 640 KB and
1024 KB (0xA0000–)0xFFFFF) in an IBM PC or compatible. IBM reserved the
uppermost 384 KB of the 8088 CPU's 1024 KB address space for ROM, RAM on
peripherals, and memory-mapped input/output. For example, the monochrome video
memory area runs from 704 to 736 KB (0xB0000–B7FFF).
However, even with video RAM, the ROM BIOS and I/O ports for expansion cards,
much of this 384 KB of address space was unused. As the 640 KB memory restriction
became ever more of an obstacle, techniques were found to fill the empty areas with
RAM. These areas were referred to as upper memory blocks (UMBs).
104.
What is UMA?
Upper memory area (UMA) refers to memory between the addresses of 640 KB and
1024 KB (0xA0000–)0xFFFFF) in an IBM PC or compatible. IBM reserved the
uppermost 384 KB of the 8088 CPU's 1024 KB address space for ROM, RAM on
peripherals, and memory-mapped input/output. For example, the monochrome video
memory area runs from 704 to 736 KB (0xB0000–B7FFF).
22
105.
Draw the diagram for extended memory in DOS.
00000
640K
Conventional RAM
9FFFF
FE000
FFFFFF
100000
BIOS ROM
HMA
10FFFFF
Extended Memory
106.
Define sub directory.
A sub directory also is a table, with entries similar to the root directory. As the
disk could hold a large number of files belonging to different users, it is wise not to
represent all the files in the Root directory. Instead group of files can be representing in
different sub-directories.
`
23
Pre-installation Planning
Answer Key
 Placement / Site Selection
 Air Conditioning
 AC Power Interference
 AC Stabilizer
 Power Supply Capacity
 Typical PC SMPS Ratings
Installation practice
Answer Key
 Unpacking and Checking
 Removing a Motherboard
 Removing and Replacing Daughterboard
 Removing FDD
 Mounting FDD
Routine Checks
Answer Key
 FDD Jumper: Drive Select
 FDD Cable: Twist
 FDD Terminator
 Memory Jumpers
 Cable Connectors Orientation
 Processor Heat sink / Cooling Fan
PC Assembling & Integration
Answer Key
 Advantages of Assembling

Saving Money

Choosing Exact Configuration

Gaining expertise which will be useful when the system fails
24

Ease of future up-gradation
 Assembling Preparatory steps

Collecting Hardware and Software Modules

Collecting Tools

Choosing a non metallic surface work area and moisture free environment
 Caution
 Bill of Materials
 Assembling Sequence

System box preparation

Motherboard Stuffing

Motherboard installation

IDE Drives Preparation

Drive Installation

Daughterboard Installation

Cables Connection

Power Connection

Power Connection

BIOS Setup

Loading Software: Operating System and Special I/O Drivers
Preventive Maintenance
Answer Key
 Definition
 Peripherals – PM Types
 Problem Causes

Problem Sources

Dust

High Temperature

Electrical noise / Interference

Magnetic Fields

Corrosion
25

Power Fluctuations

Improper Handling
 Problem sources, Effects and PM Actions
 Peripherals

Keyboard

Printers
 General Precautions
Disk Operating System
Answer Key
 Definition

Single User OS

Multi user OS
 Anatomy of DOS
 Nucleus of the MS-DOS

IO.SYS

MSDOS.SYS

COMMAND.COM
 The Command Processor

Working of COMMAND.COM

Internal Commands

CLS

DIR

DEL Filename

COPY Source Target

DATE

TIME

TYPE Filename

VER

VOL

MKDIR Path

RMDIR Path
26

External Commands

FORMAT Drive

FDISK

LABEL

CHKDSK Drive

MODE Device

Print Command

Backup Command

Restore Command
 Special Files

CONFIG.SYS

AUTOEXEC.BAT
 Hoe DOS gets Control
DOS: Resource Manager
Answer Key
 Floppy Diskette

Physical organization

Logical Organization of the Disk Space
 Files Area
 System Area
 Boot Record
 File Allocation Table
 Root Directory
 How DOS creates, Reads or deletes a file
 Sub-Directory
DOS 5 & DOS 6 advanced features
Answer Key
 HMA, Extended Memory and UMBs
 What is the use of HMA and UMBs?
27
Virus
Answer Key
 Definition
 Virus: Types

Boot Virus

The File Virus
 Vaccine: The Cure

Detection

Removal

Immunization
 Precautions to be taken against virus
 Steps to be taken against a virus
Data Recovery
Answer Key
 Definition
 Data Recovery tools from DOS

UNDELETE

UNFORMAT
 Third Party Data Recovery Tools

Norton Utilities


Disk tool

Make a Disk Bootable

Recover from DOS’s Recover

Revive of a Defective Diskette

Mark a Cluster

Create Rescue Diskette

Restore Rescue Diskette
Norton Disk Doctor

Diagnose Disk

Common Solutions


Make a Disk Bootable

Recover from DOS’s Recover

Revive of a Defective Diskette
Exit Disk Doctor
28