Showing posts with label HARDWARE COMPONENTS. Show all posts
Showing posts with label HARDWARE COMPONENTS. Show all posts

Saturday, June 26, 2021

WHAT TO DO WHEN A COMPUTER FREQUENTLY RESTARTS?

 COMPUTER FREQUENTLY RESTARTS



WHAT TO DO WHEN COMPUTER FREQUENTLY RESTARTS.  WHAT ARE THE REASONS FOR ITS PERFORMANCE DEGRADATION?  LET US SEE!


CAUSE NO 1

CPU OVERHEAT SOLUTION --> CHECK THE CPU TEMPERATURE FROM BIOS.  IF THE CPU TEMPERATURE IS HIGH, EJECT THE CPU FAN AND CLEAN IT PROPERLY WITH COMPRESSED AIR AND BRUSH.   APPLY THE RIGHT COOLING PASTE WITH A PIECE OF CLOTH.


NOW APPLY GOOD QUALITY COOLING PASTE WITH A THERMAL COMPOUND OVER THE PROCESSOR.  ATTACH THE HEAT SINK AND FAN AND CHECK THE TEMPERATURE AGAIN.  IF THE CPU FAN SPEED IS LOW AFTER CLEANING , CLEAN THE FAN WITH ISOPROPHYL ALCOHOL, DIESEL AND WHITE PETROL.


NOW ATTACH THE FAN AGAIN CHECK THE FAN SPEED IF IT IS SAME AS BEFORE REPLACE THE FAN.


CAUSE NO 2

VIRUS --> IF THE PROBLEM IS RELATED TO VIRUS.  INSTALL A GOOD QUALITY ANTIVIRUS SOFTWARE (AVAST, AVG AND QUICK HEAL)ETC AND SCAN THE SYSTEM.


CAUSE NO 3

RECENTLY INSTALLED A SOFTWARE, HARDWARE, DEVICE DRIVER.  DRIVER UPDATE

SOLUTION :- ASK THE USER FOR RECENTLY INSTALLED SOFTWARE, HARDWARE AND DEVICE DRIVER.  IF HE OR SHE DOES, YOU NEED TO GO TO THE SAFE MODE AND UNINSTALL THAT SOFTWARE OR DEVICE DRIVERS.


TO GO TO THE SAFE MODE

PROCESS NO 1 ––> RUN-->MSCONFIG-->BOOT TAB-->SAFE BOOT--> APPLY -->OK -->RESTART


 TO GO TO THE SAFE MODE

PROCESS NO 2 --> FOR WINDOWS XP, VISTA, WINDOWS 7

START THE COMPUTER--> PRESS F8 BEFORE THE WINDOWS LOGO


FOR WINDOWS 8, WINDOWS 8.1, WINDOWS 10

PRESS SHIFT AT THE TIME OF CLICKING RESTART

GO TO TROUBLESHOOT --> ADVANCE OPTION -->STARTUP SETTINGS -->RESTART -->PRESS F4


TO UNINSTALL  A SOFTWARE

RUN-->APPWIZ.CPL-->SELECT THE LAST INSTALL SOFTWARE -->CLICK ON UNINSTALL





TO UNINSTALL A HARDWARE DRIVER

RUN --> DEVMGMT.MSC-->SELECT THE LAST INSTALLED HARDWARE -->RIGHT CLICK ON IT -->UNINSTALL DRIVER


TO UNINSTALL A DRIVER UPDATE

 RIGHT CLICK ON THE HARDWARE --> PROPERTIES -->DRIVER TAB -->ROLL BACK DRIVER


CAUSE NO 4

BOOT FROM WINDOWS INSTALLER DVD OR PEN DRIVE.   CLICK ON REPAIR YOUR COMPUTER OPTION UNDER  INSTALL NOW BUTTON.  TROUBLE SHOOT -->GO TO ADVANCE -->STARTUP REPAIR        --> SELECT THE TARGET OPERATING SYSTEM-->CONTINUE WINDOWS.


Sunday, June 6, 2021

SUMMARY OF INKJET PRINTER

INKJET PRINTERS

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THE MOST POPULAR TYPE OF PRINTER IN TODAYS MARKET IS INKJET PRINTER.  IT



USES A RESERVIOR OF INK, A PUMP AND A NOZZLE.  IT WORKS EFFECIENTLY AND T IS THE CHEAPEST PRINTER IN THE MARKET STARTING 1800 BUT THE PRINTER COST IS HIGHCOMPARING TO OTHERS TYPE OF PRINTER.


IT SPRAYS THE LIQUID INK ON TO A PAPER ACCORDING TO THE PATTERN OF PRINTED   DOCUMENTS.  IT SUPPORTS VERY HIGH DEFINATION OF THE DOCUMENT TYPES.


PARTS OF INKJET PRINTER:- INKJET PRINTER ARE SIMPLE DEVICE.  THEY CONTAINS VERY FEW PARTS.  THEY ARE INEXPENSIVE AND EASILY AVAILABLE IN THE MARKET.THE PARTS CAN BE DIVIDED INTO THE FOLLOWING CATEGORIES 


1) PRINT HEAD OF INK CARTRIDGE--> IT CONTAINS LIQUID INK AND TWO HUNDRED TINY NOZZLES TO SPRAY THE INK IN SMALL DROPLETS. MANY TIMES A PRINTER MAYCONTAIN A RESERVOIR OF INK.  MOST COMMON COLOURS ARE USED INTO SEPARATE CARTIDGE ONE FOR BLACK AND ANOTHER ONE FOR CYAN, MAGENTA AND YELLOW.  THERE ARE TWO METHODS OF SPRAYING THE INK.

THERMAL BUBBLE --> IT IS INVENTED BY HEWLET PACKARD AND IT USES A METAL PLATE AND A TUBE TO SUPPLY THE INK.  WHEN A PARTICULAR CHAMBER NEEDS TO SPRAY THE INK AN ELECTRIC SIGNAL IS SENT TO THE HEATING ELEMENT.  THE HEAT CAUSES THE INK TO FORM A BUBBLE AND PUSHED OUT OF THE PIN HOLE AND SPREAD ONTO THE PAPER.

PIEZO VIBRATOR--> IT IS INVENTED BY EPSON USES A MINIATURE DRUM OR PIEZO ELECTRIC ELEMENT THAT FLEXES WHEN CHARGE.  THE OUTWARD FLEX PUSHES THE INK FROM THE NOZZLE.  WHEN THE PRINTING IS DONE THE PRINT HEAD AND THE CARTRIDGE MOVES BACK TO THE MAINTENANCE SECTION.  IT CONTAINS A SMALL SECTION PUMP AND INK ABSORBING PAD.  THE SUCTION PUMP CLEANS THE NOZZLE AND EXPELLED INK IS ABSORBED BY THE PAD.


2) HEAD CARRIAGE BELT AND STEPPER MOTOR --> THE HEAD CARRIAGE CONTAINS THE INK CARTRIDGE WHICH MOVES BACK AND FORTH DURING PRINTING.   THE STEPPER MOTOR AND THE BELT MOVES THE HEAD CARRIAGE.  THIS ELECTRIC MOTOR CAN MOVE IN VERT SMALL INCREMENTS.  A BELT IS PLACED AROUND TWO SMALL WHEELS ATTACH TO THE PRINT HEAD CARRIAGE.  THIS BELT IS DRIVEN BY THE STEPPER MOTOR AND MOVES THE PRINT HEAD BACK AND FORTH.


3) PAPER FEED MECHANISM--> IT PICKS UP A PAPER FROM THE PAPER TRAY.  THE PICKUP ROLLER, WHICH ARE SEVERAL RUBBER ROLLER WITH A SLIGHTLY FLAT SPOT .  THEY RUB AGAINST THE PAPER AND FEED ONLY ONE PAPER INSIDE THE PRINTER AND REST OF THE PAPER PLACED IN THE PAPER TRAY. THE ROLLER IS MOVED BY BACKUP STEPPER MOTOR.   THE PAPER TRAY IS A SIMPLE PLASTIC TRAY WHICH HOLDS THE PAPER.   SOME PRINTERS HAS THE PAPER TRAY IN THE BACK SIDE.  THERE IS NO REAL REASON WHICH MANUFACTURES MAKES THE PAPER TRAY INFRONT OR BACK.  THE PAPER FEED SENSOR TELLS A PRINTER WHEN THERE IS NO PAGE IN THE PAPER TRAY OR A PAPER JAM OCCURS.   


4) CONTROL INTERFACE AND POWER CIRCUIT--> THE PRINTER CONTROL CIRCUITS ARE USSUALLY  OR A SMALL CIRCUIT BOARD REFFERED AS MOTHER BOARD THAT CONTAINS ALL CIRCUIT TO RUN STEPPER MOTOR PAPER FEED MOTOR AS THE PRINTER NEED.  IT ALSO MONITORS THE HEALTH OF A PRINTER AND REPORTS BACK TO THE PC .  THE INTERFACE CIRCUIT CONNECTS A PRINTER WITH  A COMPUTER USING SEVERALPARALLEL USB,  LANPORT.  IT RECIEVES THE DATA SIGNALS COMING FROM THE COMPUTER AND CONVERTS INTO TO SIGNALS WICH A PRINTER CAN UNDERSTAND.   THE FINAL PARTS OF THE POWER CIRCUIT IS THE POWER SUPPLY UNIT .   IT COVERTS 210 VAC INTO  12 AND 5 VOLT DC.  THIS IS ACCOMPLISHED BY A TRANSFORMER.


NOW LET US SEE HOW A PRINTER PRINTS A DATA OR IMAGE

1. YOU CLICK THE PRINT BUTTON ON A SOFTWARE TO PRINT A DOCUMENT.

2. THE SOFTWARE SENDS THE DATA TO A PRINTER DRIVER.

3. THE PRINTER DRIVER CONVERTS THE DATA INTO THE FORMAL THAT THE PRINTER CAN UNDERSTAND AND ALSO ENSURES THE PRINTER IS READY TO PRINT.

4. THE DRIVER SENDS THE DATA VIA A USB PARALLEL R NETWORK PORT TOWARDS HE PRINTER.

5. THE PRINTER STORES THE RECEIVED DATA IN A BUFFER.

6. THE PRINTER STARTS CLEANING CYCLE .  THE SUCTION PUMP PRINTS OUT DRY INK AND CLEARS THE NOZZLE.

7. THE PAPER FEED MOTOR INSERTS A PAPER INSIDE THE PRINTER.  IF THERE IS NO PAPER THE NOTIFICATION LED IS TURNED ON AND MESSAGE IS SENT TO THE COMPUTER.

8. ONCE THE PAPER IS IN RIGHT POSITION, THE STEPPER MOTOR AND BELT MOVES THE CARTRIDGE ACROSS THE PAGE LITTLE BY LITTLE. THE CARTRIDGE SPRAYS THE INK ON PAPER DEDICATED BY THE MOTHERBOARD AND MAKES THE PATTERN OF THE DOCUMENT.

9. AT THE END OF THE PASS ACROSS THE PAGE FEED MOTOR ADVANCES THE PAGE SMALL AMOUNT AND STEP 8 REPEATS.  THE PROCESS CONTINUES UNTIL THE PAGE IS FINISHED.

10. IF MORE PAGE IS NEEDED THE PROCESS START FROM STEP 7.

11. ONCE THE PRINTING IS COMPLETED AND THE LAST PAPER EJECTS.  THE PRINT HEAD IS PARKED AND THE PRINT PROCESS IS FINISHED.




THANK YOU FOR READING


Thursday, May 6, 2021

TROUBLE SHOOTING FOR NO DISPLAY IN PERSONAL COMPUTER.

 TROUBLESHOOTING FOR NO DISPLAY

FRIENDS TODAY I AM GOING TO TELL YOU ABOUT THE CORRECT STEPS TO BE TAKEN


IN ORDER TO REPAIR THE COMPUTER IF THERE IS NO DISPLAY.  MEANS THAT WHEN YOU START THE COMPUTER, THE CPU FAN AND SMPS FAN IS RUNNING ALL LED IS ON BUT THERE IS NO DISPLAY IN THE MONITOR.


STEP 1  START THE COMPUTER AFTER 30 SECONDS  PRESS NUMLOCK KEY COUPLE OF TIMES.  IF THE NUMLOCK LED IS GETTING ON AD OFF,  THEN THE PROBLEM IS WITH THE MONITOR.  IF THE NUMLOCK LED IS ON OR STEADY ON OR STEADY OFF THEN THE PROBLEM IS WITH THE CPU.


STEP2--> SUPPOSE THE PROBLEM IS WITH THE MONITOR 

1) CHECK THE AC WALL OUTLET (PLUG) AND POWER CODE WITH THE LINE TESTER OR MULTIMETER.  NOW CHECK THE POWER BUTTON IS ON AND THE BRIGHNESS EVEL OF THE MONITOR.  

2) IF THERE IS NO POWER  IN THE MONITOR  THEN THE POWER PANEL MIGHT BE FAULTY.  REPAIR THE MONITOR IF THE POWER LED IS ON, EJECT THE VGA CABLE  FROM THE CPU AND MESSAGE WILL APPEAR ON THE DISPLAY.    

3) IF IT DOES THEN THE VGA CABLE OR HDMI CABLE IS FAULTY.  REPLACE THE VGA AND HDMI CABLE.

4) IF THERE IS NO MESSAGE ON THE DISPLAY, THEN THE MONITOR IS FAULTY.  REPAIR OR REPLACE THE MONITOR.


STEP 3-->  SUPPOSE THE PROBLEM IS WITH CPU.  DURING TROUBLESHOOTING WITH THE CPU, IT IS RECOMMENDED TO USE A MOTHERBOARD, SPEAKER AND DEBUG CARD.  EJECT THE RAM CLEAN IT PROPERLY WITH THE RUBBER.  EJECT THE CMOS BATTERY CHECK THE VOLTAGE LEVEL.


CLEAR THE CMOS ATTACH THEM AGAINAND CHECK FOR DISPLAY.  IF STILL THE DISPLAY DOES NOT COME ATTACH A GOOD RAM.  STILL THE PROBLEM CONTIUOUS AND THE MOTHERBOARD SPEAKER IS GENERATING 3 BEEP CODES THEN RAM SLOT MIGHT BE FAULTY.


SUPPOSE RAM SECTION IS OK THEN YOU CAN USE THE DEBUG CARD TO FIND OUT  THE PROBLEM OR ATTACH  A VGA CARD  IF DISPLAY COMES THEN THE VGA PORT OF THE MOTHERBOARD IS FAULTY AN IF THE DISPLAY DOES NOT COME THEN THE VGA CONTROLLER MIGHT BHE FAULTY. IN BOTH CASES REPAIR THE MOTHERBOARD.



Tuesday, February 16, 2021

NETWORKING DEVICES A GENERAL SUMMARY

 NETWORKING DEVICES USED IN INTERNET CONNECTION: A GENERAL SUMMARY

NETWORK DEVICES, OR NETWORKING HARDWARE, ARE PHYSICAL DEVICES THAT ARE REQUIRED FOR COMMUNICATION AND INTERACTION BETWEEN HARDWARE ON A COMPUTER NETWORK.


LAYER 4 -> FIREWALL

LAYER 3 -> ROUTER

LAYER 2 -> BRIDGE, SWITCH

LAYER 1 ->LAN CARD, REPEATER, HUB, MODEM, ACCESS-POINT.


NETWORK INTERFACE CARD(NIC) A LAN CARD


IT IS A LAYER 1 DEVICE.  IT IS USED TO CONNECT A PC, LAPTOP, WORK STATION AND A SERVER TO A NETWORK.

A LAN CARD IS BUILT INTO A MOTHERBOARD BUT WE CAN PURCHASE ADDITIONAL LAN CARD ATTACH IT IN A PCI OR USB SLOT.  EVERY LAN CARD HAS ITS OWN MAC ADDRESS.


REPEATER





REPEATER IS A LAYER ONE DEVICE. IT WORKS LIKE N AMPLIFIER, BUT REMEMBER APLIFIER WORKS IN ANALOG SIGNAL WHERE REPEATER WORKS IN DIGITAL SIGNAL.  IT IS USED TO FIX THE PROBLEM OF ATTENUATION.


HUB



IT IS ALSO A LAYER1 DEVICE IT WORKS LIKE A REPEATER BUT REMEMBER REPEATER CANNOT BE A HUB.  A HUB CONTAIN 4, 6, 8, 12, 16 PORTS.  HUB REGENERATE AND INCOMMING SIGNAL AND FORWARDS IT BY ALL OFF ITS ACTIVE PORT.  THIS TYPE OF COMMUNICATION IS KNOWN AS BROADCAST.

HUB WORKS IN HALF DUPLEX MODE.  WHEN TWO DEVICES TRIES TO COMMUNICATE WITH EACH OTHER AT A SAME POINT OF TIME.  THEIR DATA GETS COLLIDED.


COLLISION DOMAIN


IN A HALF DUPLEX NETWORK WHEN TWO OR MORE THAN TWO COMPUTERS TRIES TO COMMUNICATE WITH EACH OTHER AT THE SAME POINT OF TIME THEIR DATA PACKETS GET COLLIDED.  IT IS CALLED COLISION DOMAIN.


WHEN A COLLISION OCCURS A JAM SIGNAL IS GENERATED AND ALL OF THE DEVICES INSIDE A NETWORK STOPS FORWARDING DATA.


BROADCAST DOMAIN

WHEN IN A NETWORK, A PC GENERATES A BROADCAST FRAME; ALL OF THE DEVICES INSIDE THT NETWORK GETS A COPY OF THE FRAME.   IT IS CALLED A BROADCAST DOMAIN.


A HUB NETWORK RESIDES INSIDE A SINGLE BROADCAST AND COLLISION DOMAIN.



CSMA – CD(CARIER SENSE MULTIPLE ACCESS COLLISION DETECTION)


IN A MULTI ACCESS NETWORK THE CARRIER SENSE MECHANISM DETECTS IF THE CHANNEL IS FREE OR NOT.  IT CHECKS FOR VOLTAGE LEVEL IN COPPER WIRE AND LIGHT IN FIBRE OPTICS.


THE COLLISION DETECTION MECHANISM DETECTS THE JAM SIGNAL AND STOPS FORWARDING DATA.  THEN A BACK OF ALGORITHM IS CALCULATED AND AGAIN THOSE COLIDDED DEVICES START SENDING THE DATA WITH LITTLE TIME GAP.



SWITCH



IT IS A LAYER 2 DEVICE.  IT WORKS WITH MAC ADDRESS.  IT IS A HARDWARE DEVICE.  IT IS ALSO KNOWN AS MULTIPORT BRIDGE.  A SWITCH CONTAINS  4, 8, 12, 16, 24, 48, 64 PORTS. EACH PORT WORKS AT FULL DUPLEX MODE.  EACH SIGNLE PORT OF A SWITCH IS IN SEPARATE COLLISION DOMAIN.


SWITCH CANNOT BREAK BROADCAST DOMAIN.  A SWITCHED NETWORK RESIDES INSIDE A SINGLE BROADCAST DOMAIN.  SWITCH HAS A PROCESSOR NAMED ASIC (APPLICATION SPECIFIC INTEGRATED CIRCUIT) WHICH LEARNS THE MAC ADDRESS OF ALL CONNECTED DEVICES AND STORES IN A TABLE CALLED CAM (CONTENT ADDRESSABLE MEMORY).


SWITCH IS OFF TWO TYPES (1) MANAGED SWITCH AND (2) UNMANAGED SWITCH.  (1)MANAGED SWITCH – THIS SWITCH CAN BE MANUALLY CONFIGURE (2) UNMANAGED SWITCH - THIS SWITCH CAN NOT BE CONFIGURED MANUALLY.


NOW I WILL SOMETHING ABOUT SWITCHING METHODS.


(1) CUT THROUGH SWITCHING

THIS TYPE OF SWITCH STARTS FORWARDING DATA FRAME IMMEDIATELY AFTER LEARNING DESTINATION MAC ADDRESS OF THAT FRAME.

IT IS A FASTEST SWITCHING METHOD.  THE PROBLEM WITH THE SWITCHING METHOD IS THAT IT CAN FORWARD CORRUPT FRAME AND RUNT FRAME (FRAME SIZE LESS THAN 64 BYTE).


(2)STORE AND FORWARD SWITCHING

THIS SWITCHING METHOD STORES THE ENTIRE FRAME INTO ITS BUFFER MEMORY.  THEN RUNS CRC(CYCLIC REDUNDANCY CHECK) TO VERIFY CORRUPTED DATA IF THE DATA IS GOOD THEN STARTS FORWARDING.

IT IS THE SLOWEST METHOD OF SWITCHING BUT NO CORRUPTED FRAME IS FORWARDING.  IF A BAD FRAME IS FOUND WITH BAD FCS(FRAME CHECK SEQUENCE).  IT WILL DROP THAT FRAME.


(3)FRAGMENT FREE SWITCHING

IT IS AN ADVANCED VERSION OF AS CUT THROUGH SWITCHING.  A SWITCH RUNNING IN FRAGMENT FREE MODE LEARNS THE FIRST 64 BYTE OF A FRAME, THEN STARTS FORWARDING THAT FRAME.  THIS METHOD DOESN’T ALLOW ANY RUNT FRAME TO BE FORWARDED.


FIREWALL


IT IS LAYER 4 DEVICE.  IT WORKS WITH ALL TYPES OF NETWORK ADDRESES (MAC, IP, PORT NUMBER).  IT IS A SECURITY APPLIANCE.   IT IS USED TO SECURE OUR NETWORK FROM UNATHOURIZED ACCESS, SUCH AS HACKING, NETWORK ATTACKS, VIRUSES AND WORMS.


FIREWALL IS OF TWO TYPES

1> SOFTWARE FIREWALL

2> HARDWARE FIREWALL


LET US SEE SOFTWARE FIREWALL

 IT IS A SOFTWARE BASE PROGRAM WHICH PROTECTS OUR PCS, LAPTROPS , SERVERS EG:- ANTIVIRUS FIREWALL, WINDOWS FIREWALL, COMODO FIREWALL, WINDOWS DEFENDER.


LET US SEE HARDWARE FIREWALL

IT IS A HARDWARE COMPONENT WHICH WORKS WITH SOFTWARE COMPONENT. IT CONTAINS VARIOUS SECURITY PROTOCOLS WHICH HELPS TO PROTECT A WHOLE NETWORK.

FOR EXAMPLE ->CISCO ASA, PIX, A5BIG IP, CHECK POINT, TALO ALTO


MODES OF FIREWALL


1.INTRUSION DETECTION SYSTEM

IT IS A PASSIVE PROTECTION WHICH DOESNOT BLOCK ANY MALICIOUS NETWORK ACTIVITY.  IT  HELPS TO MONITOR AND DETECT THOSE ACTIVITIES.


2.INTRUSION PREVENTION SYSTEM

IT IS A AN ACTIVE PROTECTION WHICH BLOCKS ANY MALICIOUS NETWORK ACTIVITY.



MODEM

MODEM MEANS MODULATION AND DEMODULATION.  THIS DEVICE CONVERTS ANALOG SIGNAL INTO DIGITAL SIGNAL AND VICE VERSA.IT IS USED WITH BROADBAND CONNECTION PROVIDED BY PLAIN OLD TELEPHONE SYSTEM (POTS) AND TELCO NETWORK. FOR EXAMPLE BSNL LANDLINE


MODEM IS OFF TWO TYPES:-

1> ADSL 2 WHICH PROVIDES WIRED NETWORK.

2> ADSL 2+ WHICH PROVIDED BOTH WIRED AND WIRELESS NETWORK.


ADSL – ASSYNCHRONOUS DIALUP SUBSCRIBER LINK


ACCESS POINT

IT IS A LAYER 1 DEVICE.  IT IS USED TO CREATE A WIRELESS LAN.  IT USES WIFI TECHNOLOGY .  IT NEVER MAKES COLLISION BUT WORKS INSIDE A SAME BROADCAST DOMAIN.  DATA ACCESS MECHANISM CSMA\CA  (CARRIER SENSE MULTI ACCESS WITH COLLISION AVOIDANCE).


THE COLLISION IS AVOIDED BY EXCHANGING CTS AND RTS MESSAGE.  ACCESS POINT WITH LAYER 3 ENGINE CAN FORWARD I TRAFFIC FROM ONE NETOWK TO ANOTHER THEN IT IS CALLED A WIFI ROUTER.


THE WIFI STANARDS COMES UNDER IEEE (INSTITUTE OF ELECRICAL AND ELECTRONICS ENGINEERS) 802 PROJECT.  WIFI COMES UNDER 802.11 STAMDARD.  IT HAS 5 SUB STANDARD.802.11 A,  802.11B, 802.11G, 80211N, 802.11AC.


ROUTER



IT ISS A LAYER 3 DEVICE.  IT IS USED TO CONNECT MULTIPLE NETWORKS.  IT WORKS WITH IP ADDRESS.  A ROUTER FORWARDS DATA PACKETS FROM ONE NETWORK TO ANOTHER ACCORDING TO THE DESTINATION IP OF THE DATA PACKET.


IF A DESTINATION IP NETWORKIS UNKNOWN TO THE ROUTER IT WILL DROP THAT PACKET.  TO LEARN ABOUT THIS NETWORK INFORMATION VARIOUS ROUTING PROTOCOLS ARE IMPLEMENTED IN A ROUTER.


ROUTER STORES THE UNKNOWN NETWORK INFOMRATION IN A TABLE KNOWN AS ROUTING INFORMATION BASE(RIB) OR ROUTING TABLE.  ROUTER WORKS AT FULL DUPLEX MODE.  IT NEVER BROADCAST .  EACH SINGLE PORT OF A ROUTER IS IN SEPERATEDE BROADCAST DOMAIN AND COLLISION DOMAIN.


Monday, July 27, 2020

CHIPSETS OF COMPUTERS.


A CHIPSET IS A COLLECTION OF CHIP OR CIRCUITS THAT PERFORM INTERFACE AND PERIPHERAL FUNCTION FOR THE PROCESSOR.  THIS COLLECTION OF CHIPS IS USUALLY THE CIRCUITS THAT PROVIDES INTERFACES FOR MEMORY EXPANSION CARDS AND ONBOARD PERIPHERALS AND GENERALLY DICTATES HOW A MOTHERBOARD WILL COMMUNICATE WITH THE INSTALLED PERIPHERALS.
CHIPSET ARE USUALLY GIVEN A NAME AND MODEL NUMBER BY THE ORIGINAL MANUFACTURER AND MODEL ALSO TELL YOU THAT YOUR PARTICULAR CHIPSET HAVE A CERTAIN SET OF FEATURES EG TYPE OF RAM SUPPORTED TYPE AND BRAND OF ONBOARD AND SO ON.

CHIPSETS CAN BE MADE UP ONE OR MORE INTEGRATED CIRCUIT CHIPS.  INTEL BASED MOTHER BOARDS TYPICALLY USE TWO CHIPS.  THE FUNCTION OF CHIPSETS CAN BE DIVIDED INTO TWO MAJOR FUNCTIONAL GROUPS CALLED NORTH BRIDGE AND SOUTH BRIDGE.

NOW I AM GOING TO SHOW YOU SOME OF THE BASIC CHIPSET IN COMPUTERS AND WIDELY USED CHIPSETS USED IN MODERN COMPUTERS .  THEIR NAMES AS 1) NORTH BRIDGE 2) SOUTH BRIDGE

SO LET US BEGIN IN OUR LITTLE JOURNEY.

NORTH BRIDGE

THE NORTH BRIDGE SUBSETS OF MOTHERBOARD CHIPSET, IS THE SET OF CIRCUITS OR CHIPS THAT PERFORM ONE VERY IMPORTANT FUNCTION: MANAGEMENT OF HIGH SPEED PERIPHERAL COMMUNICATIONS.

  THE NORTH BRIDGE IS RESPONSIBLE PRIMARILY FOR COMMUNICATIONS WITH INTEGRATED VIDEO USING AGP AND PCIE AND PROCESSOR TO MEMORY COMMUNICATIONS.  THEREFORE IT CAN BE SAID THAT MUCH OF THE TRRUE PERFORMANCE OF A PC RELIES ON THE SPECIFICATION OF THE NORTH BRIDGE COMPONENT AND ITS COMMUNICATION CAPABILITY WITH THE PERIPHERALS IT CONTROLS.

THE COMMUNICATIONS BETWEEN THE CPU AND MEMORY OCCUR OVER THE FRONT SIDE BUS(FSB). WHICH IS JUST A SET OF SIGNAL PATHWAYS CONNECTING THE CPU AND THE SYSTEM MEMORY .  THE CLOCK SIGNAL THAT DRIVES HE FSB IS USED TO DRIVE COMMUNICATION BY CERTAIN OTHER DEVICES, SUCH AS AGP AND PCIE SLOTS.

THE NORTH BRIDGE IS DIRECTLY CONNECTED TO THE SOUTH BRIDGE.  IT CONTROLS THE SOUTH BRIDGE AND HELPS TO MANAGE THE COMMUNICATION BETWEEN THE SWOUTH BRIDGE AND THE REST OF THE COMPUTER.

SOUTH BRIDGE

THE SOUTH BRIDGE IS SUBSET OF THE CHIPSET IS RESPONISIBLE FOR PROVIDING SUPPORT TO THE ONBOARDS SLOWER PERIPHERALS SUCH AS PS2, PARALLEL PORTS, SERIAL PORTS, PATA, SATA ETC. MANAGING THE COMMUNICATION WITH THE REST OF THE COPUTER AND THE RESOURCS GIVEN TO THEM.

THESE COMPONENTS DO NOT NEED KEEP UP WITH THE EXTERNAL CLOCK OF THE CPU AND DO NOT REPRESENTS A BOTTLENECK IN THE OVER ALL PERFORMANCE .  THE SOUTH BRIDGE IS ALSO RESPONSIBLE FOR MANAGING COMMUNICATIONS WITH THE SLOWER EXPANSION BUSES LIKE PCI SLOT ETC.

Wednesday, July 1, 2020

ARITHMETIC CALCULATION IN COMPUTERS


ARITHMETIC OPERATION AND CONVERSION DONE BY COMPUTER
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As we have seen in previous post that arithmetic computation is an important thing in calculation, if a person doesn’t know arithmetic computations,  he will be doomed to be in trouble during calculations that happens  in everyday life.  So it is necessary to learn arithmetic computation.  So in this post I am going to take one step further.  I am going to write about octal and hexadecimal numbers.

Now let us discuss some arithmetic conversion.  Let us see what is octal and hexadecimal numbers used by digital computer.

The conversion from and to binary, octal and hexadecimal plays an important part in digital computers.  Since 23 = 8 and 24 = 16 each octal digit corresponds to three binary digits and each four binary digit corresponds to one hexadecimal digit. 

The conversion of from binary to octal is easily accomplished by partitioning the binary into group of three digit each, starting from binary point and preceding to the left or to the right.

The corresponding octal digit is then assigned to each group.  The following  example illustrates the procedure.

 10 110 001 101 011 .  111 100 000 110   = (26153.406)2
  2     6     1     5      3        7      4       0     6

Conversion from binary to hexadecimal is similar,  except that the binary number is divided into group of four digits:
 

10 1100 0110 1011 .  1111 0010    =  (2C6B.F2)16
  2     C       6       B            F        2


The corresponding hexadecimal (or octal) digit for each group of binary digits is easily remembered after studying the values. 

Conversion from octal or hexadecimal to binary is done by procedure reverse to the above.  Each octal digit  is converted to three bit binary equivalent .  Similarly, each hexadecimal digit  is converted to its four-digit binary equivalent. 

Binary numbers are difficult to work with because they require three or four times as many digits as their decimal equivalent .  For example, the binary number 111111111111 is equivalent to decimal number  4095.  However, digital computers use binary numbers and its sometimes necessary for human user to communicate directly to with the machine by means of binary numbers.


One scheme that retains binary  system  in the computer but reduces the number of digits human must consider utilizes the relationship between  binary number system and octal and hexadecimal system.  By this method, the human thinks of the number of octal and hexadecimal  numbers  and performs required conversion by inspection when direct communication by the machine is necessary.  Thus the binary numbers 111111111111 is 12 digit and is expressed in octal as 7777 (four digits) and while it is expressed in hexadecimal as FFF (3 digits).

During communication between people (about binary numbers in the computer), the octal or hexadecimal representation is more desirable because it can be represented in third or quarter of number of digits required for equivalent binary number.

When the human communicates with the machine (through console switches or indicator lights or by means of programs written in machine language),  the conversion from octal or hexadecimal  to binary and vice versa is done by inspection by the human user.


                                                                                   Thank you for reading

Sunday, June 14, 2020

MONITORS: A COMPUTER PART


Folks today i am going to say something about an output device called monitor.  As maximum people know about monitors so i am going to write few things about monitor much of the information you know but i am going to say some few words hence please be with me.

Monitor is a primary output device.  It displays all current process application and data i.e. Running inside a computer system.  A standard monitor uses an analog vga interface, which plugs into a tp15 vga connector to a mother board.  There are two types of monitor technology available to the market.

CATHODE RAY TUBE (CRT MONITOR)

This monitor is fading in popularity but still in widespread use with older computer systems.  It is analog standard monitor a crt uses a picture tube that was used in older tube based tv sets.

  The narrow end of the picture tube contains an electron gun it emits 3 electron beams one each for red, green and blue light.  The front end of the picture tube is coated with phosphorous.  When the elecron hit the phosphorous coating it starts to glow.

Just before the phosphorous coating a metal plate called a shadow mask uses one of the three technologies phosphor triad, an aperture grill, a slotted mask.
Crt monitors are bulky, takes more desk space, consumes more power and emits more heat.  Crt monitors were available from 15 inch to 19 inch size.  It uses vga connector to attach with a cpu.


 LCD AND LED SCREENS

The most popular monitor in todays market is led monitor surpassed lcd monitors.  Because it gives better color quality, wide viewing angle and consumes less power.  It uses liquid crystal cells to polarize the light.  Lcd uses fluorescent lamp and led monitor uses led lamp for back lighting.  This display uses an array of transistors to control each cell variation are the colour bit response time and the refresh rate. 
This monitor comes with two types of transistor technology (1) passive matrix (2) active matrix.
Now i will discuss about passive matrix so lets be.
PASSIVE MATRIX
A passive matrix display does not have a dedicated transistor for each pixel or sub pixel, bit instead of a matrix of conductive traces.  In simplified terms for a single pixel, when the display is instructed  to change the crystal line alignment for a particular pixel and sends a signal  accross the x and y coordinate traces that intersect at that pixel, thus turning it on.  A 1366 * 768 resolution monitor contains 1366 transistors at that horizontal edge and 768 in vertical edge. The viewing uncle is a most unconsiderable issue of a passive matrix display.  The picture quality is muddy because the conductive traces sometimes affects the neighbouring pixels of a target pixel. The one advantage of passive matrix is it consumes less power comparing to active matrix display.

DUAL SCAN DISPLAY
A dual scan is a  variation of the passive metric display.  The classic passive matrix screen is split in half to implement a dual scan display.  Each half of the display is refreshed separably leading to increased quality.  Although dual scan improves the quality of refresh rate but it cannot rival the quality produced by active matrix.

ACTIVE MATRIX

This screen is made of several independent lcd or led pixels.   A transistor at each pixel location, when switched among various levels activates two opposing electrodes that align the pixels crystal two opposing electrodes that align the pixels crystals and alter the passage of light at that location two produce millions of colour shades. 

This type of display is very crisp and easy to look at from any angle.  It doesn’t require a scan refreshing to maintain an image.  Because transistors conduct current only in one direction and the pixels acts like a capacitor by holding its charge until it is refreshed.

 Higher refresh rate results in better video a gaining performance not for still image.  The major disadvantage of active matrix screen but it requires more power to operate all transistors.  Even if the backlight is turned of the screen can still consume power at an alarming rate.  Another problem with active matrix is light bleed.


Sunday, June 7, 2020

PROCESSOR AND HYPER THREADING A SHORT SUMMARY


PROCESSOR AND HYPERTHREADING
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Friends in the last post i tried to say something about computer science and mathematics relationship.  Now i am going to say something about processor and hyperthreading.  So let’s get started.

The Physical Component By Which A Computer Is Made Which We Can See, Touch And Feel Is Called Computer Hardware Example Ram, Motherboard.
·         INPUT DEVICE  : These hardware are used to input any data, instruction on command insidea computer device.  example keyboard mo9use scanner microphone, webcam etc
·         OUTPUT DEVICE:  these hardware are used to get any output from a computer system.  example: monitor, printer, speaker.
·         CENTRAL PROCESSIG UNIT (CPU): This Device Proceses All Instruction Given By A User, And It Also Other Haqrdwqaar Peripherals Example  :Microprocessor
·         MOTHERBOARD: It is the main electric circuit board which is made by a pcb(printed circuit board).  It hods all hardware components and provide interface to those component by which they can communicate with each other.
·         MEMORY: These hardware are used to storedata temporarily on permanent.  these are two types
o   PRIMARY MEMORY:- These Memories Are Direclty Accessed By A System Cpuit Does Not Need Any Third Controller To Occur This Memory Example :- Ram , Rom
o   SECONDARY MEMORY:- A cpu needs additional computer to access this memory.  They are basically storage device. Example:- hard disc, cd-dvd, pendrive, sd cards etc.
·         POWER SUPPLY UNIT (PSU):-  This Unit Convert Alternating Current To Direct Current And Provides A Regulated Popwer Supply To All Hardware Peripherals Example :- Switch Mode Power Supply.

All the above is written by me is to acknowledge you about the primary technology of the computer peripherals.  Now i am going to tell you about the cpu and its secondary technology.

SINGLE CORE VS MULTI CORE
A cpu contains single or multiple processsing chips.  These chips are made by silicon.  A chip takes three hundrede steps to be manufacture. A processing containing single chip is known as single core processor .

In dual core it contains two chips that means it have two processor in a package.  In quadcore it contains four chip and show on more numbers o chips gives better performance and reduces processing delay.



HYPERTHREADING
It is a feature of certain intel processor that makes one physical cpu and appears two logical cpu.  It uses additional registers two overlap two instruction which achieve an appropriate thirty percent gain in performance.

Multi threaded applications take advantage of hyperthreading .  But it cannot rival with the performace achieved by a true dual core processor it was introduced by intelwiht their prentium four processor and reffered as “ht” technology.

This technology is supported by syistem software to take advantage.  Most of the todays operating system such as windows and linux aree capable of dividing their workload among multiple processors. This is called symmetric multi processing (smp).


Friday, March 13, 2020

IS DIGITAL COMPUTERS ARE VALUABLE?


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DIGITAL COMPUTERS

Today computers are used extensively in every day life.  It is used in basic as well as industrial, scientific and commercial purposes.  Our space program would not have been well developed without the real time monitoring of the machine of the spacecraft which was going to land on moon or any other planet of the scheduled program or launching of satellites on the orbit of earth. This is the scientific purpose i told you about while it has commercial purposes.  Like automatic data processing which the business enterprise uses.

It has many works in educational purposes for example multiple choice question answers can be checked without any error and then the results can be printed out automatically with the help of the printer which is connected to the digital computer.

  Digital computer are also used in air traffic control to control the aviation industry to help them control the planes by sending them data about the distance between the planes and the ground as well as about other planes coming their way.  Digital computers are heavily used because of its simplicity and generality. 

 Generality because it takes data as input for manipulation of input to get a desired output.  In simple words it can follow a sequence of instruction called a program that operates on a given data, then the programmer can change the programs according to his need.

The general purpose digital computers is best known example of a digital system.  Other examples include telephone switching exchanges, digital voltmeter, frequency counters and calculating machines.  I am telling about this machines because these machines take about inputs and give desired outputs. 

 These inputs can be said as discrete elements because most generally there are electrical signals, electrical impulses, frequency counters, decimal digits letters of an alphabet.  Characteristics of digital system is manipulation of discrete elements of information. 

 Such alphabet, arithmetic operations punctuation marks or any other set of meaningful symbols.  The juxtaposition of discrete elements of information represents a quantity of information.  For example the word dog  is formed by letters d , o, and g.  The letter 237 form the number and etc. 

 Thus a sequence of the letter form a language that conveys information.  Early the computer were used only for calculation.  From this case the discrete element of information used are the digits.  From this came the word digital computers.


Thursday, March 12, 2020

LOGIC OF COMPUTERS


LOGIC OF COMPUTER IN PAPER AS WELL AS PRACTICAL USE


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We always use logic in every day matters, so do the machines.  But we were taught by experiences we count and the people we trust and these things matters most because it will help in dark times.  But to make the machine understand the logic is very hefty work. But this is certainly not impossible.  In order to understand logic we use integrated circuits.  But to do this we need to design the integrated circuits on paper.  This requires certain rules of algebra.  This I am going talk about the rule of an algebra called the duality principal.

It states that every algebraic expression deducible from the postulates of Boolean algebra remains valid if the operators and identity elements are interchanged.  In a two value Boolean algebra, the identity elements and the elements of the set B are same 1 and 0.  The duality principal has many applications.  If the dual of an algebraic expression is desired, we simply interchange OR and AND operators and replace 1’s by 0’s and 0’s and 1’s.

I am going to show some of the rules below which some are Boolean algebra theorems and some are postulates, there Is some problem because the notation contains some . which is sometimes misunderstood.  Now the theorems and postulates listed are the most basic relationships in Boolean algebra.  The theorems, like the postulates are listed in pairs each relation is dual of the one paired it.  The postulates are basic axioms of the algebraic and need no proof.  The theorems must be proven from the postulates.  The proof of the theorem with one variable is presented below.  At the right is listed the number of postulates which justifies each step of the proof.

Postulate 2
(a) x + 0 = x
(b) x.1 = x
Postulate 5
(a) x+ x’=1
(b) x*x’ = 0
Theorem 1
(a) x + x=x
(b)x*x=x
Theorem 2
(a)x + 1= 1
(b)x*0=0
Theorem 3, involution
(a)(x’)’ =x

Postulate 3 commutative
(a) x + y = y + x
xy = yx
Theorem 4 associative
(a) x + (y + z) = (x + y) + z
(b) x(yz) = (xy)z
Postulate 4 Distributive
(a)x(y+z) = xy +xz
(b) x + yz=(x + y)(x + z)
Theorem 5, DeMorgan
(a)(x+y)’ = x’y’
(b) (xy) = x’ + y’
Theorem 6, Absorption
(a) x + xy = x
(b) x(x+y) = x





RANDOM ACCESS MEMORY


ALL ABOUT RAM
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RAM (random access memory) is a place in computing device where the operating system, application programs and data in current uses are kept .  So they can be quickly reached by the device processor. Ram is much faster to read from and write to than other kinds of storage in a computer, such as hard disk drive (hdd) solid turned off.  Ram loses its data when the computer is turned on again,  the operating system and other files once again loaded into ram again.

Types of ram
Ram can be classified into two types
1.       Static ram   
2.       Dynamic ram

Static ram
Static ram is a random access memory (ram) that retain its memory as long as power is being supplied or any new new input enters.  Unlike dynamic ram, which stores bits in cellsconsisting of a capacitor and a transistor is in a latch circuit (flip flop).  Sram does not have to periodically refreshed.  Static ram provides faster access to data and is more expensive than dram.  Sram is used for a computers cachememory and as part of the ram digital to analog converter on a video card.

Dynamic ram
Dynamic ram is a type of memory i.e. Typically used for data or  program code  that a computer processor need to function dram is comon type of random access memory (ram) used in personal computer workstation and servers.  Random access allows the pc processor toaccess any part of the memory directly rather than having to proceed sequencially from a starting place.  Ram is located close to a computers processor and enables faster access to data than the storage media such as hard disk drives and solid state drives.

Types of dram

SD RAM
Sdram (synchronous dram ) is a generic name for various kinds of dynamic random access memory  (dram) that are synchronized with clock speed that the microprocessor is optimized for this temds to increase the number of instrction that the processor can perform in a given type.  The speed of sd ram israted in mega hertz rather than in nanosecond (ns).   This makes it easier to compare the bus speed and the ram chip speed to nano second by dividing the chip speed into 1 billion ns which is for speed for example an 83 mhz ram would be equavilent to 12 ns.

DDR RAM
Ddr ram staqnds for double data rate random access memory. Double data rate that it can getch data on both the up and down cycles of the clock,  unlike the previous bersion of ram which only fetched on ome clock edge.

 the original ddr ram was a avery simple  exactlylike the old sd ram bvut with the speed at which it could transfer double by transfering on both clock edges.  Ddr2 ram added a 2x multiplicater with 4x clock multiplier, thus running at 4 times the memory transfer rate for the same bus speed as the original ddr ram additionally ddr2 os capable of running at a lower voltage than ddr2.

  finding details about ddr4 that can succintly describe the difference isnt a particular simple task.  But what i can find so far is that ddr4 runs on a lower voltage than ddr3 is capable of running at a higher clock speed tyupically ddr3 is 1600 mhz for desktop 1333 for laptop while typically ddr4 may be 1866 for laptop and 21323 for desktop and can more easily come in much more dense apckages ddr3 maxes out at 16 gb dimm slot, ddr4 may  end out maxing out at 128 gb/ dimm slot).


Features
Ddr1
Ddr2
Ddr3
Ddr4
Max front side bus speed
400 mhz
800 mhz
2133 mhz
3200 mhz
Pins
184
240
240
288
Voltage
2.5 v
18.v
1.5 v
1.2 v

  RD RAM
Rd ram (rambus dynamic random accesss memory) is a memory subsystem that promises that to transer upto 1.6 billion bytes per second.  The subsystem consist of the random access memory (ram) the ram controller and the bus connection ram to the microprocessor and divices in the computer that used it.


DIRECT RAMBUS
DR DRAM technology  developed and cleansed by the rambus corporation is the latest version and is expected to help accelerate the growth of visually intensive interfaces such as 3-d interactive games and streaming multimedia.

  Rambus is intended to replace the current main memory technology at dynamic random access memory dram much faster data transfer rates from attached devices such as video cams using firewire and the accelerated graphics memory make it important to reduce the bottle neck in getting data into its computer staging it in ram and moving it through the microprocessor to the display or other output devices.

Direct Rambus (DRDRAM) provides a two byte (16 bit bus rather than DRAM 8bit bus.  At a RAM speed of 800 megahertz (800 million cycles per second), the peak data transfer rate is 16 billion bytes per second.  Direct RAMBUS uses pipelining to move data from RAM to cache memory levels the are closer to the microprocessor or display.

Upto 8 operation may be underway at the same time.  RAMBUS is designed to fit existing motherboard standards.  The eight components that are inserted into motherboard connections are called RAMBUS inline Memory Module (RIMMS). 

They can replace conventional dual in line memory module .  An Alternating to DRDRAM is syncklink DRAM.

HOW TO CONFIGURE VIRTUAL MEMORY IN WINDOWS OPERATING SYSTEM?

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