WHAT IS PROCESSOR ? WHAT IS MEMORY ?
A UNIT OF COMPUTER THAT INTER PRE INSTRUCTION AND EXCLUDES THEM AND PROCESSOR MEANS PERFORMING A SERIES OF ACTION OR OPERATION ON DATA TO CONVERT THEM INTO INFORMATION .
TYPES OF PROCESSOR
- CISC ( COMPLEX INSTRUCTION SET COMPUTER)
- RISC (REDUCED INSTRUCTION SET COMPUTER)
- EPIC ( EXPLICITLY PARALLEL INSTRUCTION COMPUTING)
1 CISC :- AN ARCHITECTURE OF CPU WITH LARGE INSTRUCTION SET, VARIABLE- LENGTH INSTRUCTION AND A VARIETY OF ADDRESSING MODES.
2 RISC :- AN ARCHITECTURE OF CPU WITH SMALL INSTRUCTION SET , FIXED LENGTH INSTRUCTING AND REDUCED REFERENCE TO MEMORY TO RETRIEVE OPERANDS.
3EPIC :- A TECHNOLOGY THAT IS FIRST EMERGING AS THE TECHNOLOGY FOR NEXT GENERATION PROCESSORS.
FEATURES OF PROCESSOR
THREE KEY FEATURES USED IN THAT TECHNOLOGY FOR IMPROVING PROCESSOR PERFORMANCE AND EXPLICIT PARALLELISM PREDICATION ,AND SPECIFICATION
PROCESSOR SPEED
PROCESSOR FETCHES DUDES AND EXECUTES INFORMATIONAL PROPER INTERVALS WITH INTERVAL TIMED ,BY A SPECIFIC NUMBER OF CLOCK CYCLES ONE CYCLES IS THE TIME IT TAKES PERFORM ONE OPERATION SUCH AS MOVING A BYTE OF DATA FROM ONE MEMORY LOCATION TO ANOTHER.
WE MEASURE THE PROCESSOR SPEED FOR MICRO COMPUTER IN MH2( MEGA HEART 2) AND GH2 ( GIGA HEART 2)
IN MINI COMPUTER AND MAIN FRAME COMPUTER IN MIPS (MILLION OS INSTRUCTIONS PER SECOND) AND SUPER COMPUTER IN MFLOPS( MILLIONS OF FLOATING POINT OPERATIONS PER SECOND).
CPU ( CENTRAL PROCESSING UNIT)
THE CONTROL UNIT AND ARITHMETIC LOGIC UNIT OF A COMPUTER SYSTEM ARE JOINLY KNOWN AS CPU , IT IS THE MAIN BRAIN OF COMPUTER SYSTEM IN WHICH ALL THE CALCULATIONS AND COMPRESSIONS PERFORMED BY A COMPUTER ARE CARRIED OUT ,THE CPU ALSO RESPONSIBLE FOR ACTIVATING AND CONTROLLING OPERATION OF OTHER UNITS OF A COMPUTER SYSTEM.
SOME COMPONENTS OF CPU
- CU (CONTROL UNIT )
- ALU (ARITHMETIC AND LOGIC UNIT
- INSTRUCTION SET AND REGISTER
- MEMORY UNIT ( IT KNOWN AS STROGE UNIT)
- OPERATIONAL UNIT
CU (CONTROL UNIT):- CU IS THE MOST IMPORTANT PART OF THE CPU AS IT CONTROL AND CO-ORDINATION THE ACTIVITIES OF ALL OTHER UNIT .THE CU ACTS AS A CENTRAL NERVOUS SYSTEM OF MANAGES AND CO-ORDINATES THE CENTER COMPUTER SYSTEM.
ALU ( ARITHMETIC & LOGIC UNIT) :- THE FUNCTION OF AN ALU IS TO PERFORM ARETHMETIC AND LOGICAL OPERATION , SUCH AS ADDITION SUBTRACTION ,MULTIPLICATION AND DIVISION ALONG WITH LOGICAL OPERATIONS LIKE AND ,OR ,NOT ,INTERMENT DECREMENT,COMPARISON OPERATIONS.
INSTRUCTION SET AND REGISTER
INSTRUCTION MEANS COMMAND OR ORDER GIVEN TO THE COMPUTER ,IT NORMALLY CONSISTS OF A CODE TO INDICATE THE OPERATION TO BE PERFORMED AND INSRUCTION SET MEAN A GROUP OF EVERY CPU HAS BUILT IN ABLITY TO EXECUTE A SET OF MACHINE INSTRUCTIONS CALLED ITS INSTRUCTION SET . ALL CPU IS NOT SAME INSTRUCTION SET ,DIFFERENT CPU HAVE DIFFERENT INSTRUCTION SET.
REGISTER AS A COMPUTER CPU INTERPRETS AND EXECUTES INSTRUCTION , THERE IS MOVEMENT OF INSTRUCTION BETWEEN THE VARIOUS UNITS OF A COMPUTER .TO HANDLE THIS PROCESS ,SATISFACTORY AND TO SPEED UP RATE OF INFORMATION TRANSFER .THE CPU USES A MEMBER OF SPEACIAL MEMORY UNITS CALLED REGISTER.
REGISTER ARE SMALL AND HIGH SPEED STORAGE UNITS THAT HOLD DATA TEMPARARITY ,WHEN THERE IS AN INTERPRETATION AND EXECUTIONS OF INSTRUCTION BY CPU.
THE NUMBER OF REGISTER VARIOUS FROM COMPUTER TO COMPUTER ,
THERE ARE SOME COMMON REGISTERS TO ALL THE COMPUTERS.
- MAR(MEMORY ADDRESS REGISTER):-IT HOLDS THE ADDRESS OF THE ACTIVE MEMORY LOCATIONS.
- MBR(MEMORY BUFFER REGISTER):- IT HOLDS THE CONTENTS OF THE ACCESSED (READ/WRITE ) MEMORY WORD ON IT ,WAY TO AND FROM MEMORY .
- PROGRAM CONTROL:- ITS HOLD THE ADDRESS OF THE NEXT INSTRUCTON FOR EXECUTION.
- A(ACCUMULATOR):- IT HOLD THE DATA OR WHICH THE SYSTEM HAS TO OPERATE INTER MEDIATE RESULT AND RESULTS OF OPERATIONS PERFORMED.
- I(INSTRUCTION REGISTER):- IT HOLDS THE CURRENT INSTRUCTION UNDER EXECUTION (HOLDS AN INSTRUCTION )WHILE IT IS BEING EXECUTED.
- I/O(INPUT/OUTPUT):- THE SYSTEM USES I/O REGISTER TO COMMUNICATE WITH INPUT AND OUTPUT DEVICE.
MEMORY UNIT(STORAGE UNIT)
MEMORY CHIPS| VOLATILE | NON VOLATILE| MANUFACTURE PROGRAM ROM | USER PROGRAMMED |
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THIS UNIT IS DATA AND INSTRUCTIONS ENTERED INTO A COMPUTER SYSTEM THROUGH INPUT UNITS HAVE TO STORED INSIDE THE COMPUTER BEFOR ACTUAL PROCESSING STORAGE . IN SHORT A STORAGE UNIT HOLDS
- THE DATA / INSTRUCTION REQUIRED FOR PROCESSING
- INTER MEDIATE RESULT OF PROCESSING
- FINAL RESULT OF PROCESSING ,BEFORE THE SYSTEM RELEASES THEM TO AN OUTPUT UNIT.
TYPE OF MEMORY
STORAGE DEVICE ARE TWO TYPES
- PRIMARY MEMORY OR MAIN MEMORY
- SECONDARY STORAGE OR AUXILIARY MEMORY
PRIMARY MEMORY:- MAIN MEMORY OF A COMPUTER SYSTEM CONSISTS OF SEVERAL SMALL STORAGE AREAS CALLED LOCATIONS OR CELLS.EACH OF THESE LOCATIONS CAN STORE IS FIXED NUMBER OF BITS CALLED WORD LENGTH OF THE MEMORY. (MORE BITS MEANS MORE POWER ,MORE SPEED)
TYPE OF MAIN MEMORY
MEMORY CHIPS ARE CLASSIFIED MAINLY BASED ON THUS CAPABILITY TO RETAIN STORED DATA ,WHEN POWER IS TURNED OFF OR INTERRUPTED.
- RAM( RANDOM ACCESS MEMORY):- THIS IS APART OF STOREGE WHERE DATA AND PROGRAM INSTRUCTION AND HOLD TEMPORARY ,WHILE BEING MANIPULATED OR EXECUTED. IT IS CALLED RAM BECAUSE ANY OF THE LOCATIONS ON THE CHIP CAN BE STORE AND RETRIEVE DATA AND INSTRUCTIONS.RAM IS A VOLATILE MEMORY
RAM IS TWO TYPE
- DYNAMIC RAM (DRAM)
- STATIC RAM(SRAM)
DYNAMIC RAM(DRAM):- DRAM USES ON EXTERNAL CIRCUITRY TO PERIODICALLY REGENERATE OR REFRESH STORAGE CHANGE TO RETAIN THE STORED DATA .
SRAM (STATIC RAM ):-IT DOES NOT NEED ANY SPECIAL REGENERATE CIRCUITY RETAIN THE STORED DATA .SRAM CHIPS ARE MORE COMPLICATE AND TAKE UP MORE SPACE THAN DYNAMIC RAM CHIPS BECAUSE THEY REQUIRED MORE TRANSISTORS AND OTHER DEVICES TO STORE A BIT OF DATA.
- ROM(READ ONLY MEMORY ):IN ROM THE STORED DATA RETAIN AFTER THE POWER SUPPLY OFF, IT IS A NON VOLATILE , ROM ARE ALSO UNKNOWN AS FIELD STORES PERMANENT STORES OR DEAD STORES ,ROM CHIPS CONTAIN MICRO-PROGRAM CONTROL INSTRUCTION OR SYSTEM BOOT PROGRAM THAT CAUSE THE MACHINE TO PERFORM OPERATION SUCH AS STARTING THE COMPUTER OR INSTRUCTIONS TO THE ENTIRE OPERATING SYSTEM.
- PROM (PROGRAMMABLE READ ONLY MEMORY):- PROM IS A PROGRAMMABLE ROM ,THERE ARE TWO TYPE OF ROM - MANUFACTURE -PROGRAMMABLE AND USER PROGRAMMED. BOTH THE USER CAN STORE THEIR PROGRAM IN ONE SHOT ,AFTER THE ONE USE IT BECOMES ROM, IT CAN NOT BE PROGRAMMED IN THE USE.
- EPROM( ERASABLE PROGRAMMABLE ROM):- ONCE INFORMATION IS STORAGE IN A ROM OR PROM CHIP A USER CAN NOT AFTER IT ,ERASABLE PROGRAMMABLE READ ONLY MEMORY CHIP OVER COME ,THIS PROBLEM BY ALLOWING USERS TO REPROGRAM IT EASILY TO STORE NEW INFORMATION EPROM CHIPS ARE OF TWO TYPES
- ULTRA VIOLET EPROM :- IN UVEPROM ,WHICH REQUIRES EXPOSING THE CHIP FOR SOME TIME TO ULTRA VIOLET LIGHT FOR ERASING INFORMATION STORED IN IT.
- ELECTRICALLY EPROM :-WHICH REQUIRES USE OF HIGH VOLTAGE ELECTRIC PULSE FOR ERASING INFORMATION STORED IN IT EEPROM IS ALSO KNOWN AS (FLASH MEMORY ) BECAUSE OF THE CASE WITH WHICH A USE CAN AFTER PROGRAMS STORED IN IT EXPLAIN DIVE MP3
CACHE MEMORY
CACHE MEMORY IS AN EXTREMELY FAST AND SMALL MEMORY BETWEEN CPU AND MAIN MEMORY ,IT IS ABOUT 10NS (THE ACCESS TIME OF MAIN MEMORY IS 2 OR 3 PERCENT OF THE MAIN MEMORY.
A CACHE CONTROLLER NEED FOR THE CACHE MEMORY CACHE MEMORY ARE TWO TYPE WRITE THOUGH AND WRITE BACK.
WRITE THOUGH:- IN WRITE THOUGHCACHE THE MAIN MEMORY IS UPDATED EACH TIME THE CPU WRITES INTO THE CACHE ,THE ADVANTAGE OF THE WRITE THOUGH CACHE IS THAT THE MAIN MEMORY ALWAYS CONTAINS THE SOME DATA AS THE CACHE CONTAINS.
WRITE BACK:- IN CASE OF WRITE BACK CACHE A WRITE BUFFER MAY BE INCLUDED ,IT HOLDS TEMPORARILY THE FLOG MARCHED BLOCK OF DATA ,WHICH ARE TO BE REMOVED FROM THE CACHE AND TO BE STORED IN THE MAIN MEMORY.
REAL (PHYSICAL )AND VIRTUAL MEMORY
REAL MEMORY:-THE REAL MEMORY IS THE ACTUALY MAIN MEMORY PROVIDED IN THE SYSTEM.IT IS DERECTLY ADDRESSED IN THE CPU , THE ADDRESS OF A LOCATION OF THE PHYSICAL MEMORY IS CALLED PHYSICAL ADDRESS.
VIRTUAL MEMORY:- VIRTUAL MEMORY IS AN ILLUSTRATION .IT IS A TECHNIQUE WHICH ALLOW A PROGRAMMER TO USE MAIN MEMORY MORE THAN WHAT A COMPUTER REALLY HAS IT GIVES THE PROGRAMME AN ILLUSION THAT THEY HAVE MAIN MEMORY AVAILABLE MORE THAN WHAT IS PHYSICAL PROVIDED IN THE COMPUTER.
VIRTUAL MEMORY REALIZE OR NOT ?
VIRTUAL MEMORY IS MECHANISM USES THREE BASIC CONCEPT FOR IT REALIZE
1 ONLINE SECONDARY MEMORY:- IT IS AN ONLINE SECONDARY STORAGE DEVICE HAVING MUCH LARGER CAPACITY THAN MAIN MEMORY.
2 . SWAPPING:- SWAPPING IS THE PROCESS OF TRANSFERING A BLACK OF DTA FROM ONLINE SECONDARY STORAGE TO MAIN MEMORY.
SWAPPING IN MEANS FROM ONLINE SECONDARY STORAGE TO MAIN MEMORY AND SWAPPING OUT MEANS FROM MAIN MEMORY TO ONLINE SECONDARY STORAGE.
3 DEMAND PAGING :- IN VIRTUAL MEMORY SYSTEM THE OPERATING SYSTEM PARTITIONS THE PHYSICAL MEMORY INTO PAGE FORMES OF SOME SIZE .NOW INSTEAD TO LOADING ON ENTIRE PROCESS BEFORE IT IS EXECUTION CAN START, THE OPERATING SYSTEM USE SWAPPING ALGORITHM CALLED DEMAND PAGING THE ALGORITHM SWAPS IN THOSE PAGES ONLY THE PROCESS, WHICH THE PROCESS CURRENTLY USEDS IN MEMORY FOR IT IS EXECUTION TO CONTINUE.
ADVANTAGE OF VIRTUAL MEMORY
1 IT PROVIDE A LONGER VIRTUAL MEMORY TO PROGRAMMES ON A SYSTEM HAVING SMALLER PHYSICAL MEMORY.
2 IT ENABLES EXECUTION OF A PROCESS ON A SYSTEM WHOSE MAIN MEMORY SIZE IS LESS THAN THE TALL MEMORY REQUIRED BY THE PROCESS.
3IT ENABLE A SYSTEM TO START A PROCESS EXECUTION WHEN SUFFICIENT FREE MEMORY AVAILABLE.
4 IT MAKES PROGRAMMEING TASK MUCH EASIER.
DISADVANTAGE OF VIRTUAL MEMORY
1 IT IS DIFFICULT TO IMPLEMENT BECAUSE IT REQUIRES ALGORITHMS TO SUPPORT DEMAND PAGING.
2 IT USED CARLESSLY ,IT MAY DECREASE PERFORMANCE SUBSTANTIALLY INSTEAD TO INCREASING PERFORMANCE.
STORAGE EVALUATION CRITERIA :-
ANY STORAGE UNIT OF A COMPUTER SYSTEM IS CHARACTERIZED AND EVALUATION BASED ON FOLLOWING PROPERTIES.
1 STORAGE CAPACITY:- IT IS THE AMOUNT OF DATA WHICH THE STORAGE UNIT CAN STORE LARGE STORAGE CAPACITY IS ALWAYS DISIREBLE .
2 .ACESS A TIME :- IT IS THE TIME REQUIRE TO LOCATE AND RETREEVE STORED DATA FROM THE STORAGE UNIT RESPONSE TO A PROGRAM INSTRUCTION FASTER ACCESS TIME IS PREFERABLE.
3 COST PER BIT OF STORAGE.:- IT REFERS TO THE COST OF A STORAGE UNIT FOR A GIVING STORAGE CAPACITY.
4 VOLATILE:- IT STORAGE UNIT CAN ERASE DATA STORED IN OF EVEN IN CASE OF POWER OR INTERPRETATION OF POWER IT IS CALLED NON VOLATILE STORAGE , AND ON THE OTHER HAND IT A STORAGE UNIT LOSES DATA STORED .IN CASE OF POWER OFF OR O INTERPRETATION ON POWER, IT IS CALLED VOLATILE STORAGE.
RANDOM ACCESS:- IT THE TIME OF TAKEN TO ACCESS A PRICE OF DATA FROM A LOCATION STORAGE UNIT IS INDEPENDENT OF THE LOCATION OF THE DATA IN THE STORAGE UNIT IT IS CALLED RANDOM ACCESS STORAGE ON MEMORY.
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