Tandy Color Computer-3 The Tandy Color Computer 3 has been called by some the most powerful 8bit computer in the world. What made the CoCo3 so powerful was if you add a floppy controller cartridge, external floppy drive, a CM-8 RGB monitor and ran the CoCo3 using the OS-9 operating system. For those of you not familiar with it, OS-9 is produced by Microware, and is a UNIX-like multiuser, multitasking, windowing operating system that runs on a CoCo with 128k RAM, which is what the standard amount for a CoCo3 is. OS-9 is still supported by Microware, and in fact has even been used recently for such things as Set-top boxes. The Color Computer 3 stayed in production until 1990. The CoCo-3 used the same 6809E running at .89MHZ as prior machines, though by using a special POKE it was possible to double the clock speed of the CPU to 1.78MHZ.

Like most 8bit machines of the period, the CoCo3 has a cartridge port, joystick port, and a built in RF modulator for hooking up to your television. The screen output using the RF modulator though leaves a bit to be desired, with quite a bit of artifacting present in text, such as in the 'Extended Color Basic' that the CoCo3 boots into. To do away with this, it is best to use the RGB port on the bottom of the machine to connect a monitor such as the Tandy CM-8. The CoCo-3 supported a maximum of 16 active colors out of a total of 64 with a maximum resolution of 640x225. It also supported all the CoCo-2 video modes, with the exception of the 'semigraphics' modes, and added the following additional modes: 40 and 80 column text with true lower case, 320x192x4, 320x192x16, 640x192x2, and 640x192x4. Additionally, 320x200, 640x200, and 640x225 were available using certain POKEs within programs.

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