TRS-80 Color Computer - Competition

Competition

The CoCo's main competition was from the Commodore VIC-20, Commodore 64, Apple II, and the Atari 400 and Atari 800.

While the CoCo sported perhaps the most advanced 8-bit processor ever made, that processing power came at a significant price premium. In order to sell the CoCo at a competitive price, its relatively expensive processor was not tied to any specialized video or sound hardware. In comparison, the 6502-derived processor in the Commodore, Apple and Atari systems was much less expensive. Both Commodore and Atari had invested in advanced graphics and sound chip design for arcade games and home gaming consoles. By tying these specialized circuits with an inexpensive processor, Atari and Commodore systems were able to play sophisticated games with high quality graphics and sound. The trade-off is between a system with an expensive CPU that does a lot of work, or an inexpensive CPU that controls the registers of its sound and video hardware.

The CoCo video hardware was derived from a chip designed as display for a character based terminal, and is a completely "dumb" device. Similarly, the sound hardware is little more than a 6-bit DAC under software control. All graphics and sound require direct CPU intervention, and while this allows for great flexibility, its performance is much lower than dedicated hardware.

Games drove system sales then as they do now, and with its poor gaming performance, the CoCo attracted little interest in officially licensed ports of popular games. The CoCo 3 did improve graphics capability and doubled CPU performance, but still contained no hardware graphics or sound acceleration. Drawing was performed by the CPU, and most of the new graphics modes required at least twice as much processor time due to increased display resolution and color depth. The sound hardware was not changed at all.

Every computer platform is a compromise, and despite the significant graphics and sound handicap the CoCo may have had, it still had a sophisticated CPU under its hood with extremely high performance. There were many independent clones of popular games available, but far more important was the availability of "killer apps" for the CoCo. For instance, CoCo-Max and Max-10 were clones of MacPaint and MacWrite. The OS-9 operating system, a UNIX-like multi-tasking multi-user environment, was also available. Even the BASIC interpreter was one of the most powerful available, and provided the user with a rich set of easy-to-use commands for manipulating on-screen graphics and playing sounds.

Some of the hardware limitations were overcome with external add-ons, particularly expansion cartridges. Some were made by Tandy, some by other manufacturers. Examples are:

• RS232 Program Pak, which provided a real RS232 UART for serial communications (the 6551A)
• The Speech & Sound Pak, which provided a speech synthesizer and a sound generator chip
• Word-Pak and Word-Pak II 80 column display adapters produced by PBJ, Inc. allowed connection to an external monochrome monitor (not needed for CoCo 3).
• 300 baud modem pak
• Advanced floppy and hard drive controllers (mostly for OS-9)

Key to taking advantage of these expansion capabilities is the Multi-Pak interface, which permits up to four devices such as these to be attached to the system at the same time.