What is “hardware”?

Hardware is the physical part of the computer: The case with the processor, hard drive and DVD drive, the screen, the printer. You can touch the components; they have a weight and can be installed with a screwdriver. Hardware is broken only rarely, and if so: there is warranty on hardware. You have a right to free from defects (if there are any) and return.

Software, in contrast is the non-material part of the PC, the operating system and programs, such as the writing program and the Internet Explorer. Software is installed using the keyboard and mouse. Software breaks down often. But there has never been a software developer, who would have given any guarantee on the accuracy of its software. Worse: There is no error-free software. The situation is aggravated by the fact that the users make mistakes. Everyone clicks sometimes be wrong. Statistically, almost all computer problems are caused by software errors, and operator error.

The first computers were built in the forties. Graphical user interfaces are there since the fifties. The home computer Altair 8800 1974 reached the mass market. In 1981, IBM introduced the “Personal Computer” on the market, and its plan is still plugged into any PC. The foundations were laid for today’s PC already a long time ago. The advertising and the journals give us the impression that it would be introduced permanently revolutionary innovations. Sometimes even technological regression is declared as progress. Of course, you know that advertising has the purpose to inform you, but you animate for purchase (“That’s new! The buy be sure!”), and journals must contrast with lurid articles from the competition, and of any “novelty” and every rumor write first.

The Real Innovation

In 1948, the transistor was invented and founded the Norbert Wiener cybernetics. The circuits and procedures for CPU, RAM, ROM work, floppy and hard disks were in the 60s already as “proven technology”. In 1960, the inkjet printer was invented in 1969 and 1971 of the disk laser printer. Since everything is integrated into smaller, faster and higher, but not fundamentally different.

1974 developed Intel the 8-bit processor i8080. In 1978 developed successor 16-bit processor i8086 was “compatible” design so that the programs of his predecessor after an automatic recoding were run on the i8086. Intel in 1978 against IBM obliged every new processor develop “backward compatible” – and keeps itself in the fact, as well as AMD and other processor manufacturers. “Backwards compatibility” means that old programs run on the following processors, even 30 year old programs!

In 1964, the mouse was invented in order to make working with computers easier to use. In 1973, the “Xerox Alto” a “graphical user interface” developed (English Graphical User Interface, abbreviated GUI). With the “Amiga” in 1985, it reached the mass market. In 1990, Microsoft. Initial success with a graphical add-on for DOS, which was given the name “Windows” Since then, everyone can choose whether he wants to type cryptic commands or the computer rather operated with the mouse.

In recent years, parallel processing reached the mass market. Since 2002 there is a “Hyper-Threading ‘procedure: If during the execution of a program part, a waiting time occurs (e.g., because the data has not yet arrived from memory) is changed to a different part of the program. 2006, the first “Dual Core” CPUs have been sold that contain two processing plants in the CPU. What is new is that, however. Already the British “Colossus”, which was used in 1943 for deciphering secret codes, was a parallel computer. Today’s supercomputers have thousands of processors.

Also in the field of software, many of the foundations were laid decades ago:

1. In 1974, the operating system CP / M, and in 1981 developed the mind ajar appeared MS-DOS 1.0 was the first operating system from Microsoft. Every few years, there was an enhanced version of MS-DOS; the last one had the 6.22 version number. For those who do not know DOS: This operating system does not use a mouse running in plain text mode. All commands have to type on the keyboard. Example of a DOS command: xcopy c: text * a doc: * doc / d / s / e / y. These command line options are used by many professionals, because some of these commands are much more effective than the click of a mouse, and some of the “classic” commands can be a last resort, if Windows does not work anymore.
2. With each new version of an operating system respect the developers that in addition to all improvements and all the old commands still work. This allows you to use after the transition to a more modern operating system your older, cherished programs and, of course, also use your information. This principle is called friendly (downward) compatibility. This way I can still use most of the commands that I learned in the 80s.
3. Windows 2000, XP, Vista and Windows 7 come from the start without DOS. The classic DOS commands are not disappeared. All versions of Windows have a window for DOS commands, called the command prompt. Over the years, the DOS commands have been further developed. Because many new commands have been added, one no longer speaks of DOS commands, but from command line switches. The command line is so extensive those modern Windows operating systems for server install complete with command lines to configure and use leave without even a single time to use the mouse.
4. Not only is there almost always used the Windows operating system for personal computers, but also a variety of alternative operating systems, of which Linux is the best known. The roots of these operating systems usually reach even further back than that of Windows.
5. E-mail is not as new as you might think. The first experiments were carried out in 1971. In 1979, Eric Allman, the program “Deliver Mail” finished, which was renamed in 1981 “sends mail”. The vast majority of e-mail server uses this program is still in a more advanced version of an “electronic post office.”

What is that – a number system?

A numbering system is used numbers – especially large numbers – simply and clearly display. Moreover, it should be simple to count the numbers.

With the growth of the first cities and civilizations came the need to deal with large numbers. Write down on a beer mat with a few strokes of the number of ordered beers, is clear. Noting with 300 strokes, that a resident has paid his taxes with 300 jars of wine is very confusing. Therefore, the first number systems have been invented: the Sumerian, Egyptian and later the Roman numeral system. The basic idea: For large quantities of one’s group symbols are introduced. The Romans used the letter “I” for one. Ten lines were replaced with an “X”; “C” stands for one hundred and “M” for a thousand. Additionally, there are six figures: “V” for five, “L” for 50 and “D” for 500 so you could replace the 300 lines of “CCC”. “MCCXIII” thus means the 1213th the number 132 can be written as CXXXII, IIXXXC, XCXIIX or XXXIIC. The order of the numbers does not really matter, only the total counts. Therefore, such payment systems are called “Addition systems”.

Any order of the digits causes, however, that a number are many different spellings. This is confusing. Therefore, the Romans had a rule to write the larger number from the smaller.

For the Roman numerals there is another, somewhat odd special to avoid the writing of four equal consecutive characters: in front of a larger point stands a smaller, the small of the great deducted. The numbers are shorter. One writes for the number 49, for example, “XLIX” ((50 minus 10) plus (10 minus 1)) instead of “XXXXVIIII”.

The addition and subtraction of Roman numerals is not easy, considering our current knowledge and habits. To multiply, divide, or to potentiate even be a nightmare. This is probably a major reason why the Romans are no discoveries in the fields of mathematics, physics and astronomy known.

The Indians invented the decimal system and the Arabs have it in the 13th Century to Europe. By the arithmetic books of Adam Ries it became known in Germany. This system greatly simplified the calculations.

Location	2	1	0
Status	10 2	10 1	10 0
Example	3	3	3
=	3 * 10 2	3 * 10 1	3 * 10 0
=	3 * 100	3 * 10	3 * 1

Explain the specificities of the decimal system are superior to Roman numerals?

• The decimal system is a priority system with ten digits. All figures, small or large as desired, can with ten digits (the digits 0 through 9) are formed. Ten decimal digits =.
• The decimal system is a “point’s value system “: The” value “of a digit depends on where it is a number. When a number of advances in the last position of the penultimate digit of a number (for example, if you right appends a zero), it is ten times more “value”. In the number “333″ is the number 3 three times before, where it has three different meanings: Three hundred thirty and three.
• For calculating with large numbers, there are “relatively simple” rules. Whether I expect double-digit or 20-digit numbers, the rules are the same.

Location	2	1	0
Status	2 2	2 1	2 0
Example	1	1	0
=	1 * 2 2	1 * 2 1	0 * 2 0
=	1 * 4	1 * 2	0 * 1

We use the decimal system, because we count things on ten fingers. People would have a less movable thumb; we would possibly hold the octal number for the natural system in the world. If we could have easily movable toes and would walk barefoot, perhaps the Twenties number system would be optimal. The Mayans and the Aztecs had it, and some isolated indigenous peoples are using it too.

For computers is also a priority system is used in which there are only two digits zero and one. This “binary system”, also called “dual system”, was invented by Leibniz. The name comes from the Latin: bina = pairs, duo = two. Thus z, B, the binary number “110″ in the decimal system 6 the value

As is expected in a place value system? Whether it is the rules for addition, multiplication, division and other acts, all known calculation rules apply to all place-value number systems alike.