CompTIA® A+ Essentials Exam Notes : Cable Lengths, Slip, Smtp, And Others

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54)Serial cable maximum length is 50 feet Parallel cable maximum length is 10 feet Longer cable lengths may lead to some errors & garbage characters

55)Service Packs (SPs) are a collection of fixes in the following areas: security, application compatibility, operating system reliability, and setup. Latest Service Pack usually includes the updates contained in previous Windows 2000 service packs.

Shielded cables exhibit better interference rejection characteristics compared to unshielded cables.

56)SIMMs (Single Inline Memory Modules) have 72 pins on each side of the stick (30 pin in older 386/some 486 compatibles). SIMMs are 32 bits wide, and you need two 72-pin SIMM sticks (Minimum) on a Pentium class computer. This is because, the bus width is 64 bits in a Pentium class computer. Note that each side of each pin on a SIMM stick is same, where as each side of each pin on a DIMM (Dual Inline Memory Module) has separate signal flowing.

DIMM: Dual In-line Memory Module. DIMMs usually come in 168 pin configuration.

SIMMs need to be installed in pairs. On the other hand DIMMs can be installed one at a time. (Only one DIMM can support your system, whereas two SIMMs are required otherwise)

57)SLIP can't support DHCP. SLIP stands for Serial Line Internet Protocol. SLIP supports only TCP/IP where as PPP supports several other protocols..However, one advantage of SLIP is that it has less overhead compared to PPP.

SMTP is widely used e-mail standard on the Internet

SMTP can be used to upload mail over Internet to a Mail server. Note that POP3 is used to read email.

SMTP is used to upload mail to the mail server. POP3 is used for downloading mail from a mail server to a client machine running POP3 client.

SoDIMM (short for Small Outline DIMM), and MicroDIMM are widely used in laptops.

Software is considered malware (malicious software) based on how the software is intended to be used. Malware includes computer viruses, worms, trojan horses, spyware, dishonest adware, and other malicious and unwanted software

58)Some important port numbers are as given below:

1. FTP: 21, stands for File Transfer Protocol
2. Telnet: 23, stands for Telnetting from a remote terminal to a TelnetServer
3. SMTP: 25, stands for Simple Mail Transfer Protocol
4. HTTP/WWW: 80, stands for Hyper Text Transfer Protocol
5. POP3: 110, stands for Post Office Protocol

59)Some of the frequently encountered problems using laser printers and probable causes are as given below:

1. Speckled pages: The causes for this may be a. The failure to clean the drum after printing properly, or b. The drum might have developed scratches

2. Blank pages: The causes for white pages may be, A. The toner would have dried out, replace the toner. B. The transfer corona, that is responsible for transferring the toner to the drum might have failed. C. The High Voltage Power Supply (HVPS) failure will also result in white pages.

3. Ghosted Images: Ghosting occurs when previously printed pages are printed again, though much lighter than the present image. The most likely cause is that the erasure lamp might not be working properly, thus leaving some charges representing the earlier image left on the photosensitive drum before new image is written. Also check the cleaning blade, which is responsible for scaping the residual toner.

4. Smudged images: If the fusing fails, the toner will not bond with the paper. Check the halogen lamp responsible for heating.

60)Some of the important commands useful in trouble shooting TCP/IP networks are:

I. Ipconfig: Displays TCP/IP configuration values, including IP address, subnet mask, and default gateway.

II. Ping: This command can be used to verify whether the target ip address or host name is present. You need to specify the target IP address or host name.

III. route: Displays and manipulates route information.

iv: Tracert: Determines the route packets take to reach the specified destination.

SRAM - Statit Random Access Memory - Uses transistors to store information
DRAM - Dynamic Random Access Memory - Need to be refreshed to retain data.
ROM - Read Only Memory - Data in ROM can not be erased or changed
PROM - Programmable ROM - Once programmed, data can't be erased or changed
EPROM - Erasable PROM - Data can be erased by ultraviolet light and can be reprogrammed using a programmer.
EEPROM - Electronically Erasable PROM - Data can be erased electrically.Chip can then be reprogrammed. EEPROMs are frequently used to store BIOS.

SSID, short for service set identifier, a unique identifier attached to the header of packets sent over a WLAN that acts as a password when a mobile device tries to connect to the Access Point. The SSID differentiates one WLAN from another, so all access points and all devices attempting to connect to a specific WLAN must use the same SSID.

SSID needs to be configured on the laptop for connecting to the Access Point. The DHCP server typically supplies IP address, DNS server information, and subnet mask.

Standard Ethernet supports 10Mbps
Fast Ethernet supports speeds up to 100Mbps
Gigabit Ethernet supports speeds up to 1 Gbps

System Restore takes a "snapshot" of critical system files and some program files and stores this information as restore points. You can use these restore points to return Windows XP to a previous state.

61)TCP/IP protocol stack is installed by default when you install Windows 2000 on a computer.

TCP/IP is the protocol used when you are Telnetting to a remote host. HTTP is used for accessing the World Wide Web services.

Telnet is used for terminal emulation that runs programs remotely.

FTP is used to transfer files.

The automatic restart option in Windows XP is enabled by default. As a result, if there is any major error, the Operating System will automatically restart. This can be disabled using System applet in the Control Panel.

The best ways to find whether a new hardware is supported by your Windows OS is to check the manufacturer's documentation first, and then the Hardware Compatibility List (HCL).

62)The BIOS password is stored in CMOS memory that is maintained while the PC is powered off by a small battery, which is attached to the motherboard. Refer to the motherboard manual to find the jumper that clears the BIOS password. Alternatively, if you remove this battery, all CMOS information (including the BIOS password) will be lost.

The command "format a: /s" can be used to format the floppy disk in drive A, and at the same time make it bootable.

The command SMARTDRV /C forces SmartDrive to write out any write cached data. You can write delayed data even by pressing Ctrl+Alt+Del. If you Reset or Power Off/On, the delayed data will be lost.

The Complementary Metal-Oxide Semiconductor (CMOS) allows the computer to store the Real Time Clock (RTC)and other device information even after the computer is switched off and on. This is achieved by using a battery just for CMOS.

The connector types commonly used for Fiber Optic networking are SC,ST, or MIC connectors. IDC/UDC is used in Token Ring networks. RJ-45, BNC connectors are commonly used in Ethernet networking.

63)When a customer is explaining a complex problem that he has been facing, it is appropriate to take notes while he explains the problem. It will ensure that you do not miss any important points. It will also ensure the customer that you are seriously listening to what he is saying.

If your customer is expecting you at a specified time, it is appropriate to call the customer over phone, and inform him that you would be late.

The default spool folder is located at: Systemroot\System32\spool\printers. For example, if the OS is residing on C drive, the default location will be: "C:\\WINNT\System32\spool\printers".

You can access this location through:

Start -> Printers -> File -> Server Properties -> Advanced tab. Type in the new spool location over the default location.

The Device Manager lists all the hardware devices installed on your system. You can also update any existing drivers, as well as change the hardware settings. You use Add/ Remove Hardware to install new hardware. Accessibility options is primarily used to configure the keyboard, display, and mouse options on a computer to accommodate the users who are physically handicapped. The Add/ Remove Programs is used to install / uninstall 3rd party software. This is also used for installing / uninstalling Windows 2000 optional components.

The Device Manager provides the status of the devices installed in the system.

The File System Boot Sector is the first physical sector on any logical volume.

The first physical sector on any bootable hard disk contains Master Boot Record, MBR.

64)The following are major characteristics of a floppy drive:

1. The ribbon cable connecting the floppy drive to the mother board, is 34 wires wide.
2. There can be a maximum of two floppy drives in a PC
3. The floppy ribbon cable is distinguished easily from that of an IDE cable by a small twist in the cable. The purpose of the twist is to differentiate between floppy drive A and floppy drive B.

The following are most commonly used modem commands:

Modem commands-Command function
ATA ....................... Answer the phone
ATD ....................... Dial the phone, ATDT for Tone dialing, ATDP for Pulse dialing
ATH ....................... Hang up
ATZ ....................... Reset
AT&F ....................... Reset modem parameters and settings to factory defaults
AT&W ..................... Write the current parameter values and settings

65)The following are the 6 steps in the ElectroPhotographic (EP) print process of Laser Printer:

1. Cleaning: Cleaning the photosensitive drum includes residual toner left on the drum and removing the electrical charges left out on the drum. The physical cleaning is done with a rubber blade and the electrical charge cleaning is done with erasure lamps.

2. Charging: The next step in printing, is to charge the photo sensitive drum with high negative charge, this is done with the help of a corona wire.

3. Writing: A laser (type 3) sweeps the entire length of the drum, creating the static image of the matter to be printed. The places where the laser travel, the highly charges are nutralized. Other places of the drum, it remains highly negatively charged.

4. Developing: Now drum gets in close proximity to the toner. Because the toner is negatively charged, it gets attracted to the areas where the drum is neutral. It will not be attracted to the places where the drum is highly negatively charged. Thus the image of the page to be printed formed on the photosensitive drum.

5. Transferring: Now, the toner on the drum gets attracted toward the paper, by using highly positive charges developed on the surface of the paper. The "transfer corona" is used to generate highly positive charge on the paper surface and to attract the toner from the drum. Thus the image of the page to be printed formed on the paper. But still, the toner is loose and can get easily smeared.

6. Fusing: In order to permanently bond the toner particles to the paper, the paper is passed through rollers. One of the rollers, the non stick roller is heated by a high intensity lamp, generating the heat necessary to bond the toner to the surface of the paper.

The following are the types of backup:

Full backup: Here all files that have been chosen for backup are backed up, irrespective of whether the archive bit is set or not set. Archive bit is set (ON) after backup.

Incremental backup: Here only the files that have been created or have changed since the previous full or incremental backup will be backed up. The archive bit is set after a file is backed up. The next Incremental backup will backup files that have changed since previous full or incremental backup.

Differential backup: Here, the files that have changed or created since the last full backup will be backed up. Note that, unlike Incremental backup, the archive bit is not set on a differential backup. The result of this is that the next differential backup will include files that were backed up during earlier Differential backups.

66)The following are types of PCMCIA (PC card) cards:

1. Type I: 3.3 mm thick. Used for memory upgrade cards.
2. Type II: 5 mm thick. Modem and network cards. Some are combination Modem/NIC cards.
3. Type III: 10.5 mm thick. Used in PC card hard drives

The generic standard that defines wireless LAN technologies is 802.11. Specifically, the following standards exist:

a. 802.11: applies to wireless LANs and provides 1 or 2 Mbps transmission in the 2.4 GHz band.
b. 802.11a: an extension to 802.11 that applies to wireless LANs and provides up to 54 Mbps in the 5GHz band.
c. 802.11b (initially referred to as 802.11 or Wi-Fi): an extension to 802.11 that applies to wireless LAN and provides up to 11 Mbps transmission in the 2.4 GHz band.
d. 802.11g: applies to wireless LANs and provides 20+ Mbps in the 2.4 GHz band.

67)The widely used interface cables have the following pin count:

1. floppy-34 pin,
2. IDE-40 pin,
3. SCSI-50 pin,
4. SCSI Ultra wide-68 pin

The ISP provides the information on the SMTP, and POP server addresses. You need to feed this information to the mail client while configuring to send and receive e-mail.

The manufacturer specifies the field replaceable parts, and usually, the print heads and toner catridges are the only FRUs (Field Replaceable Parts).

The maximum recommended length of a serial cable for printing applications is 25 feet. Above this length, it may result in cross talk, or excessive fading of the signal.

68)The maximum specified transmission speed for 10BaseT Ethernet is 10Mbps. For 100BaseT, it is 100Mbps.

The most commonly used port for connecting digital camera to a desktop computer is serial port, and USB port is gaining popularity as more and more PCs support USB.

The most likely cause for sporadic movement of mouse is dirt. If dirt has entered the mouse, clean the dirt with IPA, or cotton wetted in soap water.

The most likely problem if you hear scratching sound of a hard disk is that the hard disk read/write head is scratching the disk surface. It often results in the total failure of the disk. If you find that you can still read/write to the disk, backup the hard disk and replace immediately.

The most probable cause that the screen is dumping garbled characters is that the communication settings are not correct. Check the speed, parity, start/stop bits etc. If the serial port parameters are correct, then you need to check the cable, such as straight/cross cable and the pin connections.

69)The motherboard displayed has the following expansion slots:

PCI slots : 5 (distinguished by white color, usually the number of PCI slots available on a motherboard varies from 3 to 6)
ISA slots: 2 (distinguished by black color, longer than PCI slots, placed next to PCI slots.)
AGP slot: 1 ( The single slot, next to 5 white PCI slots is AGP slot in brown color. Note that there will be only one AGP slot)

The MSDS contains wealth of information including Product and Company information, First aid measures, Handling and storage, Physical and chemical properties, etc.

The primary partition can be made bootable, by marking partition as active. The extended partition can not be marked as active partition.

The red stripe signifies wire going to pin number 1. Also, a floppy cable has 34 wires where as an IDE cable has 40 wires. Ultra IDE cable has 80 wires, and handles better speeds compared to IDE cable with 40 wires. The additional wires are introduced to reduce noise and thereby improving speed.

The Registry contains the important information about the devices and applications. Any failure to backup the registry may require re-installation of the complete system.

70)If you install a second hard drive, and assuming that the first hard drive has C, D, and E partitions, and the second drive has tow partitions, the revised drive assignment looks as follows:

Drive 1: C (Primary Partition), E (First logical Drive), F (Second logical Drive)
Drive 2: D (Primary Partition), G( for Logical drive on Extended Partition)

In addition, please note the following:

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

71)The smallest addressable unit in a hard disk is a cluster.

The storage capacity of various types of floppy disks that you need to know as part of A+ certification is given below:

5 1/4" ---DSDD----360KB
5 1/4" ---DSHD----1.2MB
3 1/2" ---DSDD----720KB
3 1/2" ---DSHD----1.44MB
3 1/2" ---DSED----2.88MB
DSDD: Double Sided Double Density
DSHD: Double Sided High Density
DSED: Double Sided Extra Density

The switch /s will make all the files and sub directories to be marked as archive.

72)The table below compares various video types:

Video monitor -----Max. Color depth ------Max. Resolution
CGA -------------------16 Colors-----------------160X100
EGA--------------------64 colors------------------640X350 (Graphics Mode)
VGA-------------------256 colors-----------------640X480 (Graphics Mode)
SVGA-----------------16 Million Colors------1280X1024 or even more

While cleaning a computer CPU box, the use of compressed air is most appropriate. Use of vacuum cleaner may tend to create ESD. A nylon brush also creates electrostatic charges. Soap water is not recommended to clean PCAs.

73)The various CD speeds are as below:

For normal CD drives:
16X, 32X, 48X, 52X etc. Format: [read speed]X
For CD-R drives:
4X24, 8X32, 16X32 etc. Format:[write speed]X[read speed]
For CD-RW:
12X10X32 etc.
Format: [write speed]X[re-write speed]X[read speed].

The various file systems supported by Windows 2000 are:

3. FAT: Also called FAT16, supported by all Microsoft Operating Systems.
4. FAT32: Also supported by Win 95 OSR2 and Win98
6. NTFS: This is not supported by Win95/98
7. CDFS (Compact Disk File System, used to access CDs)
8. UDF (Universal Disk Format, used to access DVDs)

74)There are 3 types of PCMCIA cards:

Type I cards have thickness of 3.3mm
Type II cards have thickness of 5.0mm
Type III cards have thickness of 10.5mm
All PC cards have dimensions of 85.6mm by 54 mm.

Each type of card uses the same 68-pin connector (a pin is a conduit inside a port that the computer uses to access peripherals connected to that port), so the cards are downward compatible. That means if you have a Type III slot or socket on your notebook computer you can connect a Type II card as well, and if you have a Type II slot, you can connect a Type I card in that slot. A Type III card will not fit in a Type II slot, however.

75)Type I PC cards are generally used for memory cards

Type I PC cards are generally used for memory cards
Type II PC cards are generally used for Network cards, Modem cards etc.
Type III PC cards are generally meant for rotating mass storage devices such as removable hard disk, CD ROM.

Thin co-axial and thick co-axial cables have conductive grounding sheath surrounding the center conductor. Therefore, the electromagnetic interference (EMI) is significantly less.

To access a file, the correct UNC path is \\MYCOMPUTER\DIRS\MYDIR\MYFILE

Syntax: \\Computername\sharename\path\filename

76)To achieve proper USB connectivity six basic system elements must be present and working correctly.

1) Support from the BIOS
2) Support from the Operating System
3) Physical USB ports
4) A USB Device
5) The correct USB cable for the device
6) Drivers either from the OS and/or the peripheral maker

To clean a keyboard, soak it in a distilled demineralized water as soon as possible after the spill. Take precaution to remove the keyboard before doing so, and dry it before connecting back.

77)To connect a USB device,

1. The computer supports USB.
2. The USB should be enabled in the BIOS,

If both the above conditions are met, USB Controller is listed in the Device Manager. If it's not listed in the Device Manager, you can suspect that the USB was not enabled in the BIOS.

To insert a new file extension in your Windows computer, you use Windows explorer, and select the application. Then, Tools -> Folder Option -> File Types. Configure the extension appropriately.

To make floppy in drive A bootable, the command SYS A: should be given.

To measure DC current, open the circuit at the point where you want to measure the current. Place the multimeter probes in series with the circuit.

78)Token Ring network can support data transfer at 4 Mbps or 16 Mbps.

Token Ring networks use Multi-Station Access Unit (MAU).

Token Ring was created by IBM, and standardized by IEEE under the 802.5 specification. The original IBM Token Ring specification uses IBM Class 1 STP cabling with IBM proprietary connectors. This connector is called the IBM-type Data Connector (IDC) or Universal Data Connector (UDC), and is male nor female.

TRACERT command can be used to determine the path that a packet takes while traversing on the network before reaching the destination.

Under FAT file system, the maximum size of a cluster is 32 KB and the maximum number of clusters is 65536. Therefore, the maximum size of a partitions is the number of clusters multiplied by the max size of the cluster, which is equivalent to 2 GB. Remember that 1 KB = 1024 bytes.

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