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A+
Essentials Exam Cram Notes
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Download
A+ Essentials Practice Exams
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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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Blue
screen messages are also called STOP messages. You will not be allowed
to proceed, when a blue screen message appears. The most likely cause of
blue screen messages are:
1. Boot sector virus
2. IRQ/ IO address conflicts.
You can check for any boot sector virus, and also for any conflicting
IRQ / IO addresses.
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Bluetooth
conforms to its own standards, and not compatible with 802.11 standards.
Bluetooth is widely used
for communication between smart phones and other accessories or between
PDAs and information kiosks. The typical coverage for Bluetooth devices
is up to 30 feet.
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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.
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Both
System Information and Add/ Remove Hardware can be used to troubleshoot
hardware device problems on a Windows 2000 Professional computer.
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By
default, you can start recovery console 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.
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By
pressing <CTRL> <ALT> <DEL>, you launch the Security
Window in Windows 2000 OS. Note that in Windows 9X, it launches the task
manager. The Security Window in 2000 contains task manager.
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By
using latest Windows Update, it is possible to secure the Operating
System from any known bugs.
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Cat
6 cabling is recommended for Gigabit Ethernet networking.
CAT6 cable contains four
pairs of copper wire and unlike CAT5, utilizes all four pairs. CAT6
supports Gigabit (1000 Mbps) Ethernet. CAT5 enhanced (CAT5e), supports
short-run Gigabit Ethernet (1000 Mbps) networking and utilizes all four
wire-pairs.
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CD-R
stands for CD- Recordable. You can only record data onto a CD-R only
once. CD-RW stands for CD-ReWritable, and as the name suggests, you can
record data any number of times onto a CD-RW (subject to wear and tear).
CD-R is represented by two speeds (AxB), the former is the write speed
and the latter is the read speed. The write speed is always higher than
the write speed. Some typical CD-R speeds are as given below:
4X24,
8X32,
16X32 etc.
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CD-Rs
are of two types: single session and multi-session. A single session
CD-R can be used for a single session of recording. The CD is closed
after a single session of recording, and the remaining space on the CD
becomes un-utilized. A multi-session CD-R allows recording possible
during multiple sessions resulting in efficient use of space. A
multi-session CD-R can be closed after a single session if required.
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Centronix
IEEE 1284 is a standard for parallel printing.
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COM1
and COM2 on a computer use serial cable. The pin assignments are shown
below. The computer acts as a DTE(Data Terminal Equipment) and the Modem
acts as DCE (Data Communication Equipment).
Symbol ................ Signal name ............. DB9 Pin #
RX ....................... Received Data ............... 2
TX ....................... Transmitted Data............. 3
DTR .................... Data Terminal Ready........ 4
GND ................... Ground ........................... 5
DSR ................... Data Set Ready................ 6
RTS .................... Request to Send............... 7
CTS .................... Clear to send.................... 8
Normally, a DTE device connects to a DCE device. If you want to connect
two DTR devices, as you would do to hook up two computers via the serial
line to exchange files, the cable itself must have cross connections.
Such a cable is called null modem cable.
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CPU
throttling usually refers to reducing power consumption in CPUs by
lowering the clock frequency. When a processor gets overheated, CPU
throttling is enabled, and automatically lowers the CPU clock frequency
thereby reducing the power consumed by the CPU. Most of the modern day
processors support the CPU throttling technology.
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Ctrl+Esc
will pop-up Start menu in Windows 2000/XP.
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DDR
stands for Double Data Rate. It comes in 184-pin DIMMs. Note that Rambus
DRAM (known as RDRAM) also has 184 pins, but not compatible with DDR
SDRAM.
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Dial-up
Internet and DSL use copper wire for connecting to the Internet. In the
case of DSL, there is a distance limitation between the Hub and the
customer premises, beyond which the DSL may not work. Cable Internet
uses co-axial cable that connects to your cable TV. Satellite Internet
uses a satellite dish, and usually initial costs are more expensive.
Satellite Internet is commonly used when broadband connectivity is
required at remote locations that do not have traditional cable or DSL
Internet.
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Dial-up
offers the lowest speed among the other Internet access schemes. Cable
Internet uses co-axial cable and a cable modem to connect to the
Internet and offers highest download speeds up to a maximum of 3 Mbps
(theoretically, download speeds are much higher than this). This is
closely followed by Satellite Internet and DSL. The upload speed are
typically limited to 128 Kbps.
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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.
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DNS
stands for Domain Name System Server. DNS Server is the one responsible
for converting the Domain names to IP addresses.
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DOS,
Windows3.1 Windows 95/ 98 operating systems share the following
criteria:
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.
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Dot
matrix printer is suitable for printing multi-part forms.
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DVD
(stands for Digital Versatile Disk) comes in single layer (SL) or dual
layer (DL). They are also distinguished as single sided (SS) or double
sided (DS). There are four possible combinations:
DVD-S (12 cm, SS/SL): 4.37 GB capacity
DVD-9 (12 cm, SS/DL): 7.95 GB capacity
DVD-10 (12 cm, DS/SL): 8.74GB capacity
DVD-18(12 cm, DS/DL): 15.90GB capacity.
Further, DVD-S stores about two hours of video, where as DVD-18 can
store up to eight hours of video.
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Each
device in a SCSI chain need to have unique ID. For a 16-bit Wide SCSI,
there are 16 possible SCSI Ids, 0-15. A standard 8-bit SCSI can support
only 8 devices (including SCSI card), the Ids allowed are 0-7.
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EEPROM,
Electrically Erasable Programmable ROM is used to program dynamically.
EPROM, Erasable Programmable ROM can be erased with ultra violet light.
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Electrostatic
discharge (ESD) can damage the component at as little as 110 volts. CMOS
chips are the most susceptible to ESD. Static electricity builds up more
in cold and dry places. Use humidifiers to keep room humidity at about
50% to help prevent static build up.
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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.
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Ethernet
is based on CSMA/CD, which stands for Carrier Sense Multiple Access /
Collision Detect.
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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.
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Windows
2000 Service Pack 2 (SP2) and earlier versions of Windows 2000 do not
support 48-bit Logical Block Addressing (LBA). As a result, your drive
will be reported as 127-137 GB, even it is higher. This problem was
first corrected in Windows 2000 Service Pack 3.Important Although
support for 48-bit LBA is included in Windows 2000 Service Pack 3 (SP3)
and later, it is still necessary to create the registry changes as per
the OS manual. For Windows XP, ensure that Service Pack 1 or above is
installed.
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FDISK
can be used with MBR switch to replace the Master Boot Record with a
backup copy.
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File
names can be 255 characters long on a FAT, FAT32, and NTFS file systems.
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First
you need to partition the disk. A 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 need to be formatted.
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Floppy
disks can be used for backing up small amounts of data, such as a few
hundred KBs. It is preferable to use tape back up, since the data need
to be backed up is few hundreds of MB. Also, purchase a tape drive
cleaning kit, since a tape drive need to be cleaned regularly. You can
also consider using CDROM back-up.
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For
connecting to a 10BaseT Ethernet LAN, you need an RJ-45 connector at the
network end of the cable. The maximum length of the cable for 10BaseT
Ethernet is 100 meters (without repeater).
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For
effective communication, you need to spend roughly 50 percent of time
for listening to your customer
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Friction
feed is most commonly used with laser printers, and Inkjet printers.
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FTP
stands for File Transfer Protocol. FTP is used widely for file downloads
over the Internet.
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Given
below are some commonly used color depths and the number of bits
required to store the color information per pixel:
1 bit (mono) : 2 colors
2 bits: 4 colors
4 bits: 16 colors
8 bits: 256 colors
16 bits: 64K colors
24 bits: 16.7M colors
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Given
below is a list of Volume Types:
Volume Type Fault Tolerance Access Speed
Simple volume None Normal
Spanned volume None Normal
Striped volume None Fastest
Mirrored volume High Normal
RAID-5 volume Medium Fast
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If your
computer is running Windows NT 4 Work Station and several applications
are running on the computer. If you make a clean install, you need to
install the applications again. Therefore, it is recommended to do an
upgrade. However, make sure that the applications are compatible with
Windows 2000 and software upgrade packs are available for applications
where required. When you have very few applications that need to be
upgraded, it is recommended to do a clean install. Please note that
Windows NT Server computer can’t be upgraded to Windows 2000
Professional.
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Hibernate
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.
When you select Standby, the power to your screen, hard drive, and
peripheral devices is cut. However, the power to the computer's memory
(RAM) is maintained so your open files stay open. Shutdown basically
shuts down your computer completely. If you are going to be away from
your computer for an extended time or overnight, putting your system
into hibernate mode puts your system into an even deeper sleep than
Standby mode and is essentially just short of a complete shutdown.
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Hibernation
mode stores the current session on to the hard disk, and resumes the
current session when the computer is switched on.
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Hub:
A hub is basically a multi-port repeater. When it receives a packet, it
repeats that packet out each port. This means that all computers that
are connected to the hub receive the packet whether it is intended for
them or not. It's then up to the computer to ignore the packet if it's
not addressed to it. This might not seem like a big deal, but imagine
transferring a 50 MB file across a hub. Every computer connected to the
hub gets sent that entire file (in essence) and has to ignore it.
Bridge: A bridge is a kind of repeater, but it has some intelligence. It
learns the layer 2 (MAC) addresses of devices connected to it. This
means that the bridge is smart enough to know when to forward packets
across to the segments that it connects. Bridges can be used to reduce
the size of a collision domain or to connect networks of differing
media/topologies, such as connecting an Ethernet network to a Token Ring
network.
Switch: A switch is essentially a multi-port bridge. The switch learns
the MAC addresses of each computer connected to each of its ports. So,
when a switch receives a packet, it only forwards the packet out the
port that is connected to the destination MAC address. Remember that a
hub sends the packet out every port, and you can see how much more
efficient this it.
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IDE
(or EIDE or ATA or PATA), and SATA are two most commonly used interface
standards for connecting to the internal hard drives. SCSI is another
standard most commonly used when connecting hard drives in a Server
computer.
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