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.
18)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.
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.
19)Centronix IEEE 1284 is a standard for parallel printing.
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.
20)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.
Ctrl+Esc will pop-up Start menu in Windows 2000/XP.
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.
21)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.
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.
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.
22)DNS stands for Domain Name System Server. DNS Server
is the one responsible for converting the Domain names to
IP addresses.
DOS, Windows3.1 Windows 95/ 98 operating systems share
the followingcriteria:
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.
Dot matrix printer is suitable for printing multi-part
forms.
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.
23)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.
EEPROM, Electrically Erasable Programmable ROM is used
to program dynamically.
EPROM, Erasable Programmable ROM can be erased with ultra
violet light.
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.
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.
Ethernet is based on CSMA/CD, which stands for Carrier
Sense Multiple Access /Collision Detect.
24)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.
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.
25)FDISK can be used with MBR switch to replace the Master
Boot Record with a backup copy.
File names can be 255 characters long on a FAT, FAT32,
and NTFS file systems.
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.
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.
26)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).
For effective communication, you need to spend roughly
50 percent of time for listening to your customer
Friction feed is most commonly used with laser printers,
and Inkjet printers.
FTP stands for File Transfer Protocol. FTP is used widely
for file downloads over the Internet.
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
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
27)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.
28)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.
29)Hibernation mode stores the current session on to
the hard disk, resumes the current session when the computer
is switched on.
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.
30)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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