Computing for the Bewildered by Bill Hayles THE KEYBOARD - Part 2 ===================== Hello, again. Last time, we looked at the basic use of the keyboard. Today, we'll extend our knowledge by looking at some more advanced things you can do, things that even experienced computer users don't know about. As before, we're assuming a Spanish layout. Before we start, we'll need to introduce ASCII codes. ASCII CODES ============ When the computer sends text to the printer, to another computer, or even to the screen, it does not actually send the pattern of dots which would make up the text characters, but rather a number between 0 and 255. The other device will then convert this number to a character or an operation such as a line feed. Handling text in this way is much faster, and requires much less memory than sending a dot pattern or 'bit-map'. It is therefore rather important for the devices to have the same code for the same character. The set of codes almost universally used by all computers is known as the ASCII set. ASCII stands for American Standard Code for Information Interchange, and was agreed in 1966 for use in teleprinter and other datacommunications applications. It was derived from an earlier five-bit code, named Baudot after its inventor, which had been used since the last century for tickertape machines, telexes and teleprinters. ASCII was originally defined as a seven-bit code, allowing 128 combinations (0-127). Codes 32 to 126 are defined characters, whilst 0-31 and 127 define operations, are called Control Codes, and need not concern us. For modern computers, whilst the characters assigned to 32-127 are more or less universal, the so-called Hi-ASCII, 128 to 255, may well vary, especially between Apple Mac and PC. For this reason, although I'd love to ask the editor to print out an ASCII table for me in the paper, I couldn't guarantee it would reproduce correctly or necessarily show the same characters on your computer. All is not lost, as will be explained below. On the IBM P.C. and its derivatives, 128-168 represent 'foreign' characters ; 169 to 223 are 'graphic' characters usable in text mode; 224 to 239 are Greek alphabet characters, and 240 to 253 are additional mathematical symbols. Having got that out of the way, let's start with some of the keys we didn't mention in part 1. The Alt key to the left of the space bar is a pure alternative key, working with the function keys and one or two others (except as below) The Control key (duplicate - one at the bottom left and bottom right of the main block). The main use of the control key is as an alternative key in conjunction with the function keys - Ctrl-F1 etc. Its original use, which gave it its name, was that it could be used to access the control function associated with a letter. This is now obsolete, but there is one trick worth mentioning. From within many applications, pressing Ctrl-G, the bell, will still make the computer “beep”. The Tab key (next to the “Q”) is used in text work to move the cursor a predefined number of spaces across the screen. There is a special use - Alt-Tab can be used to cycle through the programs active on your computer at any given time. The Win key (duplicate - one to the left of the Alt key, the other to the right of the Alt-Gr) is, when you are working in Windows, equivalent to pressing Ctrl-Esc and brings up the start menu. The RightWin key (between the Win key and the right Control) has the same action as pressing the right mouse button, and what appears depends on where the mouse cursor is. Only more recent keyboards have the Win and RightWin keys. The Insert key (on the action block) is a toggle key, toggling whether, when you insert characters into text the insert is additional, and nothing is deleted or whether for each character that is inserted the character already in that place is deleted. The former is the norm and the safer; my advice is not to meddle. The Scroll Lock (Bloq Despl) is, essentially, redundant. When scrolling through masses of text under DOS, the scroll lock would stop the scrolling until you were ready to move on - it's a sticky key with a status light. The Pause / Break (Pausa / Inter) is equally redundant, again used to control screen movement under DOS. I sometimes use it to pause the display of the POST if I suspect something is wrong, but that's all. Now, at last, to the tricks! Characters NOT on the keyboard ============================== In addition to the characters available directly from the keyboard, there are many others available. Accented characters. =================== You may have noticed that if you type certain characters, such as “`”,” ” and “¨”, the character only appears after you have typed the next character. If the next character is a vowel, the first character typed will appear as an accent on the vowel. In other words, to type the French name “Hélène”, I type, in order, H ´e l `e n and e. Although in Castellano the only accent we use is the acute, the Spanish keyboard copes with all accented letters, such as ü ô and à. It also has the extra letters ñ (for use in Castellano) and ç (for use in Catalan as well as French). The “Alt” trick. =============== Every character available (without the use of special character maps) has an ASCII code, as we mentioned above. Whether or not it appears on the keyboard, it can be produced by means of the Alt key. What you need to do is to make sure the Num Lock is ON. Then, hold down the Alt key, type out the three figure ASCII code of the character on the Number Pad, and release the Alt key. The character will then appear. It only works on the number pad (not on the numbers on the top row) and then only if the Num Lock is on. On the Spanish keyboard, there is only one character you'll probably need to produce in this way and that's the pound sign (£) which I've just made appear by holding down the Alt key and pressing 1 5 and 6 before releasing the Alt key - the ASCII code for the pound sign is 156. If you're using a UK keyboard, you will need to use this way to produce accented characters as well as ñ and ç. You'll need to learn, for example that é is code 130. To find out what the character set is on YOUR computer, open a text editor (Notepad is the usual) and go through all the numbers from 032 to 255 (use a 0 to make a three figure code for codes under 100) using the "Alt" trick, and see what character appears on your screen. For example, Alt-065 gives you a capital A, alt-097 a lower case a Write them down - there will be many characters you didn't know you could get so easily, such as Alt-171 for ½. A few numbers will give you nothing - don't worry, that's normal.