|
BIOS Color Attributes
A BIOS Color Attribute also known as VGA text mode attribute is an 8 bit value where the low 4 bits represent the character color and the high 4 bits represent the background color. The name comes from the fact that these colors are used in BIOS interrupts, specifically INT 10h, the video interrupt. When writing text to the screen, a BIOS color attribute is used to designate the color to write the text in. For example, to print a white character with a black background, a color attribute of 0F hex would be used. The high four bits are set to 0000 bin, representing the background color, black. The low 4 bits, 1111bin, represent the foreground color, white. The highest bit of the color attribute, which is also the highest bit of the background color can take over two functions. It can either have no influence on the background color making text blink when set, effectively limiting the available background colors to only eight, or if intensive background colors are enabled the full ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
VGA Text Mode
VGA text mode was introduced in 1987 by IBM as part of the VGA standard for its IBM PS/2 computers. Its use on IBM PC compatibles was widespread through the 1990s and persists today for some applications on modern computers. The main features of VGA text mode are colored (programmable 16-color palette) characters and their background, blinking, various shapes of the cursor (block/underline/hidden static/blinking), and loadable fonts (with various glyph sizes). The Linux console traditionally uses hardware VGA text modes, and the Win32 console environment has an ability to switch the screen to text mode for some text window sizes. Data arrangement Text buffer Each screen character is represented by two bytes aligned as a 16-bit word accessible by the CPU in a single operation. The lower (or character) byte is the actual code point for the current character set, and the higher (or attribute) byte is a bit field used to select various video attributes such as color, blinking ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
8-bit
In computer architecture, 8-bit integers or other data units are those that are 8 bits wide (1 octet). Also, 8-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers or data buses of that size. Memory addresses (and thus address buses) for 8-bit CPUs are generally larger than 8-bit, usually 16-bit. 8-bit microcomputers are microcomputers that use 8-bit microprocessors. The term '8-bit' is also applied to the character sets that could be used on computers with 8-bit bytes, the best known being various forms of extended ASCII, including the ISO/IEC 8859 series of national character sets especially Latin 1 for English and Western European languages. The IBM System/360 introduced byte-addressable memory with 8-bit bytes, as opposed to bit-addressable or decimal digit-addressable or word-addressable memory, although its general-purpose registers were 32 bits wide, and addresses were contained in the lower 24 bits ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Web Colors
Web colors are colors used in Web design, displaying web pages on the World Wide Web; they can be described by way of three methods: a color may be specified as an RGB color model, RGB triplet, in hexadecimal format (a ''hex triplet'') or according to its common English name in some cases. A color tool or other graphics software is often used to generate color values. In some uses, hexadecimal color codes are specified with notation using a leading number sign (#). A color is specified according to the intensity of its red, green and blue components, each represented by eight bits. Thus, there are 24 bits used to specify a web color within the sRGB gamut, and 16,777,216 colors that may be so specified. Colors outside the sRGB gamut can be specified in CSS, Cascading Style Sheets by making one or more of the red, green and blue components negative or greater than 100%, so the color space is theoretically an unbounded extrapolation of sRGB similar to scRGB. Specifying a non-sRGB ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
BIOS Interrupt Call
BIOS implementations provide interrupts that can be invoked by operating systems and application programs to use the facilities of the firmware on IBM PC compatible computers. Traditionally, BIOS calls are mainly used by DOS programs and some other software such as boot loaders (including, mostly historically, relatively simple application software that boots directly and runs without an operating system—especially game software). BIOS runs in the real address mode (Real Mode) of the x86 CPU, so programs that call BIOS either must also run in real mode or must switch from protected mode to real mode before calling BIOS and then switching back again. For this reason, modern operating systems that use the CPU in Protected mode or Long mode generally do not use the BIOS interrupt calls to support system functions, although they use the BIOS interrupt calls to probe and initialize hardware during booting. Real mode has the 1MB memory limitation, modern boot loaders (e.g. GRUB ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
INT 10h
INT 10h, INT 10H or INT 16 is shorthand for BIOS interrupt call 10 hex, the 17th interrupt vector in an x86-based computer system. The BIOS typically sets up a real mode interrupt handler at this vector that provides video services. Such services include setting the video mode, character and string output, and graphics primitives (reading and writing pixels in graphics mode). To use this call, load AH with the number of the desired subfunction, load other required parameters in other registers, and make the call. INT 10h is fairly slow, so many programs bypass this BIOS routine and access the display hardware directly. Setting the video mode, which is done infrequently, can be accomplished by using the BIOS, while drawing graphics on the screen in a game needs to be done quickly, so direct access to video RAM is more appropriate than making a BIOS call for every pixel. Furthermore, on a modern x86 system, BIOS calls can only be performed in Real mode, or Virtual 8086 mode. v8086 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hexadecimal
Hexadecimal (also known as base-16 or simply hex) is a Numeral system#Positional systems in detail, positional numeral system that represents numbers using a radix (base) of sixteen. Unlike the decimal system representing numbers using ten symbols, hexadecimal uses sixteen distinct symbols, most often the symbols "0"–"9" to represent values 0 to 9 and "A"–"F" to represent values from ten to fifteen. Software developers and system designers widely use hexadecimal numbers because they provide a convenient representation of binary code, binary-coded values. Each hexadecimal digit represents four bits (binary digits), also known as a nibble (or nybble). For example, an 8-bit byte is two hexadecimal digits and its value can be written as to in hexadecimal. In mathematics, a subscript is typically used to specify the base. For example, the decimal value would be expressed in hexadecimal as . In programming, several notations denote hexadecimal numbers, usually involving a prefi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Binary Number
A binary number is a number expressed in the Radix, base-2 numeral system or binary numeral system, a method for representing numbers that uses only two symbols for the natural numbers: typically "0" (zero) and "1" (one). A ''binary number'' may also refer to a rational number that has a finite representation in the binary numeral system, that is, the quotient of an integer by a power of two. The base-2 numeral system is a positional notation with a radix of 2. Each digit is referred to as a bit, or binary digit. Because of its straightforward implementation in digital electronic circuitry using logic gates, the binary system is used by almost all modern computer, computers and computer-based devices, as a preferred system of use, over various other human techniques of communication, because of the simplicity of the language and the noise immunity in physical implementation. History The modern binary number system was studied in Europe in the 16th and 17th centuries by Thoma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
ANSI Escape Code
ANSI escape sequences are a standard for in-band signaling to control cursor location, color, font styling, and other options on video text terminals and terminal emulators. Certain sequences of bytes, most starting with an Escape character#ASCII escape character, ASCII escape character and a bracket character, are embedded into text. The terminal interprets these sequences as commands, rather than text to display verbatim. ANSI sequences were introduced in the 1970s to replace vendor-specific sequences and became widespread in the computer equipment market by the early 1980s. Although hardware text terminals have become increasingly rare in the 21st century, the relevance of the ANSI standard persists because a great majority of terminal emulators and command consoles interpret at least a portion of the ANSI standard. History Almost all manufacturers of video terminals added vendor-specific escape sequences to perform operations such as placing the cursor at arbitrary posit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Color Graphics Adapter
The Color Graphics Adapter (CGA), originally also called the ''Color/Graphics Adapter'' or ''IBM Color/Graphics Monitor Adapter'', introduced in 1981, was IBM's first color graphics card for the IBM PC and established a De facto standard, de facto computer display standard. Hardware design The original IBM CGA graphics card was built around the Motorola 6845 display controller, came with 16 kilobytes of video memory built in, and featured several graphics and text modes. The highest display resolution of any mode was 640 × 200, and the highest color depth supported was 4-bit (16 colors). The CGA card could be connected either to a direct-drive CRT monitor using a 4-bit digital (Transistor-transistor logic, TTL) RGB(I), RGBI interface, such as the IBM 5153 color display, or to an NTSC-compatible television or composite video computer monitor, monitor via an RCA connector. The RCA connector provided only baseband video, so to connect the CGA card to a television set w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
BIOS
In computing, BIOS (, ; Basic Input/Output System, also known as the System BIOS, ROM BIOS, BIOS ROM or PC BIOS) is a type of firmware used to provide runtime services for operating systems and programs and to perform hardware initialization during the booting process (power-on startup). The firmware comes pre-installed on the computer's motherboard. The name originates from the Basic Input/Output System used in the CP/M operating system in 1975. The BIOS firmware was originally proprietary to the IBM PC; it was reverse engineered by some companies (such as Phoenix Technologies) looking to create compatible systems. The interface of that original system serves as a ''de facto'' standard. The BIOS in older PCs initializes and tests the system hardware components ( power-on self-test or POST for short), and loads a boot loader from a mass storage device which then initializes a kernel. In the era of DOS, the BIOS provided BIOS interrupt calls for the keyboard, display, st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
