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Home >Comptia >A+ >StudyNotes-2 CompTIA Home | Practice Questions | Resources | Books | CertNotes
CompTIA® A + Certification
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. You can check for any boot sector virus, and also for any conflicting IRQ / IO addresses. 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. 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. Both System Information and Add/ Remove Hardware can be used to troubleshoot hardware device problems on a Windows 2000 Professional computer. By default, you can start recovery console using, 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. By using latest Windows Update, it is possible to secure the Operating System from any known bugs. 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. 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: 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. 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). 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. 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. 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. 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 following
criteria: 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: Further, DVD-S stores about two hours of video, where as DVD-18 can store up to eight hours of video. 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. 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. 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. 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. 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. 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: Given below is a list of Volume Types: 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. 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. Hibernation mode stores the current session on to the hard disk, and 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 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. 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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