A+ Certification, awarded by CompTIA®
organization is the most widely recognized certification
in the area of PC hardware and software technologies. To
attain A+ certification, one need to pass 2 exams, namely,
A+ Core Hardware Technologies, and A+ Operating Systems
Technologies. These exams basically test the skills in assembling
a computer, troubleshooting, and the ability to work with
various operating systems. Linux is not included in the
A+ Certification Operating Systems exam, as it has an exam
of its own (Linux+ Certification), offered by CompTIA. The
exam cram offers several final preparation points for candidates
intending to appear for the A+ test. Latest objectives are
available from Comptia.com website.
Download
A+ practice
tests from SimulationExams.com
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31. Uninterrupted Power Supply (UPS):
An UPS is desired to be purchased for any critical and
un-interrupted use of computers. It has the following benefits:
- Provide protection against small surges
- Filters noise from entering the computer
- Provide power to the computer during line power
failure
- 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.
32. The following are types of PCMCIA (PC cards) cards:
- Type I: 3.3 mm thick. Used for memory upgrade cards.
- Type II: 5 mm thick. Used for modem and network
cards. Some are combination Modem/NIC cards.
- Type III: 10.5 mm thick. Used in PC card hard drives
33. Computer Cache Memory:
Level 1 cache is internal to the processor, and level 2 cache
is external to the processor, it resides on the motherboard.
In case of Pentium II, L2 cache is built into the cartridge.
34. CPUs and features:
| Processor |
Socket type |
Register |
Data Bus |
Address Bus |
| 8088
|
DIP
|
16 bit
|
8 bit
|
20 bit
|
| 80286
|
LLC/PGA/PLCC
|
16 bit
|
16 bit
|
24 bit
|
| 80386SX
|
PGA
|
32 bit
|
16 bit
|
24 bit
|
| 80386DX
|
PGA
|
32 bit
|
32 bit
|
32 bit
|
| 80486SX
|
PGA
|
32 bit
|
32 bit
|
32 bit
|
| 80486DX
|
PGA/SQFP
|
32 bit
|
32 bit
|
32 bit
|
| Pentium
|
Socket 5 SPGA/ Socket 7 SPGA.
|
64 bit
|
64 bit
|
32 bit
|
| Pentium Pro
|
Socket 8 SPGA
|
64 bit
|
64 bit
|
32 bit
|
| Pentium II
|
SEC Slot 1
|
|
|
|
| Pentium III
|
SECC-2 / PPGA or FC-PGA
|
|
|
|
CPU models 80486SX, and above contain on board cache memory.
Pentium Pro and above have onboard L2 cache.
35. Bits and Bytes:
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
36. Printer parallel ports come in the following varieties:
- Unidirectional: Here, the data travels only from the
computer to the peripheral (printer) device.
- Bi-directional: Here, the data travels both from the
computer to the peripheral device and vice-versa.
- ECP (Extended Capability Port): ECP mode offers bi-directional
data transfer, as well as DMA for data transfer.
- EPP (Enhanced Parallel Port): In addition to bi-directional
features, it offers an extended control code set.
37. Laser printers:
The following are the 6 steps in the ElectroPhotographic
(EP) print process of Laser Printer:
- 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.
- 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
- 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 neutralized. Other places of the drum, it remains highly
negatively charged.
- 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.
- 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.
- 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.
Some of the frequently encountered problems using laser printers
and probable causes are as given below:
- 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.
- 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.
- 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.
- Smudged images: If the fusing fails, the toner will
not bond with the paper. Check the halogen lamp responsible
for heating.
38. Impact printers are capable of printing multipart forms,
since they can give necessary impression to print to multiple
forms simultaneously. ECP (Extended Capability Port) has less
control overhead and best suited for transferring large chunks
of data, such as between the computer and laser printer.
39. The interface cables used widely have the following pin
count:
- floppy-34 pin,
- IDE-40 pin,
- SCSI-50 pin,
- SCSI Ultra wide-68 pin
40. One good way of determining a bad power supply is that
the fan will not rotate. Also, the computer will not boot and
the LED s indicating the speed will be OFF.
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