The Computer Revolution


The abacus was the first original mechanical counting device. It is still used in education, to demonstrate the principles of counting and arithmetics. In 1642 the Pascaline was built and invented by Blaise Pascal. The Pascaline used a counting wheel design: numbers for each digit were arranged on wheels so that a single revolution of one wheel would engage gears that turned the wheel one tenth of its revolution to its immediately left. His counting wheel design was used by all mechanical calculators until the mid 60's. Joseph- Marie Jacquard created the Jacquard loom. Holes strategically punched in a card directed the movement of needles, thread, and fabric, creating elaborate patterns. From the 1920s through the mid 1950s punched card technology improved with the addition of more punched card devices. Punched-card machine techniques had become well established and reliable, and several research groups strove to build automatic digital computers. One promising machine, Mark I constructed of standard electro mechanical parts, was built by an IBM team, handled 23-decimal- place numbers (words) and could perform all four arithmetic operations. Moreover, it had special built-in programs, or subroutines, to handle logarithms and trigonometric functions. The Mark I was originally controlled from pre punched paper tape without provision for reversal, so that automatic "transfer of control" instructions could not be programmed. Output was by card punch and electric typewriter. Although the Mark I used IBM rotating counter wheels as key components in addition to electromagnetic relays, the machine was classified as a relay computer. The outbreak of World War II produced a desperate need for computing capability, especially for the military. A high-speed electronic computer the ENIAC, Electronic Numerical Integrator and Computer (or Calculator) was built. Although difficult to operate, ENIAC was still many times faster than the previous generation of relay computers. ENIAC used vacuum tubes. It had punched-card input and output and arithmetically had 1 multiplier, 1 divider-square router, and 20 adders employing decimal "ring counters," which served as adders and also as quick-access (0.0002 seconds) read-write register storage. The executable instructions composing a program were embodied in the separate units of ENIAC, which were plugged together to form a route through the machine for the flow of computations. These connections had to be redone for each different problem, together with presetting function tables and switches. ENIAC is generally acknowledged to be the first successful high-speed electronic digital computer (EDC) and was productively used from 1946 to 1955. After the ENIAC, UNIVAC, the IBM 701, IBM 601 followed. This was the first generation of computers (1951-1959) which was characterized by the use of vacuum tubes. The invention of the transistor signaled the start of the second generation of computers(1959- 1964). Transistorized computers were more powerful, more reliable, less expensive, and cooler to operate than the vacuum tubed predecessors. The third generation of computers was characterized by computers built around integrated circuits. Of these, some historians consider IBM's System 360 line of computers the single most important innovation in the history of computers. 1971 marked the beginning of the fourth generation of computers. This was the year of large-scale integration of circuitry (i.e. more circuits per unit of space) was introduced. The computer industry experienced advances in the further miniaturization of circuitry, data communications, and design of computer hardware and software. Many companies, some new to the computer field, introduced in the 1970s the programmable MINICOMPUTER supplied with software packages. The size- reduction trend continued with the introduction of personal computers, which are programmable machines small enough and inexpensive enough to be purchased and used by individuals. Many companies, such as Apple Computer and Radio Shack, introduced very successful personal computers in the 1970s. By 1980 Apple has captured 50% of the personal computer market. In 1981 IBM announced the IBM Personal Computer or PC. By the end of 1982, 835,000 had been sold. When the software vendors began to orient their products to the IBM PC, many companies began offering IBM PC compatibles or clones. Today, the IBM PC and its clones have become a powerful standard for the microcomputer industry. How do computers operate.

They process numerical data- adding, multiplying, comparing. The data must be put into a special binary code consisting only of ones and zeros. And you have to give the computer instructions, also in a code, to tell exactly what to do with the data and in what order. These instructions are called a program. In the early days you put in instructions by flipping switches. This was called machine language. Every type of computer spoke a different language and this created a huge problem. Then a computer language was invented. It consisted of English words that the computer itself could translate into binary code. Now users could type whole lists of instructions into a computer rather than flipping switches. The first language was COBOL. It was followed by FORTRAN and BASIC. Every PC requires at least two things: a computer language and an operating system. The operating system tells the computer itself how the keyboard is connected to the screen or how to store files on a floppy disk. Examples of Operating systems are: UNIX, CPM and MS-DOS.

 

The Computer Family Tree


The very first computers were mainframes and they were as big as a garage. They were filled with vacuum tubes. Eventually the valves were replaced with transistors. Further miniaturization gave us a single piece of silicone etched with thousands of transistors. The first microprocessor was invented by INTEL. This was the chip that launched the personal computer revolution. And it was used by the Altair 8800, the first personal computer. It wasn't really a computer it was a computer KIT. You had to built it yourself and even then it usually didn't work. There was no keyboard it had a front panel with switches that you can click back and forth and some lights. Turning the Altair into useful required a computer language. So, in 1975 Paul Allen and Bill Gates developed BASIC interpreter for Altair. BASIC let the Altair be used for both fun and work. People attached terminals to the computer and began writing games, word processors, and accounting programs. Then in 1977, the Apple I was developed by Steve Jobs and Steve Wozniak. It consisted of a single circuit board that neither had a case nor a keyboard. One year later the Apple II was developed. It was much more sophisticated than the Altair and Apple I. It had a floppy disk drive controller, only eight chips instead of 35, but no monitor. Software Arts developed the first spreadsheet program Visicalc - Apple II killer application. By 1980 Apple captured 50 % of the personal computer market. Then in 1981 IBM came along. This was a company that made mainframes. They saw how successful the Apple II became, so they decided to come up with their own personal computer. Instead of building a computer from scratch, they bought components off the shelf and assemble them. This was called an open architecture (non IBM technology, non IBM software, etc.) So naturally IBM operating system was also borrowed. IBM approached Bill Gates and Garry Kildall (founder of CPM operating system) to write the operating system for its new personal computer. They decided to go with Bill Gates. IBM called its operating system PC DOS. The killer application for the IBM PC was yet another spreadsheet but called Lotus 1-2-3. After IBM launched its PC's, they were in great demand. So to be successful other manufacturers would have to build computers exactly like the IBM. How could this be done legally? The answer is reverse engineering - figuring out after something has already been created how it works, usually for the purpose of creating something that works the same way. IBM made it very easy to copy their PC. The microprocessor was available off the shelf from the Intel and the other parts came from many sources. Only one part was IBM's called the ROM-BIOS. It turned out that all major software written for IBM could runs on non IBM machines. Soon IBM was faced with huge competition, Norhtghate, Dell, Compaq. Thus IBM created an open architecture that anyone could copy. To get back on their feet IBM would design a new operating system OS/2. Meanwhile, Bill Gates was working on Windows a GUI (Graphical User Interface). At the same time Apple launched its Macintosh- the first user friendly PC. The power of precise laser- printed images and a user friendly gui gave a rise to desktop publishing which was one of the features of the Macintosh. Bill Gates was also working on a GUI, he wanted to create a GUI that sat on top of DOS . In 1985, Windows 1.0 came out. Then in 1990 Microsoft Windows version 3 came out. And finally on August 24, 1995 Windows 95 came out which combined a PC's operating system and its gui into one package. IBM created the mass market for the PC but no longer sets industry standards. The Macintosh and Microsoft Windows were engaged in a gui war, Macintosh lost.

 

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