Gamer’s Guide to the Commodore 128 Faceoff With Atari

commodore 128

The Commodore 128 was the last of Commodore Business Machine’s 8-bit computers but it was a heck of a machine. In fact, it was so crazy for its time that it wasn’t ready to go until 4 hours before the development team had to leave for the CES show where it was supposed to be unveiled.

The Commodore 64 was a juggernaut so the 128 had some big shoes to fill. Not to mention Atari’s rumored ST series that was going to make the C64 look like a kid’s toy.

Did the C128 live up to its expectations? Let’s find out.

A Brief History of the Commodore 128

The Commodore 64 was one of the best-selling personal computers in the entire industry, not only for Commodore Business Machines. CBM tried to follow it up with several revisions, like the Plus/4, 264, and 364, but none of them stuck.

The C128 was their last-ditch effort to reset things and come up with a successor worthy of the C64 legacy.

A big part of that strategy was to create a computer that took the platform into the future while retaining compatibility with the huge library of C64 games and other software.

It was no small task.

The Commodore 128 PC achieved those goals, with a 99.8% compatibility with the huge library of C64 software, particularly games. The 128 reached this achievement by including multiple CPUs, making it the first mass-market multi-processor computer.

While the C128 didn’t have as long a shelf-life as the C64, it burned bright while it lasted.

C128 Specifications

The Commodore 128 included 2 CPUs that supported 3 discrete modes:

  • 2MHz 8502 processor that powered the native C128 architecture
  • 1MHz 6510 emulation (running on the 8502) to provide 99.8% compatibility with existing Commodore 64 software
  • 1-4Mhz Zilog Z-80 processor that powered the C128’s CP/M mode

In C128 mode, you had access to 128K of RAM and an 80×25 RGB display. The display ran at 640×200 which was a higher resolution than IBM’s CGA display that wasn’t available until the early 1990s, over half a decade after the C128.

The C128 used a MOS 8563 Video Display Chip (VDC) to power the 80×25 display in C128 mode. It also housed a MOS 8564/6 Video Interface Chip (VIC) for complete backward compatibility in C64 mode.

As you might guess, that VIC chip is a direct descendant of the chip used in the VIC-20, Commodore’s first mass-market computer.

The C128 also included the MOS 6581 Sound Interface Device (SID) chip that was instrumental in making the C64 a major gaming platform. No other personal computer could match the quality of sound offered by the C64 at the time.

The Competition from Atari

The Atari 400 and 800 were two major competitors to the Commodore 64 in the early 80s, particularly for gaming. Atari’s background in game consoles gave them a lot of insight into the market compared to most other computer companies.

The 1200XL followed those models in 1983 but it started to lean more toward the computing side of things and less towards gaming. The new operating system wasn’t fully compatible with older software and it had 2 fewer joystick connectors, which upset many users.

Atari wasn’t willing to give up that easily though and they started working on a rumored “ST” line of 16-bit personal computers.

The C128 was Commodore’s ace in the hole against those new systems.

And it turned out to be a good match-up since the Atari 130ST shipped with 128K of RAM, the same as the C128. The Atari started at $400 though, roughly 30 percent more than the C128.

Gaming on the C128

The Commodore 128’s backward compatibility with the C64 was a bit of a double-edged sword. It gave the C128 a huge library of games that users could play right out of the box but it also meant the game developers had less incentive to write games that ran natively on the C128.

The result was that there weren’t many games that took advantage of the 128’s extra RAM and better graphics. One of the best Commodore 128 games that used those features was Ultima V but it was one of a small number.

Commodore wasn’t clear on how they wanted to market the C128 either. They wanted to push it as more of a business system since most home users didn’t need the multi-processor features.

That functionality was so new at the time that most people didn’t understand what it meant anyway.

CBM had also launched the 16-bit Amiga line by that time, which put the C128 between a rock and hard place. They didn’t want to impact Amiga sales by targeting the same users so they priced the 128 several hundred dollars lower even though it cost roughly the same amount to build.

The combination of few native games and an unclear promotional strategy from Commodore made the C128 a niche system that didn’t come close to matching the Commodore 64’s popularity for gaming and other home applications.

A Spot in the Personal Computer Hall of Fame

If you were into computers in the 1980s, you may not have owned a Commodore 128 but you probably wished you did. Its designers were visionaries in more ways than one.

It was the first mass-market PC with multiple processors, it was the first computer built with backward compatibility in mind, and it let you run multiple operating systems on the same machine.

All standard features on most modern PCs.

Whether you’re an Atari fan or a Commodore fan, you have to give the C128 credit for being a trailblazer in the world of personal computing.

If you want to read more about the history of personal computing and relive those early days, be sure to check out some of the other posts on Whether you’re a fan of Commodore, Apple, Atari, or any other early platform, you’ll find lots of great memories here.

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