Understanding ASCII and Unicode (GCSE)

In this tutorial I will cover ASCII and Unicode terms for the GCSE computing course. We already know how to convert ordinary decimal numbers into binary code. We simply take the 8th place value columns for the binary table. We identify which of those numbers we need. to add the total in this case of 182 and then put ones under each of those numbers filling the remaining columns with zeros, but how can we do the same with the letters? We understand that numbers can be converted to numbers, but how do we convert letters? In binary numbers, each key on your keyboard has a number associated with it.

Every character you can type can be translated into a decimal number, for example the capital A character on your keyboards becomes the number 65. This is a standard and is recognized worldwide. is part of the ASCII table, every letter, every symbol and every number on your keyboard has a corresponding number associated with it, so a is always 65. Eskie uses seven bits; In other words, the binary numbers that these letters represent have seven bits, so we use these seven columns to create 127 different possible numbers, each of which has a numerical letter or symbol associated with it, so if we take seven bits like this we can create a binary number using 64 and one to create the number 65 which represents a, so this is the binary representation of the letter A on your keyboard with 127 different possible numbers, we can represent all uppercase or lowercase letters, all the digits 0 to 9, as well as a wide range of symbols, plus there are also commands on your keyboards. which are also represented by binary numbers, so the back button, the escape tab, the Enter key and also the delete button, which is actually the number 127, the maximum that ASCII can represent;

However, there is a problem because while these 127 different symbols and characters seem fine, they fall. well below the number of characters we often need to represent these languages, for example they are not represented in standard questions, so how do we represent all these different characters and symbols, as well as the wide range of emojis, emojis or whatever you want? Call them, the answer is that we now use Unicode. Unicode is exactly the same as ASCII for all characters zero through 127, but Unicode can use more bits than called for and can therefore represent a wider range of different symbols, so it can include all of them.

Of the alphabets there is a much wider range of symbols, as well as a wide and growing range of emojis, so to summarize them,

ascii

is a letter encoding system on the keyboard that uses seven bits, occasionally we can use an eighth bit we call extended. ASCII, which doubles the number of possible characters, although it is still well below what we need for the full set of language symbols we use, Unicode is the same as ASCII for the first 127 character symbols and Unicode can support many more characters using 8 16 or even 32 bits, which would allow us to support two thousand 147 million four hundred and eighty-three thousand six hundred and forty-seven different possible characters, that's a lot of emojis.

Now we can try this ourselves if you open notepad on your computer and type the single character a which we remember is 65 in binary and then save the file. We will see that the file size is one byte, which is a complete set of eight ones and zeros. If you do the same, but this time hold down. alt and press one and you will get a single character that looks like a smiley face in notepad. Save this and you should save it as Unicode, which will result in the file size being four bytes, which is four times larger.

It only contains one character and that's because Unicode uses 32 bits to store each character and provides support for 2 billion possible different characters, so that's the difference between ASCII and Unicode. If you have any more questions leave them below and if you like this video please like it thank you for watching