Byte
A byte is a unit of digital information that consists of 8 bits. It is the basic unit for storing and processing data in computer systems. A single byte can represent a small amount of data, such as a single character or a small integer, and is fundamental to the operation of computers and digital devices.
7 Key excerpts on "Byte"
eBook - ePub- Andy Bailey(Author)
- 2013(Publication Date)
- Routledge(Publisher)
...Bits are grouped together to form ‘words’. It is common practice in computing to group 8 bits together to form an 8-bit word length. An 8-bit word is called a Byte and is something that was settled on through trial-and-error and due to the limitation of early computer designs, and has been around for over fifty years. Eight bits together can represent any number up to 256 (2 × 2 × 2 × 2 × 2 × 2 × 2 × 2, written as 2 8 for ease). To make Bytes useful for carrying information, various methods have been devised for splitting them up in different ways to represent different things. Figure 1.2 shows two common bit assignments. The first is into two equal halves, each half being used for a different function. For instance, the leftmost half of the Byte may be used to represent a communications channel or address, which is used to identify another device on a network. In this example, the rightmost half represents a function to be performed. In this way, devices at a specific address may perform a certain function, while other devices with different addresses will ignore this instruction. Using this example, it would then be possible to build up a control set for simple devices such as might be used to control a toy car or robotic arm. This split of an 8-Byte word into two halves became so common that 4 bits got its own jargon and is so called a nibble (the amusing principle being that a nibble is half a Byte). Figure 1.2 Common bit assignments. (A) Control data and payload. (B) Most significant bit (MSB) and least significant bit (LSB). Bits can be both at the same time. A second common way of looking at Bytes, also shown in Figure 1.2, is to assign an importance to each position and this is not an exclusive way of considering bits within a Byte. This is easy to understand, since all the bits might appear equal in importance if no other information regarding the information the bits represent is available...
eBook - ePubCybercrime and Information Technology
Theory and Practice: The Computer Network Infostructure and Computer Security, Cybersecurity Laws, Internet of Things (IoT), and Mobile Devices
- Alex Alexandrou(Author)
- 2021(Publication Date)
- CRC Press(Publisher)
...A single Byte (8 bits) represents a single character. For example, the letter A is saved as 01000001, and the number 7 is saved as 0111. The number 77 is saved as 01001101 (see Figure 1.8 and Table 1.10). FIGURE 1.8 Demonstrates the difference between a Bit and a Byte. The binary system is the main language used by computers because it is simple and reliable. Furthermore, it is efficient because it requires a minimum number of electric circuits, and is of low-cost, uses little energy, and occupies minimum space. Computers calculate conversion to binary code much faster than a human could, but it is useful to know how to do conversion by hand (see Table 1.3 Decimal vs Binary Systems and Table 1.4 Computer Data Conversion). TABLE 1.3 Decimal vs Binary System Decimal System The decimal system uses 10 digits from 0 to 9 Binary System The binary system uses only two digits, 0 & 1 The decimal system uses the powers of 10 for calculation (10 0 =1, 10 1 =10, 10 2 =100, 10 3 =1000, 10 4 =10000……). The Binary system uses the powers of 2 (2 0 =1, 2 1 =2, 2 2 =4, 2 3 =8, 2 4 =16……). TABLE 1.4 Computer Data Conversion Units (Byte prefixes) Actual number of Bytes (decimal form) Base-2 (Number of Bytes) Approximate Size in Bytes (decimal. form) Base-10 (decimal) KiloByte (KB) 1,024 2 10 One-thousand Bytes 10 3 MegaByte (MB) 1,048,576 2 20 One-million Bytes 10 6 GigaByte (GB) 1,073,742.824 2 30 One-billion Bytes 10 9 TeraByte (TB) 1,099,511,627,776 2 40 One trillion Bytes 10 12 PetaByte (PB) 1,125,899,906,842,624 2 50 One-quadrillion Bytes 10 15 ExaByte (EB) 1,152,921,504,606,846,976 2 60 One-quintillion Bytes 10 18 ZettaByte (ZB) 1,180,591,620,717,411,303,424 2 70 One-sextillion Bytes 10 21 YottaByte (YB) 1,208,925,819,614,629,174,706,176 2 80 One-septillion Bytes 10 24 Conversion from Binary to Decimal We would like to convert Binary 1001 to a decimal number...
eBook - ePub- Bruce Duyshart(Author)
- 2013(Publication Date)
- Routledge(Publisher)
...Chapter 5 Digital Data Types BASIC PRINCIPLES In some of the earliest uses of computers, the work that was carried out was often referred to as electronic data processing or EDP. 1 Even though the technologies have changed dramatically since then, the principles involved have largely remained the same. Today, practically all computers are binary based. The information contained within data files they use, are encoded using a series of binary numbers which are made up of a string of 1s or 0s known as bits (derived from the term binary digits). A bit can travel at the speed of light and has no colour, size or weight. It represents the smallest element possible in the composition of information. In almost all cases, information that is processed by a computer has to be in this binary format. Since each bit can store only two possible states, on or off, data such as numbers, text and graphics have to be described using a series of bits. Figure 5.1 illustrates a comparison between common decimal (base-ten) numbers and the binary (base-two) numbers that are used by computers. Figure 5.1 A comparison between decimal and binary numbers At the fundamental level of computing, a software application can be used to create integers, real numbers and alphabetic characters from a series of bits. More complex types of digital data such as audio, graphics, and text can also be formed. Once they have been created, data can then be stored in individual computer files for later retrieval. For example, a data file might contain a sound, a picture or some text output from a numerical analysis application. These data files can then used in the composition of digital documents, which exist at the highest level of this hierarchy, as illustrated in Figure 5.2. Figure 5.2 A representation of the flow of data When data is stored in a file, it is usually structured in a manner that is tailored to specific types of information...
eBook - ePubElectronics Explained
The New Systems Approach to Learning Electronics
- Louis E. Frenzel(Author)
- 2010(Publication Date)
- Newnes(Publisher)
...Also, keep in mind that some scientific calculators can do binary-to-decimal and decimal-to-binary conversions. Another name for a binary number is binary word. The term word is more general. It refers to a fixed group of bits that can mean numbers, letters, or special characters and codes. We say that digital equipment processes binary data words. All digital circuits and microcomputers work with a fixed-length binary word. A common binary word length in microcomputers and other digital equipment is 8 bits. All data storage, processing, manipulation, and transmission are carried out in 8-bit groups. Word lengths of 4, 8, 12, 16, 32, and 64 bits are common in digital equipment. An 8-bit word is usually called a Byte. In data communication applications, an 8-bit word is sometimes called an octet. A 4-bit word is sometimes referred to as a nibble. Maximum Decimal Value for N Bits The number of bits in a binary word determines the maximum decimal value that can be represented by that word. This maximum value is determined with the formula: M = 2 N - 1 where M is the maximum decimal value and N is the number of bits in the word. For example, what is the largest decimal number that can be represented by 4 bits? M = 2 N - 1 = 16 - 1 = 15 With 4 bits, the maximum possible number is binary 1111, or decimal 15. The maximum decimal number that can be represented with 1 Byte is 255 or 11111111. An 8-bit word greatly restricts the range of numbers that can be accommodated. But this is usually overcome by using larger words. There is one important point to know before you leave this subject. The formula M = 2 N − 1 determines the maximum decimal quantity (M) that can be represented with a binary word of N bits. This value is 1 less than the maximum number of values that can be represented...
- Ross Kirk, Andy Hunt(Authors)
- 2013(Publication Date)
- Routledge(Publisher)
...The computer follows a sequence of instructions, known as a program to carry out this manipulation. For instance, if a collection of numbers is to be added together, the program will contain a sequence of ‘addition’ instructions. The actual addition will be done in the CPU, although the numbers themselves would be fetched from the memory unit, where they are stored. This process of program execution acting on memory data is typical of computer applications. This is true whether the system is intended to be a word-processor, Internet browser, digital audio editor or any other computer based system. The instructions forming the program are stored as binary information (1s and 0s) in the memory unit. The memory also normally stores in binary form all of the information (‘data’) which will be manipulated by the program, whether this is textual information in a word-processor, or audio samples for a sound processing system, or the collection of numbers in the addition program referred to above. 7.1.2 The memory unit The memory unit typically is a vast array of D-type latches. The D-type latch was described in Chapter 6. Each latch stores one Figure 7.1 The architecture of a simple computer system. piece of binary information (a ‘1’ or a ‘0’) known as a ‘bif’. Often a number of ‘bits’ of information are collected together into larger groups; 8 bits of information grouped in this way is known as a ‘Byte’, 16 bits is often described as a ‘word’, and 32 bits as a ‘long word’, or sometimes as a ‘32-bit word’. Thus, in a computer, the memory unit might be described as a ‘32 MByte memory’. The ‘M’ stands for ‘Mega’, meaning one million. In this example (quite modest by contemporary standards), the memory would contain the equivalent of 32 × 8 × 1 million D-type latches! In many computers there are in fact two main forms of memory. One, known as ‘RAM’ (random access memory), is the D-type latch form described above...
eBook - ePub- Herbert L. Blitzer, Karen Stein-Ferguson, Jeffrey Huang(Authors)
- 2010(Publication Date)
- Academic Press(Publisher)
...In this simple example where we are using two bits, the possible bit patterns are: 00: Failed both the written and the driving exams 01: Failed the written but passed the driving 10: Passed the written but failed the driving 11: Passed both the written and the driving exams Computer systems use 1 Byte, the bit pattern with a length of 8 bits, as the basic information representation. An 8-bit binary string can represent 2 8 = 256 different bit patterns from 0000 0000 = 0 to 1111 1111 = 255 (it is common practice to leave a space between groups of four binary digits each to make it easier to read the numbers). Each pixel in a normal grayscale image takes exactly 1 Byte or 8 bits. Therefore, it can represent 256 different gray levels, starting from value 0 (black) to 255 (white). In general, n bits can represent 2 n binary bit patterns. Some camera images are represented in 16 bit pixels, but the principle is the same. Figure 12.1 illustrates how an analog signal is converted to a bit pattern. FIGURE 12.1 Conversion from an analog signal into a bit pattern. Binary representation is generally more reliable than analog representation since it has only two values, 0 and 1, and it is easy to distinguish between these even when some noise is mixed into the signal. The result is less error when signal “drifts” are embedded with noise. Figure 12.2 illustrates the digital signal has less degradation than the analog signal, which has signal drifts. FIGURE 12.2 Digital signal (square wave function in green) has less degradation than analog signal (sine wave function in blue). Using digital signal for communication can prevent signal drifts. DATA REPRESENTATION IN DIGITAL SYSTEMS One important aspect of digital system design is how information ultimately will be converted into a bit pattern. Numeric values are the most prevalent and natural type of data representation from an analog source...
eBook - ePub- J S Anderson(Author)
- 2012(Publication Date)
- Routledge(Publisher)
...In Chapter 1 we also discussed the two-transistor circuits known as bistables. It was shown how such circuits could be made to count up in binary when ‘clocked’ by an astable multivibrator, and how, more importantly, they could be used as memory devices. With eight such circuits, it was shown how a Byte (8 bits) of information could be stored. The size of a computer memory is obviously very important and is always quoted in the sales literature, or even made to form part of the model number of the machine. 64K used to be a standard memory size, but now 128K, 256K and even larger internal memories are becoming commonplace. Chapter 1 introduced and Chapter 2 analysed in some detail the nature of binary mathematics; you should now see that 128 is 2 7 and 2 8 is 256. It therefore follows that 2 10 is equal to 1024 and it is that number which is represented by the capital letter K. Hence, a 64K memory would be able to hold (64 × 1024) Bytes of data. The small letter ‘k’ is an abbreviation for kilo, which means 1000, so that a computer K is slightly larger (1024). Using the bistable memory system previously described, each bistable needs two transistors, each Byte of memory requires 8 bistables and 8K of memory requires (8 × 1024) Bytes. An 8K memory device – a memory chip – based on this system would therefore need (2 × 8 × 8 × 1024) = 131,072 transistors! It could hold 65,536 bits of information, and yet, by using integrated circuit technology, all of this can be made to fit in a tiny chip about half a centimetre by three. It is this kind of technology – the high ‘packing density’ – which has enabled the microprocessor to be produced. The heart of a computer – on a chip. RAM and ROM memories Computer memory devices come in two basic types, RAM and ROM. These words are not as helpful as they could be. RAM stands for ‘random access memory’, a term which can in fact be applied to both types...
