Hercules Graphics Card
Hercules Graphics Card (HGC) is a computer graphics card developed in 1982 by the US company Hercules , which, thanks to its popularity, became another display standard alongside the IBM standards MDA , CGA and later EGA . Hercules brand names have been owned by Guillemot Corporation since 1999 .
It was very common in the mid-1980s and supported text and graphics at 720 × 348 pixels with 1 bit per pixel. In text mode , it was compatible with the MDA standard and supported two levels of intensity for character display. The graphics mode , however, was not supported by the BIOS of "IBM-compatible" computers , which forced the development of tricky recognition routines. The HGC was for operation with TTL - monochrome monitorsprovided, which were mostly equipped with green, amber-colored, later increasingly white ("paper white") phosphors. A chip with the designation 6845 from Motorola is responsible for the entire display . With the help of peripheral components, this chip generates the necessary TTL signal that reached the monitor.
The company Hercules produced the HRF card (Hercules RamFont) , also known as Hercules Graphics Card Plus (HGC +). This allowed up to 3072 user-defined characters to be stored in the RAM in text mode, which could be accessed in portions of 256 pieces each. On this card there was also a GB 112 chip for managing the character set possibly located in the RAM.
The Hercules card was completely replaced by the VGA cards around 1990 .
The Hercules card was also later used to connect two monitors to a PC, since the graphics page base address was B0000 hex , in contrast to A0000 hex for CGA to VGA graphics cards. That is why the card could be operated at the same time, for example, with an EGA or VGA graphics card or served as a base card for systems that were equipped with TIGA graphics accelerators. Some programs recognized the graphics card and use it to output additional information, for example in the CAD area or for debugging .
The Hercules company later also produced color graphics cards , for example the HCC ( Hercules Color Card , an EGA clone ) and the HIC ( Hercules InColor Card , color version of the HRF card, functions similarly to the EGA card). In 1999 it was bought by the Guillemot Corporation .
literature
- Heinz-Josef Bomanns: The great PC graphics book , chapter 3.4. Data Becker, 1988, ISBN 3-89011-214-5 .