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29-547: The original IBM MDA was an 8-bit ISA card with a Motorola 6845 display controller, 4 KB of RAM , a DE-9 output port intended for use with an IBM monochrome monitor , and a parallel port for attachment of a printer, avoiding the need to purchase a separate card. The MDA was based on the IBM System/23 Datamaster 's display system, and was intended to support business and word processing use with its sharp, high-resolution characters. Each character

58-477: A bitmapped graphics mode, also offering a parallel printer port . This allows the HGC to offer both high-quality text and graphics from a single card. The HGC was very popular and became a widely supported de facto display standard on IBM PC compatibles . The HGC standard was used long after more technically capable systems had entered the market, especially on dual-monitor setups. The Hercules Graphics Card

87-774: A CGA or other color card at address B8000h. In text mode, the HGC appears exactly like an MDA card. Graphics mode requires new techniques to use. Unlike the MDA and CGA, the PC BIOS provides no intrinsic support for the HGC. Hercules developed extensions, called HBASIC , for IBM Advanced BASIC to add HGC support and Hercules cards came with Graph X , a software library for Hercules graphical-mode support and geometric primitives . Popular IBM PC programs such as Lotus 1-2-3 spreadsheet, AutoCAD computer-aided drafting, Pagemaker and Xerox Ventura desktop publishing, and Microsoft Flight Simulator 2.0 came with their own drivers to use

116-551: A color monitor, color appears as simulated grayscale in varying dithering patterns . Clones of the Hercules appeared, including generic models at very low prices, usually without the printer port. Hercules advertisements implied that use of generic Hercules clones can damage the monitor. The Hercules Graphics Card was very successful, especially after Lotus 1-2-3 supported it, with one-half million units sold by 1985. As of June 1986 Hercules Computer Technology had 18% of

145-527: A printer port made it more appealing for the business applications that were the focus of the original PC. However, dissatisfaction with its limitations quickly led to third parties releasing competing hardware. A well known example was the Hercules Graphics Card . Introduced in 1982, it offered both an MDA-compatible high resolution text mode and a monochrome graphics mode. The founder of Hercules Computer Technology , Van Suwannukul, created

174-540: Is limited to a fixed character set . These adapters were quickly found to be inadequate by the market, creating a demand for a card that offers high-resolution graphics and text. The founder of Hercules Computer Technology , Van Suwannukul, created the Hercules Graphics Card so that he could work on his doctoral thesis on an IBM PC using the Thai alphabet , impossible with the low resolution of CGA or

203-408: Is rendered in a box of 9 × 14 pixels , of which 7 × 11 depicts the character itself and the other pixels provide space between character columns and lines. Some characters, such as the lowercase "m", are rendered eight pixels across. The theoretical total screen display resolution of the MDA is 720 × 350 pixels, if the dimensions of all character cells are added up, but

232-764: The Hercules Network Card Plus , ( HNC NB112 ) a variant of the Graphics Card Plus with an integrated TOPS /FlashTalk-compatible network adapter. Like the HGC+, it supported RAMFONT, but lacked a printer port. The InColor Card ( GB222 ) was introduced in April 1987. It included color capabilities similar to the EGA , with 16 colors from a palette of 64. It retained the same two modes ( 80 × 25 text with redefinable fonts and 720 × 348 graphics), and

261-528: The HGC can hold two graphics display pages. Either page can be selected for display by setting a single bit in the Mode Control Register. Another bit, in a configuration register exclusive to the HGC, determines whether the second 32 KB of RAM on the HGC is accessible to the CPU at the base address B8000h. This bit is reset at system reset (e.g. power-on) so that the card does not conflict with

290-480: The Hercules Graphics Card so that he could work on his doctoral thesis on an IBM PC using the Thai alphabet , which was impossible at the low resolution of CGA or the fixed character set of MDA. It could address individual pixels, and displayed a black and white picture of 720 × 348 pixels. This resolution was superior to the CGA card, yet offered pixel-addressable graphics, so despite lacking color capability,

319-473: The Hercules adapter's offer of high resolution bitmap graphics combined with MDA-grade text quality made it a popular choice, which was even shipped with many clones . MDA cards used a DE-9 output port intended for a digital TTL monitor, like the IBM monochrome monitor. The signal had the following specifications: Other boards offer MDA compatibility , although with differences on how attributes are displayed or

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348-409: The Hercules card provides a horizontal scanning frequency of 18.425 ± 0.500 kHz and 50 Hz vertical. It runs at two slightly different sets of frequencies depending on whether in text or graphics mode, providing a different vertical refresh rate and a different aspect ratio via a different pixel clock and number of scanlines. The Hercules card provides two modes: The text mode of

377-474: The Hercules card uses the same signal timing as the MDA text mode. The Hercules graphics mode is similar to the CGA high-resolution ( 640 × 200 ) two-color mode; the video buffer contains a packed-pixel bitmap (eight pixels per byte, one bit per pixel) with the same byte format—including the pixel-to-bit mapping and byte order—as the CGA two-color graphics mode, and the video buffer is also split into interleaved banks, each 8 KB in size. However, because in

406-402: The Hercules graphics mode there are more than 256 scanlines and the display buffer size is nearly 32 KB (instead of 16 KB as in all CGA graphics modes), four interleaved banks are used in the Hercules mode instead of two as in the CGA modes. Also, to represent 720 pixels per line instead of 640 as on the CGA, each scanline has 90 bytes of pixel data instead of 80. The 64 KB RAM of

435-399: The Hercules graphics mode. Though the graphics mode of the Hercules card is not CGA-compatible, it is similar enough to the two CGA graphics modes that with the use of third-party terminate-and-stay-resident programs it can also work with programs written for the CGA card's standard graphics modes. As the Hercules card does not actually have color-generating circuitry, nor can it connect to

464-518: The MDA cannot address individual pixels to take full advantage of this resolution. Each character cell can be set to one of 256 bitmap characters stored in ROM on the card, and this character set cannot be altered from the built-in hardware code page 437 . The only way to simulate "graphics" is through ASCII art , obtaining a low resolution 80 × 25 "pixels" screen, based on character positions. Code page 437 has 256 characters (0-255), including

493-525: The PC (including text adventures ) and at least one game, IBM's One Hundred And One Monochrome Mazes , requires MDA. Box-drawing characters made the production of rudimentary graphics practical for early PC game titles, including BBS door games or titles such as Castle Adventure . Another use for the MDA was as a secondary display for debugging . Applications like SoftICE and the Windows debugger permitted

522-545: The actual display of these levels is monitor-dependent: The MDA was released alongside the IBM Color Graphics Adapter , and in fact could be installed alongside the CGA in the same computer. A command included with PC DOS permitted switching the primary display between the CGA and MDA cards. Because of the lack of pixel-addressable graphics, MDA owners were unable to play PC games released with graphics support. However, textmode games were released for

551-466: The fixed character set of MDA. It initially retailed in 1982 for $ 499. The original HGC is an 8-bit ISA card with 64 KB of RAM , visible on the board as eight 4164 RAM chips, and a DE-9 output compatible with the IBM monochrome monitor used with the MDA. Like the MDA, it includes a parallel interface for attaching a printer. The video output is 5 V TTL , as with the MDA card. Nominally,

580-632: The font used. ISA card Too Many Requests If you report this error to the Wikimedia System Administrators, please include the details below. Request from 172.68.168.151 via cp1112 cp1112, Varnish XID 929135450 Upstream caches: cp1112 int Error: 429, Too Many Requests at Thu, 28 Nov 2024 08:02:39 GMT Hercules Graphics Card The Hercules Graphics Card ( HGC ) is a computer graphics controller formerly made by Hercules Computer Technology, Inc. that combines IBM 's text-only MDA display standard with

609-506: The graphics card market, second to IBM. Hercules-compatible graphics cards shipped as standard hardware with most PC clones . As a de facto standard , support in software was widespread. The Hercules Graphics Card had several versions. Several updated versions of the original Hercules Graphics Card exist. The original board from 1982 is referenced as GB100 , with updated versions in 1983 ( GB101 ), 1984 ( GB102 ) and 1988 ( GB102Z ). The Hercules Graphics Card Plus or HGC+ ( GB112 )

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638-576: The monochrome card in such a setup for maximum speed of the VGA card. The author of an internal IBM publication stated in October 1981 that he had planned to purchase the CGA adapter but changed his mind after seeing its poor display quality. Describing MDA as beautiful, he observed that "you stare at text a whole lot more than you stare at color graphics". MDA was more popular than CGA for business applications. The higher resolution of MDA's text and inclusion of

667-464: The normally unconnected DE-9 video connector pins, theoretically allowing an 8-color display with a suitable monitor. The registers also allow the monochrome mode to be set on and off. No (widely) published software exists to actually control the feature. It is also possible to combine the values of output pins 7 ( Video) and 6 ( Intensity), to generate four brightness levels. Video corresponds to 2/3 luminance and Intensity to 1/3 luminance), but

696-412: The screen. These are invisible, underline, normal, bright (bold), reverse video, and blinking . Reverse video swaps the foreground and background colors, while blinking causes text to flash periodically. Some of these attributes can be combined, so that e.g. bright, underlined text can be rendered. Early versions of the MDA board have hardware capable of outputting red, green and blue TTL signals on

725-556: The simultaneous use of an MDA and another graphics card, with the MDA displaying a debugger interface while the other card was showing the primary display. A typical 8-bit monochrome card could turn the 16-bit 8 MHz ISA bus into an 8-bit 4 MHz PC bus , which resulted in having the bus bandwidth cut by up to 75%. If the monochrome card was added to the PC as a second card besides a normal VGA card for debugging purposes, this resulted in slow VGA performance. Microsoft recommended in its Writing HOT Games for Microsoft Windows (1994) to remove

754-463: The standard 95 printable ASCII characters from (32-126), and the 33 ASCII control codes (0-31 and 127) are replaced with printable graphic symbols. It also includes another 128 characters (128-255) like the aforementioned characters for drawing forms. Some of these shapes appear in Unicode as box-drawing characters . There are several attribute values - bit flags that can be set on each character on

783-495: Was backward-compatible with software written for the earlier monochrome Hercules cards. The Hercules Color Card ( GB200 ) was a CGA-compatible video board and should not be confused with the InColor Card. This board could coexist with the HGC and still allow both graphics pages to be used. It would detect when the second graphics page was selected and disable access to its own memory, which would otherwise have been at

812-584: Was released in June 1986 at an original retail price of $ 299. It was an enhancement of the HGC, adding support for redefinable fonts called RAMFONT in MDA -compatible text mode. It was based around a specialty chip designed by Hercules Computer Technology, unlike the original Hercules Graphics Card, which used standard components. Software support included Lotus 1-2-3  v2, Symphony  1.1, Framework II and Microsoft Word  3. In 1988 Hercules released

841-703: Was released to fill a gap in the IBM video product lineup. When the IBM Personal Computer was launched in 1981, it had two graphics cards available: the Color Graphics Adapter (CGA) and the Monochrome Display And Printer Adapter (MDA). CGA offered low-resolution ( 320 × 200 ) color graphics and medium-resolution ( 640 × 200 ) monochrome graphics, while MDA offers a sharper text mode (equivalent to 720 × 350 ) but has no per-pixel addressing modes and

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