Saturday, 21 January 2012
Pengenalan angkup vernier
Satu alat mengukur jitu yang mempunyai ketepatan 1/1000" atau 1/100 mm. Angkup Vernier terdiri daripada dua bahagian iaitu satu bingkai berbentuk L dengan rahang boleh gerak dan satu bingkai yang mengandungi batang dengan rahang tetap (jaw). Batang mempunyai skala utama dalam inci(imperial scale) dan metrik (metric scale). Rahang boleh gerak mengelangsar di sepanjang batang. Bacaan boleh dikunci ke batang oleh satu skru pengapit (locking screw).Rahang luar ( External jaw) boleh mengukur garisan diameter bulatan, ketebalan dan panjang benda kerja. Rahang dalam (external jaw) boleh mengukur jarak, garis pusat gerek dan lubang, manakala bilah kedalaman (depth measuring blade) boleh mengukur kedalaman sesuatu lubang
Monday, 16 January 2012
HISTORY OF FIFTH GENERATION OF COMPUTER(1985 and PRESENT)
THE FOURTH GENERATION OF COMPUTING SPANNED FROM 1975 TO 1985. COMPUTER TECHNOLOGY HAD ADVANCED SO RAPIDLY THAT COMPUTERS COULD FIT IN SOMETHING THE SIZE OF A TYPEWRITER. THESE WERE CALLED MICROCOMPUTERS, THE FIRST ONE BEING THE ALTAIR 8800. THE ALTAIR 8800 DEBUTED IN 1975 AS A MAIL-ORDER HOBBY KIT. MANY PEOPLE ACKNOWLEDGE THE ALTAIR 8800 AS THE COMPUTER THAT SPARKED THE MODERN COMPUTER REVOLUTION, ESPECIALLY SINCE BILL GATES AND PAUL ALLEN FOUNDED MICROSOFT WITH A PROGRAMMING LANGUAGE CALLED ALTAIR BASIC– MADE SPECIFICALLY FOR THE 8800. NOW THAT COMPUTERS COULD FIT ON DESKS THEY BECAME MUCH MORE COMMON.
A SMALL COMPANY CALLED APPLE COMPUTER, INC. WAS ESTABLISHED IN 1976 AND SINGLE HANDEDLY CHANGED THE INDUSTRY FOREVER. STEVE WOZNIAK AND STEVE JOBS BEGAN TO SELL THEIR APPLE 1 COMPUTER THAT SAME YEAR, AND IT QUICKLY GAINED POPULARITY. IT CAME WITH A KEYBOARD AND ONLY REQUIRED A MONITOR TO BE PLUGGED INTO THE BACK OF THE SYSTEM, WHICH WAS A NOVEL IDEA FOR COMPUTERS AT THAT TIME. THE APPLE II WAS RELEASED THE NEXT YEAR AND WAS THE FIRST MASS PRODUCED MICROCOMPUTER TO BE COMMERCIALLY SOLD, AND ALSO USHERED IN THE ERA OF PERSONAL COMPUTING.
IN 1981, MICROSOFT DISK OPERATING SYSTEM (MS-DOS) WAS RELEASED TO RUN ON THE INTEL 8086 MICROPROCESSOR. OVER THE NEXT FEW YEARS MS-DOS BECAME THE MOST POPULAR OPERATING SYSTEM IN THE WORLD, EVENTUALLY LEADING TO MICROSOFT WINDOWS 1.0 BEING RELEASED IN 1985. IN 1984 APPLE INTRODUCED THEIR MAC OS, WHICH WAS THE FIRST OPERATING SYSTEM TO BE COMPLETELY GRAPHICAL. BOTH MAC OS AND WINDOWS USED PULL-DOWN MENUS, ICONS, AND WINDOWS TO MAKE COMPUTING MORE USER-FRIENDLY. COMPUTERS WERE NOW BEING CONTROLLED WITH A MOUSE AS WELL AS KEYBOARD. THE FIRST MOUSE WAS DEVELOPED IN 1981 BY XEROX.
SOFTWARE BECAME MUCH MORE COMMON AND DIVERSE DURING THIS PERIOD WITH THE DEVELOPMENT OF SPREADSHEETS, DATABASES, AND DRAWING PROGRAMS. COMPUTER NETWORKS AND E-MAIL BECAME MUCH MORE PREVALENT AS WELL.
THE FIRST TRULY PORTABLE COMPUTER, CALLED THE OSBORNE 1, WAS RELEASED IN 1981. PORTABLE COMPUTERS LIKE THE TRS-80 MODEL 100 / 102 AND IBM 5155 FOLLOWED AFTERWARD.
NOT ALL THE COMPUTERS OF THE TIME WERE SMALL, OF COURSE. THERE WERE STILL BEING SUPERCOMPUTERS BUILT WITH THE AIM OF BEING AS FAST AS POSSIBLE. THESE SUPERCOMPUTERS WERE SOLD TO COMPANIES, UNIVERSITIES, AND THE MILITARY. AN EXAMPLE OF ONE SUCH SUPERCOMPUTER IS THE CRAY-1, WHICH WAS RELEASED IN 1976 BY CRAY RESEARCH. IT BECAME ONE OF THE BEST KNOWN AND MOST SUCCESSFUL SUPERCOMPUTERS EVER FOR ITS UNIQUE DESIGN AND FAST SPEED OF 250 MFLOPS.
THIS GENERATION WAS ALSO IMPORTANT FOR THE DEVELOPMENT OF EMBEDDED SYSTEMS. THESE ARE SPECIAL SYSTEMS, USUALLY VERY TINY, THAT HAVE COMPUTERS INSIDE TO CONTROL THEIR OPERATION. THESE EMBEDDED SYSTEMS WERE PUT INTO THINGS LIKE CARS, THERMOSTATS, MICROWAVE OVENS, WRISTWATCHES, AND MORE
A SMALL COMPANY CALLED APPLE COMPUTER, INC. WAS ESTABLISHED IN 1976 AND SINGLE HANDEDLY CHANGED THE INDUSTRY FOREVER. STEVE WOZNIAK AND STEVE JOBS BEGAN TO SELL THEIR APPLE 1 COMPUTER THAT SAME YEAR, AND IT QUICKLY GAINED POPULARITY. IT CAME WITH A KEYBOARD AND ONLY REQUIRED A MONITOR TO BE PLUGGED INTO THE BACK OF THE SYSTEM, WHICH WAS A NOVEL IDEA FOR COMPUTERS AT THAT TIME. THE APPLE II WAS RELEASED THE NEXT YEAR AND WAS THE FIRST MASS PRODUCED MICROCOMPUTER TO BE COMMERCIALLY SOLD, AND ALSO USHERED IN THE ERA OF PERSONAL COMPUTING.
IN 1981, MICROSOFT DISK OPERATING SYSTEM (MS-DOS) WAS RELEASED TO RUN ON THE INTEL 8086 MICROPROCESSOR. OVER THE NEXT FEW YEARS MS-DOS BECAME THE MOST POPULAR OPERATING SYSTEM IN THE WORLD, EVENTUALLY LEADING TO MICROSOFT WINDOWS 1.0 BEING RELEASED IN 1985. IN 1984 APPLE INTRODUCED THEIR MAC OS, WHICH WAS THE FIRST OPERATING SYSTEM TO BE COMPLETELY GRAPHICAL. BOTH MAC OS AND WINDOWS USED PULL-DOWN MENUS, ICONS, AND WINDOWS TO MAKE COMPUTING MORE USER-FRIENDLY. COMPUTERS WERE NOW BEING CONTROLLED WITH A MOUSE AS WELL AS KEYBOARD. THE FIRST MOUSE WAS DEVELOPED IN 1981 BY XEROX.
SOFTWARE BECAME MUCH MORE COMMON AND DIVERSE DURING THIS PERIOD WITH THE DEVELOPMENT OF SPREADSHEETS, DATABASES, AND DRAWING PROGRAMS. COMPUTER NETWORKS AND E-MAIL BECAME MUCH MORE PREVALENT AS WELL.
THE FIRST TRULY PORTABLE COMPUTER, CALLED THE OSBORNE 1, WAS RELEASED IN 1981. PORTABLE COMPUTERS LIKE THE TRS-80 MODEL 100 / 102 AND IBM 5155 FOLLOWED AFTERWARD.
NOT ALL THE COMPUTERS OF THE TIME WERE SMALL, OF COURSE. THERE WERE STILL BEING SUPERCOMPUTERS BUILT WITH THE AIM OF BEING AS FAST AS POSSIBLE. THESE SUPERCOMPUTERS WERE SOLD TO COMPANIES, UNIVERSITIES, AND THE MILITARY. AN EXAMPLE OF ONE SUCH SUPERCOMPUTER IS THE CRAY-1, WHICH WAS RELEASED IN 1976 BY CRAY RESEARCH. IT BECAME ONE OF THE BEST KNOWN AND MOST SUCCESSFUL SUPERCOMPUTERS EVER FOR ITS UNIQUE DESIGN AND FAST SPEED OF 250 MFLOPS.
THIS GENERATION WAS ALSO IMPORTANT FOR THE DEVELOPMENT OF EMBEDDED SYSTEMS. THESE ARE SPECIAL SYSTEMS, USUALLY VERY TINY, THAT HAVE COMPUTERS INSIDE TO CONTROL THEIR OPERATION. THESE EMBEDDED SYSTEMS WERE PUT INTO THINGS LIKE CARS, THERMOSTATS, MICROWAVE OVENS, WRISTWATCHES, AND MORE
HISTORY OF FORTH GENERATION OF COMPUTER(1975-1985)
THE FOURTH GENERATION OF COMPUTING SPANNED FROM 1975 TO 1985. COMPUTER TECHNOLOGY HAD ADVANCED SO RAPIDLY THAT COMPUTERS COULD FIT IN SOMETHING THE SIZE OF A TYPEWRITER. THESE WERE CALLED MICROCOMPUTERS, THE FIRST ONE BEING THE ALTAIR 8800. THE ALTAIR 8800 DEBUTED IN 1975 AS A MAIL-ORDER HOBBY KIT. MANY PEOPLE ACKNOWLEDGE THE ALTAIR 8800 AS THE COMPUTER THAT SPARKED THE MODERN COMPUTER REVOLUTION, ESPECIALLY SINCE BILL GATES AND PAUL ALLEN FOUNDED MICROSOFT WITH A PROGRAMMING LANGUAGE CALLED ALTAIR BASIC– MADE SPECIFICALLY FOR THE 8800. NOW THAT COMPUTERS COULD FIT ON DESKS THEY BECAME MUCH MORE COMMON.
A SMALL COMPANY CALLED APPLE COMPUTER, INC. WAS ESTABLISHED IN 1976 AND SINGLE HANDEDLY CHANGED THE INDUSTRY FOREVER. STEVE WOZNIAK AND STEVE JOBS BEGAN TO SELL THEIR APPLE 1 COMPUTER THAT SAME YEAR, AND IT QUICKLY GAINED POPULARITY. IT CAME WITH A KEYBOARD AND ONLY REQUIRED A MONITOR TO BE PLUGGED INTO THE BACK OF THE SYSTEM, WHICH WAS A NOVEL IDEA FOR COMPUTERS AT THAT TIME. THE APPLE II WAS RELEASED THE NEXT YEAR AND WAS THE FIRST MASS PRODUCED MICROCOMPUTER TO BE COMMERCIALLY SOLD, AND ALSO USHERED IN THE ERA OF PERSONAL COMPUTING.
IN 1981, MICROSOFT DISK OPERATING SYSTEM (MS-DOS) WAS RELEASED TO RUN ON THE INTEL 8086 MICROPROCESSOR. OVER THE NEXT FEW YEARS MS-DOS BECAME THE MOST POPULAR OPERATING SYSTEM IN THE WORLD, EVENTUALLY LEADING TO MICROSOFT WINDOWS 1.0 BEING RELEASED IN 1985. IN 1984 APPLE INTRODUCED THEIR MAC OS, WHICH WAS THE FIRST OPERATING SYSTEM TO BE COMPLETELY GRAPHICAL. BOTH MAC OS AND WINDOWS USED PULL-DOWN MENUS, ICONS, AND WINDOWS TO MAKE COMPUTING MORE USER-FRIENDLY. COMPUTERS WERE NOW BEING CONTROLLED WITH A MOUSE AS WELL AS KEYBOARD. THE FIRST MOUSE WAS DEVELOPED IN 1981 BY XEROX.
SOFTWARE BECAME MUCH MORE COMMON AND DIVERSE DURING THIS PERIOD WITH THE DEVELOPMENT OF SPREADSHEETS, DATABASES, AND DRAWING PROGRAMS. COMPUTER NETWORKS AND E-MAIL BECAME MUCH MORE PREVALENT AS WELL.
THE FIRST TRULY PORTABLE COMPUTER, CALLED THE OSBORNE 1, WAS RELEASED IN 1981. PORTABLE COMPUTERS LIKE THE TRS-80 MODEL 100 / 102 AND IBM 5155 FOLLOWED AFTERWARD.
NOT ALL THE COMPUTERS OF THE TIME WERE SMALL, OF COURSE. THERE WERE STILL BEING SUPERCOMPUTERS BUILT WITH THE AIM OF BEING AS FAST AS POSSIBLE. THESE SUPERCOMPUTERS WERE SOLD TO COMPANIES, UNIVERSITIES, AND THE MILITARY. AN EXAMPLE OF ONE SUCH SUPERCOMPUTER IS THE CRAY-1, WHICH WAS RELEASED IN 1976 BY CRAY RESEARCH. IT BECAME ONE OF THE BEST KNOWN AND MOST SUCCESSFUL SUPERCOMPUTERS EVER FOR ITS UNIQUE DESIGN AND FAST SPEED OF 250 MFLOPS.
THIS GENERATION WAS ALSO IMPORTANT FOR THE DEVELOPMENT OF EMBEDDED SYSTEMS. THESE ARE SPECIAL SYSTEMS, USUALLY VERY TINY, THAT HAVE COMPUTERS INSIDE TO CONTROL THEIR OPERATION. THESE EMBEDDED SYSTEMS WERE PUT INTO THINGS LIKE CARS, THERMOSTATS, MICROWAVE OVENS, WRISTWATCHES, AND MORE
A SMALL COMPANY CALLED APPLE COMPUTER, INC. WAS ESTABLISHED IN 1976 AND SINGLE HANDEDLY CHANGED THE INDUSTRY FOREVER. STEVE WOZNIAK AND STEVE JOBS BEGAN TO SELL THEIR APPLE 1 COMPUTER THAT SAME YEAR, AND IT QUICKLY GAINED POPULARITY. IT CAME WITH A KEYBOARD AND ONLY REQUIRED A MONITOR TO BE PLUGGED INTO THE BACK OF THE SYSTEM, WHICH WAS A NOVEL IDEA FOR COMPUTERS AT THAT TIME. THE APPLE II WAS RELEASED THE NEXT YEAR AND WAS THE FIRST MASS PRODUCED MICROCOMPUTER TO BE COMMERCIALLY SOLD, AND ALSO USHERED IN THE ERA OF PERSONAL COMPUTING.
IN 1981, MICROSOFT DISK OPERATING SYSTEM (MS-DOS) WAS RELEASED TO RUN ON THE INTEL 8086 MICROPROCESSOR. OVER THE NEXT FEW YEARS MS-DOS BECAME THE MOST POPULAR OPERATING SYSTEM IN THE WORLD, EVENTUALLY LEADING TO MICROSOFT WINDOWS 1.0 BEING RELEASED IN 1985. IN 1984 APPLE INTRODUCED THEIR MAC OS, WHICH WAS THE FIRST OPERATING SYSTEM TO BE COMPLETELY GRAPHICAL. BOTH MAC OS AND WINDOWS USED PULL-DOWN MENUS, ICONS, AND WINDOWS TO MAKE COMPUTING MORE USER-FRIENDLY. COMPUTERS WERE NOW BEING CONTROLLED WITH A MOUSE AS WELL AS KEYBOARD. THE FIRST MOUSE WAS DEVELOPED IN 1981 BY XEROX.
SOFTWARE BECAME MUCH MORE COMMON AND DIVERSE DURING THIS PERIOD WITH THE DEVELOPMENT OF SPREADSHEETS, DATABASES, AND DRAWING PROGRAMS. COMPUTER NETWORKS AND E-MAIL BECAME MUCH MORE PREVALENT AS WELL.
THE FIRST TRULY PORTABLE COMPUTER, CALLED THE OSBORNE 1, WAS RELEASED IN 1981. PORTABLE COMPUTERS LIKE THE TRS-80 MODEL 100 / 102 AND IBM 5155 FOLLOWED AFTERWARD.
NOT ALL THE COMPUTERS OF THE TIME WERE SMALL, OF COURSE. THERE WERE STILL BEING SUPERCOMPUTERS BUILT WITH THE AIM OF BEING AS FAST AS POSSIBLE. THESE SUPERCOMPUTERS WERE SOLD TO COMPANIES, UNIVERSITIES, AND THE MILITARY. AN EXAMPLE OF ONE SUCH SUPERCOMPUTER IS THE CRAY-1, WHICH WAS RELEASED IN 1976 BY CRAY RESEARCH. IT BECAME ONE OF THE BEST KNOWN AND MOST SUCCESSFUL SUPERCOMPUTERS EVER FOR ITS UNIQUE DESIGN AND FAST SPEED OF 250 MFLOPS.
THIS GENERATION WAS ALSO IMPORTANT FOR THE DEVELOPMENT OF EMBEDDED SYSTEMS. THESE ARE SPECIAL SYSTEMS, USUALLY VERY TINY, THAT HAVE COMPUTERS INSIDE TO CONTROL THEIR OPERATION. THESE EMBEDDED SYSTEMS WERE PUT INTO THINGS LIKE CARS, THERMOSTATS, MICROWAVE OVENS, WRISTWATCHES, AND MORE
HISTORY OF THIRD GENERATION OF COMPUTER(1965-1975)
THE THIRD GENERATION OF COMPUTING SPANNED FROM 1965 TO 1975. DURING THIS TIME INTEGRATED CIRCUITS WITH TRANSISTORS, RESISTORS, AND CAPACITORS WERE ETCHED ONTO A PIECE OF SILICON. THIS REDUCED THE PRICE AND SIZE OF COMPUTERS, ADDING TO A GENERAL TREND IN THE COMPUTER INDUSTRY OF MINIATURIZATION. IN 1960 THE DIGITAL EQUIPMENT CORPORATION INTRODUCED THE PROGRAMMED DATA PROCESSOR- 1 (PDP-1), WHICH CAN BE CALLED THE FIRST MINICOMPUTER DUE TO ITS RELATIVELY SMALL SIZE. IT IS CLASSIFIED AS A THIRD GENERATION COMPUTER BECAUSE OF THE WAY IT WAS BUILT, EVEN THOUGH IT WAS MADE BEFORE 1965. THE PDP-1 WAS ALSO THE COMPUTER THAT RAN THE VERY FIRST VIDEO GAME, CALLED SPACEWAR (WRITTEN IN 1962).
THE SOFTWARE INDUSTRY CAME INTO EXISTENCE IN THE MID 1970′S AS COMPANIES FORMED TO WRITE PROGRAMS THAT WOULD SATISFY THE INCREASING NUMBER OF COMPUTER USERS. COMPUTERS WERE BEING USED EVERYWHERE IN BUSINESS, GOVERNMENT, MILITARY, AND EDUCATION ENVIRONMENTS. BECAUSE OF THERE TARGET MARKET, THE FIRST SOFTWARE COMPANIES MOSTLY OFFERED ACCOUNTING AND STATISTICAL PROGRAMS. THIS TIME PERIOD ALSO HAD THE FIRST SET OF COMPUTING STANDARDS CREATED FOR COMPATIBILITY BETWEEN SYSTEMS.
E-MAIL ORIGINATED SOMETIME BETWEEN 1961 AND 1966, ALLOWING COMPUTER USERS TO SEND MESSAGES TO EACH OTHER AS LONG AS THEY WERE CONNECTED THROUGH A NETWORK. THIS IS CLOSELY TIED TO THE WORK THAT WAS BEING DONE ON ADVANCED RESEARCH PROJECTS AGENCY NETWORK (ARPANET), NETWORKING TECHNOLOGY AND INNOVATION THAT WOULD ONE DAY BRING THE INTERNET
THE SOFTWARE INDUSTRY CAME INTO EXISTENCE IN THE MID 1970′S AS COMPANIES FORMED TO WRITE PROGRAMS THAT WOULD SATISFY THE INCREASING NUMBER OF COMPUTER USERS. COMPUTERS WERE BEING USED EVERYWHERE IN BUSINESS, GOVERNMENT, MILITARY, AND EDUCATION ENVIRONMENTS. BECAUSE OF THERE TARGET MARKET, THE FIRST SOFTWARE COMPANIES MOSTLY OFFERED ACCOUNTING AND STATISTICAL PROGRAMS. THIS TIME PERIOD ALSO HAD THE FIRST SET OF COMPUTING STANDARDS CREATED FOR COMPATIBILITY BETWEEN SYSTEMS.
E-MAIL ORIGINATED SOMETIME BETWEEN 1961 AND 1966, ALLOWING COMPUTER USERS TO SEND MESSAGES TO EACH OTHER AS LONG AS THEY WERE CONNECTED THROUGH A NETWORK. THIS IS CLOSELY TIED TO THE WORK THAT WAS BEING DONE ON ADVANCED RESEARCH PROJECTS AGENCY NETWORK (ARPANET), NETWORKING TECHNOLOGY AND INNOVATION THAT WOULD ONE DAY BRING THE INTERNET
HISTORY OF SECOND GENERATION OF COMPUTER(1957-1965)
THE SECOND GENERATION OF COMPUTING TOOK PLACE BETWEEN 1957 AND 1965. COMPUTERS WERE NOW IMPLEMENTING TRANSISTORS, WHICH HAD BEEN INVENTED IN 1947 BY A GROUP OF RESEACHERS AT BELL LABORATORIES, INSTEAD OF VACUUM TUBES. BECAUSE OF THE TRANSISTOR AND ADVANCES IN ELECTRICAL ENGINEERING, COMPUTERS WERE NOW CHEAPER, FASTER, MORE RELIABLE, AND CHEAPER THAN EVER BEFORE. MORE UNIVERSITIES, BUSINESSES, AND GOVERNMENT AGENCIES COULD ACTUALLY AFFORD COMPUTERS NOW. IN 1957 THE FIRST FORTRAN COMPILER WAS RELEASED. FORTRAN WAS THE FIRST HIGH-LEVEL PROGRAMMING LANGUAGE EVER MADE. IT WAS DEVELOPED BY IBM FOR SCIENTIFIC AND ENGINEERING USE. IN 1959, THE COMMON BUSINESS-ORIENTED LANGUAGE (COBOL) PROGRAMMING LANGUAGE WAS RELEASED. WHERE FORTRAN WAS DESIGNED FOR SCIENCE AND ENGINEERING, COBOL WAS DESIGNED TO SERVE BUSINESS ENVIRONMENTS WITH THEIR FINANCES AND ADMINISTRATIVE TASKS. THESE TWO PROGRAMMING LANGUAGES ESSENTIALLY HELPED TO CREATE THE OCCUPATION OF A PROGRAMMER. BEFORE THESE LANGUAGES, PROGRAMMING COMPUTERS REQUIRED ELECTRICAL ENGINEERING KNOWLEDGE. THIS GENERATION OF COMPUTERS ALSO HAD AN INCREASE IN THE USE OF CORE MEMORY AND DISKS FOR MASS STORAGE. A NOTABLE COMPUTER TO MENTION FROM THIS TIME PERIOD IS THE IBM SYSTEM/360, A MAINFRAME COMPUTER THAT IS CONSIDERED ONE OF THE IMPORTANT MILESTONES IN THE INDUSTRY. IT WAS ACTUALLY A FAMILY OF COMPUTER MODELS THAT COULD BE SOLD TO A WIDE VARIETY OF BUSINESSES AND INSTITUTIONS.
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