Posts tagged with “Holmes Engineering”

The Holmes Sprinter

The Holmes Sprinter was a family of speed-up boards for the TRS‑80 Model I and III. They were created and sold by Holmes Engineering, Inc., a company responsible for many hardware add-ons for the TRS‑80, such as the Expansion Mainframe, the VID-80, and the Internal Memory. The Sprinter models were probably the most popular speed-up boards available for the Model I and III.

The Sprinter I for the TRS‑80 Model I was introduced in late 1981. It cost $99.

The Holmes VID-80

The Holmes VID-80 was a popular add-on for the TRS‑80 Model I and III. Introduced by Holmes Engineering, Inc. in 1982, the VID-80 offered two related features:

It expanded the TRS‑80 screen from 64 characters wide by 16 characters high to the larger 80 characters wide by 24 characters wide.
It changed the TRS‑80 memory map to allow running the CP/M operating system.

The Holmes Expansion Mainframe

The Holmes Expansion Mainframe was a popular alternative to the Radio Shack Expansion Interface for the TRS‑80 Model I. Introduced in mid-1982, the Expansion Mainframe offered expansion options in a different manner than its competition. It provided extra features through the installation of special plug-in modules, also sold by Holmes Engineering.

The Holmes Internal Memory

Although the TRS‑80 Model I supported up to 48K of memory, there were only sockets for 16K within the Model I itself. The only official way to add more memory was to buy the Radio Shack Expansion Interface, which had sockets for an additional 32K of memory, for 48K in total. The Expansion Interface (without any memory) cost $299, making any kind of official memory expansion very expensive.

The other important feature of the Expansion Interface was the built-in floppy disk controller.