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Complete Parts and Function of Computer Keyboard

BELOW ARE THE MOST PARTS AND FUNCTIONS OF THE COMPUTER KEYBOARD THAT COMMONLY USED. A computer keyboard is used to enter commands of...

Basic Microsoft DOS Command of Computer

BASIC INTERNAL DOS COMMAND OF TECHNICIAN
THE INTERNAL DOS COMMAND: The basic DOS Command that could help to you how to manage files using the MS-DOS.And may also as your pointers for the exam of NC2.As a Computer Technician it is very needed how to use the MS-DOS operations whenever the windows operating system was damaged or corrupted.

As of now we have 7 or 8 operating systems of Microsoft Windows.From windows 95 to windows 8, its started from the graphical user interface of those computer’s before.Which is IBM compatible and can support multi media or a movie files.But what is this operating systems and how is it important of the computer systems?, “particularly installed on microcomputers in order for the user to easily manipulate the data in the system and to run the system and its parts and devices simultaneously”. “And the MS-DOS serves as the backbone of windows operating system when the main OS is disabled or uninstalled.And also used to access data and settings in the computer.”

There are different ways in opening the MS-DOS, either win xp or win 98.You need to follow this simple steps:
  1. In win XP
  • click start button/click run/type in the bar CMD(means command mode)
  • press enter key
Also you can use the advance menu of the operating system once it turn on or restart
  • during bootup or power up, once POST is being displayed press F8 key
  • After a few seconds the advance menu will appear
  • select “safemode the computer with command prompt
  • the computer will boot in safemode process wait until the MS-DOS command line will appear.
Using also your CD/DVD installer you can access the command prompt during start up
  • Just power your computer
  • Enter the BIOS setup
  • setup your boot sequence, CD/DVD ROM
  • Press F10 to save your settings
  • Once POST being displayed press any key to load the startup files
  • Once the screen is blue and prompted to 3 options, select option number 2
  • Press 1 once enter in DOS Mode(if administrator password need to enter just type it)
  • Once you are in command line you are ready for your DOS command
There are two types of DOS command
  1. Internal DOS commands-this type of DOS command called also as resident commands that resides in the memory of computer that can be easily access anytime.
    • DIR- use to find out what files are on a diskette or hard drive
    • REN-rename files
    • CLS- clear the screen, used mostly in batch files
    • COPY-make copies of files
    • VER- tells what version of DOS you are using
    • DEL- erase(delete)files
    • MD,RD,CD- command lines to make,remove,and change the default specified directories
    • Root directory symbol (\):when leading used to indicate “starting from the root directory…” and as a separator when listing successive directories.Using wild card(?),(*):When designating groups of files.? is a single-character wild card, and * is a multiple-character wild card.DOT(.)and double dot(..):A single dot means the same as *.* when referring to current directory.
Exercise 1: DIR- displays files and directories inside a disk
switches:
/P-displays one screen then pause
/w-displays in wide screen
/A-displays files and directories including hidden files
/S-displays the list of file and directory names in all subdirectories
/O-sort order specifies the order in which the DIR displays file and directory names.
MINUS SIGN(-) reverse action of the order value
N sorts alphabetically
E sorts alphabetically by extension
D sorts by date and time,earliest time first
S sorts by size, smallest first
G sorts with directories grouped before files
  • running in command line
c:\>DIR 
C:\>DIR /P
C:\>DIR /P/W
C:\>CLS
C:\>VER
C:\>MD EXER
C:\>DIR
C:\>CD EXER
C:\EXER>DIR
C:\EXER>MD PRAC
C:\EXER>DIR
C:\EXER>CD PRAC
C:\EXER\PRAC>
EXERCISE 2: CD-Change to different directory.
                     Switches:
                                   \-Refers to the root directory
                                   ..-Level higher than the current directory
                                   .-Specify the current directory
                                   Path-the directory or subdirectory name
To change directory one level higher
  • C:\EXER\PRAC>CD..
  • C:\EXER>
  • C:\EXER>CD PRAC
  • C:\EXER\PRAC>
To change to root directory
  • C:\EXER\PRAC>CD\
  • C:\>
Adding path to CD command
  • C:\>CD DOS
  • C:\DOS>CD\EXER
  • C:\EXER>
EXERCISE 3: RD- Remove directory
  • C:\EXER>RD PRAC
  • C:\EXER>DIR    (directory PRAC is removed)
EXERCISE 4: COPY- Copies one or more files to the location you specify.
  • C:\EXER>COPY C:\AUTOEXEC.BAT
  • C:\EXER>DIR
EXERCISE 5: Command copy with source path and target path
           At root directory C:
  • C:\>COPY C:\EXERCISES\*.* C:\PRAC
  • C:\>CD PRAC
  • C:\PRAC>DIR
EXERCISE 6: DEL- Delete or erase file(s)
          To delete one file
  • C:\EXER>DEL PAYROLL.XLS
  • C:\EXER>DIR
          To delete all files
  • C:\EXER>DEL.
  • C:\EXER>DIR
EXERCISE 7: TYPE- Displays the contents of a text file
          At a root directory C:
  • C:\>TYPE AUTOEXEC.BAT
  • C:\>TYPE CONFIG.SYS

TIPS!


  • You need also to learn the EXTERNAL DOS COMMAND that very use to all computer technicians and technologies.

What is Power Supply Unit of Computer?

WHAT IS POWER SUPPLY OF COMPUTER?
A power supply of computer abbreviated as P.S.U or power supply unit is the most important hardware unit of computer.The one who adapt the distribution of both current and voltages for standard used of computer systems.

The power supply unit converts the standard wall outlet electricity,typically 220 or 110 VAC or voltage alternating current.And it’s divided into low level voltages through the secondary circuits as outputs for the systems of computer.Each subassembly draws some electricity which is measured in watts.The typical Advance Technology(AT) and Advance Technology Attachment(ATX) clone come equipped with a 150 to 200 watts and the new form factor and more enhance processor needs a value of 400 to 900 watts.Most specially of the new attachment called SATA and firewire.Typically there are 20 pins of the output of the PSU, see the table below.

PIN
WIRE COLOR
SIGNAL
PIN
WIRE COLOR
SIGNAL
1 ORANGE 3.3 V 1 ORANGE 3.3V
2 ORANGE 3.3 V 2 -12
3 BLACK GND 3 BLACK GND
4 RED 5 V 4 PS_ ON
5 BLACK GND 5 BLACK GND
6 RED 5 V 6 BLACK GND
7 BLACK GND 7 BLACK GND
8 POWER GOOD 8 -5 V
9 5V_SYSTEM BOARD 9 RED 5 V
10 YELLOW 12V 10 RED 5 V

Variations in electrical power(such as spikes and surges) can damage your computer.For this reason be sure to use a surge protector on your computer.

When recommending or buying a power supply, check the following considerations.

LOW NOISE LEVEL- The most usual disturbance of a power supply is the FAN.There are higher required revolution or revolution per minute(RPM) to meet the standard level of the temperature.Some fans are quieter than others, unfortunately, they all make some noise.Before purchasing a computer or power supply, check to make sure that the fan is not excessively noisy.

AUTOMATIC OVERLOAD AND OPEN CIRCUIT SHUTDOWN- check if the power supply has overload protect.If a short or overload develops in the computer,the power supply will save itself by shut downing itself automatically.This features may save other components, as well as the power electricity consumption.

1. AVR (AUTO VOLTAGE REGULATOR)- AVR is a device use or equipped to regulates the current/voltages fluctuations.Which generates,monitors, and analyzes power for a more exact and reliable power for computer equipments capable of:
  • sense over voltage and under voltage of the input line
  • sense over current of the load
  • sense aberrations in the power lines such as: intolerable spikes transients,surges and sags,slow average fluctuations
  • maintains the output voltage within its tolerance(±1%)of the nominal voltage
  • responds/recover to input variations within one cycle or 0.16 seconds,usually termed as responds time.
  • audio/visual monitors or warnings
  • cut off power when such aberrations occur protecting the circuit itself and the computer and equipments.
  • delay time
TYPES OF AVR
SERVO MOTOR TYPE
MECHANICAL AVR
ELECTRONIC AVR
2. UNINTERRUPTED POWER SUPPLY UNIT OR U.P.S-
FUNCTIONS OF UPS
  • Provides continues power to critical line when power blockout occured
  • Improves/regulates quality fluctuations to sensitive loads
  • Protects load from voltage fluctuations
  • Noise and spikes caused by lighting
  • Electrical machines,appliances and motors                     
EQUIPMENTS THAT NEEDS
  1. Computer servers and on load in the event of power line failure terminals
  2. Telephone systems
  3. Communication systems
  4. Process control equipments
  5. Instrumentation equipments
  6. Security systems
  7. Life support systems
  8. Nuclear power parts
  9. Other sensitive electronic equipments
  10. Micro computers
UPS PARTS:  
1. Rectifier charger
  • converts AC to regulate DC
  • charges the battery
  • input power to inverter
2. Storage Battery
  • DC input to the inverter during voltage drops or upon failure of the normal AC line.

TIPS!
  • Use power rated P.S.U. if you have maximum hardwares in your computer and high rated processor like Intel i7 core.
  • Avoid overclocking of the processor if your not sure in CMOS/BIOS settings of your motherboard.

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