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A+
Essentials Exam Cram Notes
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Download
A+ Essentials Practice Exams
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ECP
(Extended Capability Port) is a joint effort by Microsoft and HP. It has
less control overhead and best suited for transferring large chunks of
data, such as between the computer and laser printer.
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Ensure
proper cable connection after replacing floppy disk drive. Some points
to remember when you replace a FDD,
1. Check to see if the cable polarity / orientation is OK
2. Check whether the cable is properly seated and not loose.
3. Don't force the cable, that it may result in damage to pins
Interface cables used:
floppy-34 pin,
IDE-40 pin,
SCSI-50 pin,
SCSI Ultra wide-68 pin
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If
you encrypt a folder on an NTFS volume, all files and subfolder created
in the encrypted folder are automatically encrypted. Therefore, it is
recommended that you use encryption at the parent folder level.
Also note that you can’t encrypt a file or folder that is compressed.
If you want to encrypt a file or folder that is compressed, you need to
first decompress the file or folder and then encrypt. Only NTFS volumes
support file or folder encryption.
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Monitors
accumulate very high static charges and need to be handled very
carefully. Before attempting any repair, it is imperative to discharge
any accumulated charges on the monitor. You can use a jumper, one end of
which is grounded, and touch the other end of the jumper wire to the
anode of the monitor. While doing so, ensure that you are not in direct
contact with the jumper wire or the anode. You can use a screw driver or
a nose pliers with rubber handle for this purpose. A "POP"
sound can be heard when the static charges accumulated on the anode lead
getting grounded through the jumper wire. Remember, that if you get in
contact with the static charge, it may lead to severe burns or even
fatal accident!
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Never
wear a wrist strap when working on monitors. Monitors contain very high
voltages, sometimes fatal to human, even when the power is turned off.
If you are wearing wrist strap, the human body work as a conduit to
discharge the electric charge.
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The
following devices require periodic cleaning:
1. Floppy drives
2. Tape drives
3. Printers
4. Mouse
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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 less secure.
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When
signals are transmitted over a long distance, there will be ohmic
losses, which result in loosing the strength of the signals. This is
known as attenuation. Amplification is opposite of attenuation.
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While
preparing for dual boot with Windows 2000 Professional, note the
following points:
1. Windows 2000 must be installed on a separate volume. If a separate
volume is not available, repartition the hard disk suitably, and
reformat. You also need to take suitable backup.
2. If you want to have dual boot between Windows NT 4 and Windows 2000
as the only operating systems, ensure that Service Pack 4 is installed
on Windows NT 4. This is required since Windows 2000 upgrades the NTFS
to NTFS 5. NT4 requires Service Pack 4 to read and write to NTFS 5.
3. You must install Windows 2000 only after installing MS-DOS or Windows
95.
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.COM,
.EXE, .BAT files are executable files.
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+5
and +12 volts are the DC voltages commonly found on PCs
80386/486 operate at +5v
Pentium and above operate at +3.3v
Power supply wires - yellow=+12v, blue=-12v, red=+5v, & white=-5v
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1 KB
= 1024 bytes
1 MB = (1024 X 1024) bytes
= (1024X 1 KB) bytes
= 1,048,576 bytes
1 GB = (1024 X 1024 X 1024 )bytes
= (1024 X 1 MB) bytes
= (1024 X 1024 X 1 KB) bytes
= 1,073,741,824 bytes
KB stands for Kilobyte
MB stands for Megabyte
GB stands for Gigabyte
Byte is represented by "B" as in MB
Bit is represented by "b" as in kbps
One byte is 8 bits
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Computer viruses:
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,
is the 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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10BaseT
Ethernet complies with IEEE standard 802.3 and requires an RJ-45
connector to connect to the NIC.
10Base2 network, also known as Thin-net, uses BNC connector to connect
to the NIC.
A 10BaseT cable can
extend up to 100 meters without the use of a repeater
10Base2 network uses thin
coaxial cable and need to be terminated with a 50 ohm termination at
both the ends.
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144-pin
small outline DIMM (SO DIMM) is commonly used in notebook computers.
144-pin micro-DIMM is still smaller than the so-DIMM and used in
sub-notebook computers. 72-pin SODIMM was used in older laptops.
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256MB
PCI Express is recommended for computers that use high-end video
applications.
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802.11b
operates at 2.4 GHz, while 802.11a operates at 5 GHz. Typical data rate
for 802.11b is 11 Mbps where as it is 54mbps for 802.11a.
802.11b is compatible
with 802.11g. 802.11a is not compatible with 802.11b or 802.11g.
Bluetooth is entirely a different protocol standard, and is not
compatible with any of the 802.11 standards.
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A CD
can be recovered from any minor scratches by using polishing chemicals.
But it does not guarantee repair. Only way to safeguard is to make a
back-up copy of the CD.
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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.
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A
connection device that is plugged into a computer's serial/parallel port
in order to perform a loopback test is known as a loopback adapter.
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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
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A
good fuse will show close to zero ohms ( typically less than 1 ohm). A
bad fuse, will have open contact, and will show open.
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A
hard disk should never be low level formatted at the customer premises.
It is highly recommended that it is done at the manufacturer's or at any
authorized center.
It is very cumbersome to change the partition sizes, once the hard disk
is partitioned and used. It may require backing up all the data and
restoring after repartitioning.
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A
work station/PC very commonly connects to a LAN by means of an RJ-45
connector on a LAN card (Also known as NIC, or Network Interface Card).
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A
hub is used as a concentration point for connecting together all the
segments in a 10BaseT network. Another network devices that is used
extensively for this purpose is a switch.
NIC (Network Interface Card) resides inside the PC cabinet.
A repeater is used for joining two or more Ethernet segments. A repeater
can extend the distance over which the signal can travel without loosing
out due to attenuation.
50 Ohm termination is normally used at the ends of a 10Base2 network to
prevent signal reflection at the ends of the cable.
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A
Network Interface Card is required to be present in the PC to
communicate over a LAN. A switch or a Hub may be required or may not be
required depending on the network configuration. For example, if you
have 10Base2 (Thinnet) network, you may not need a Hub or a Switch.
Router is required only when there is routing involved.
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A
router for Internet sharing is normally configured using web browser.
High-end routers may provide option for terminal connectivity, wherein
you can connect a terminal, and issue commands for configuring the
router.
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A
Secure Digital (SD) card is a small memory card used to make storage
portable among various devices, such as cellular phones, PDAs, digital
cameras, music players, and personal computers. It uses flash memory to
provide nonvolatile storage, which means that a power source is not
required to retain stored data.
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A
SIMM has a single row of 72 contact fingers, each making contact on both
sides. An older version of SIMM card contain 30pins, and were used in
386 and 486 machines.
A DIMM (Dual-Inline Memory Module) has two rows of connecting fingers,
one row on each side, and the total number of contacts are 168.
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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.
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Active
link LED on a network card is an indication that the link is up. You
will be able to ping the local host even without the network
connectivity. Device Manager NIC status not necessarily ensures that the
network cable is plugged properly in to the NIC.
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Active
listening focuses on who you are listening to, in order to understand
what he is saying. As the listener, you should then be able to repeat in
your own words what they have said effectively. This does not mean you
agree with, but rather understand, what they are saying.
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AMR
slot: AMR stands for Audio Modem Riser. AMR is a riser card that
supports sound or modem function. With increasing CPU computational
power, the digital processing job can be implemented in main chipset and
share CPU power.
CMR slot: CNR stands for Communication Network Riser. CNR is a riser
card specification that supports V.90 analog modem, multi-channel audio,
phone-line based networking, and 10/100 Ethernet based networking. The
digital processing is implemented in main chipset and share CPU power.
A modem can also be inserted using PCI slot. But, in such case, it will
not be using onboard audio CODEC or CNR digital controller. The AMR card
primarily attends to conversion of analog signals to digital and visa
versa. Slot I is associated with CPU slots.
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An
IP address is considered private if the IP number falls within one of
the IP address ranges reserved for private uses by Internet standards
groups. These private IP address ranges exist:
10.0.0.0 through 10.255.255.255
172.16.0.0 through 172.31.255.255
192.168.0.0 through 192.168.255.255
Private IP addresses are typically used on local networks including
home, school and business LANs including airports and hotels.
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An
UPS is desired to be purchased for any critical and un-interrupted use
of computers. It has the following benefits:
1. Provide protection against small surges
2. Filters noise from entering the computer
3. Provide power to the computer during line power failure
4. Give stable power to computer, even when the line power is unstable.
Note that the UPS can give un-interrupted power only for a fixed amount
of time under a given load, in the absence of line voltage.
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Anti-virus
software, and anti spy-ware software can be used to clear malicious
programs from a computer. Also, note that you need to install up-to-date
Service Packs, and patches.
Anti-virus update files
are traditionally called as “Definitions”.
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If a
PC becomes slow, as a first step, you need to run Disk Cleanup and Disk
Defragmenter. Additionally, you can consider adding a second hard drive
or more memory.
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As
the humidity decreases, static build up will increase and vice versa. A
level of 50% is considered safe. Below 50% humidity, static build up
will be more.
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Asynchronous
serial communication uses Start-bit/Data-bits/Stop-bit. A modem
connecting to the Internet is a typical asynchronous device.
Synchronous communication uses clock signals to transfer information.
Does not use start/stop bits. Synchronous communication is normally used
for high speed data transfers.
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AT
motherboards were discontinued in the mid 1990s. The AT motherboard can
be distinguished by the position of key board plug and power socket.
Also, it has only a key board connector on board and doesn't support
other ports for mouse or printer. Baby AT is a form of AT motherboard
with reduced dimensions. AT motherboard is also called Full AT. ATX
mother boards have serial and parallel ports to support printer, mouse
and also USB support is provided. ATX has one rear plate that enables
acess to all necessary ports. Also, ATX uses one P1 power connector
instead of P8 and P9 connectors. The one shown in the exhibit is an ATX
motherboard.
ATX power supply provides
three different voltages:
3.3Volts, 5Volts, and 12Volts.
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Automated
System Recovery (ARS) requires that a system backup be taken using
Windows XP Backup utility.
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Batteries
contain environmentally hazardous chemicals and therefore, should not be
disposed through dust bit. Always refer to the manufacturer's
instructions or the relevant State guidelines. The same is true when you
are disposing chemical solvents.
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