What is HAM RAM?

 

Hold and modify RAM, or H&M RAM, is a type of memory used in electronic systems to temporarily store data while it is being processed. This type of RAM is often used in systems that require a high level of data integrity, such as in industrial control systems and other mission-critical applications.

The Commodore Amiga computer is one example of a system that utilized H&M RAM. The Amiga's custom chips, known as the Agnus and Denise chips, included a feature called "hold-and-modify" mode which allowed for more efficient use of the system's memory.

In H&M mode, the Agnus chip would hold the values of certain colours in its own internal registers, and then modify those colours as needed for displaying on screen, instead of having to read the values from the main memory all the time. This allowed the Agnus chip to work more efficiently and allowed for more colours to be displayed on screen at once. This feature allowed the Amiga to display more colours on screen than other computers of the time, which had a limited colour palette.

This H&M mode was not a feature of the RAM itself, but rather a feature of the custom chips that the Amiga used. The Agnus and Denise chips were specifically designed to work with the Amiga's memory architecture, and the H&M mode was one of the ways that the custom chips utilized the system's memory to its fullest potential.

The Amiga's H&M mode was one of the many innovations that set the Amiga apart from other computers of the time. It allowed the Amiga to display more colours, and allowed for more efficient use of the system's memory. This, along with other features such as the Amiga's custom graphics and sound chips, made the Amiga a popular choice for gamers and multimedia enthusiasts.

In conclusion, Hold and modify RAM is a feature that allows a system to work efficiently by holding and modifying the data in its internal registers instead of reading it all the time from the main memory. It has been used in mission-critical systems, and was a feature in the Commodore Amiga computer, which allowed it to display more colors on screen and use memory efficiently.