The FSD-2 Excelerator Plus, also known as the Oceanic OC-118, was one of the more successful third party Commodore 1541 clone disk drives. Reviewers at the time liked its compact size, easy ability to change device numbers, external power supply, and metal case. But even more than that, they liked it because of its really high degree of compatibility.
Why Commodore 1541 clones existed
The Commodore 1541 disk drive wasn’t Commodore’s finest moment. It had quality control issues early on. And even after Commodore sorted out those issues, it was slow and loud, and its long-term reliability wasn’t fantastic. A number of companies released clone drives that tried to be better. Usually these clone drives had their own trade-offs.
But there was a family of aftermarket Commodore-compatible drives that seemed to mostly get it right.
And like other clones, my tips for using Commodore disk drives apply to the FSD-2, Excelerator Plus, OC-118, or whatever other name you know it by.
But what was special about this family of drives? And, indeed, it does seem to be a family.
Before the FSD-2 disk drive
The existence of an FSD-2 implies the existence of an FSD-1. Indeed, there was an FSD-1 disk drive, and critics liked that drive as well. It used the same Mitsumi mechanism as the late model 1541 drives, and the design resembled the 1541 as well. It was also sold as the SKAI64 in Australia by Porchester Computers Pty. Ltd, and as the CSD-1 by Cardco, the same company who announced the Atari 2600 emulator for the VIC-20. The FSD-1’s distributor in the United States was Emerald Components International, a small company based in Eugene, Oregon.
It had a metal case and the later revisions had DIP switches to change the device number, rather than making you cut traces on the PCB to change device numbers like a 1541. It had dimensions of 2-3/4 X 6-3/8 X 13 inches and weighed 6-1/4 pounds. The PCB on the drive said “Century C-581001” on the silkscreen and it was made in Japan.
How the FSD-1 was sold
Its distributors advertised it in the back pages of computer magazines, generally undercutting Commodore’s price by about $10. I honestly don’t know how well it sold. By the time it appeared on the market, word was out that third party just drives had rather uneven compatibility. They were fine as a second drive to use for storing data or making copies, but you couldn’t count on them to work with a fast load cartridge and you also couldn’t count on them to load commercial games, because their DRM schemes frequently relied on undocumented quirks of Commodores drives.
I remember several reviews but the only review I can find now was in the October 1986 issue of Compute!’s Gazette. That review said the drive was the real deal. It reported the FSD-1 was more 1541-compatible than Commodore’s own 1571 drive was.
But about 6 months later, it was gone.
FSD-2 Excelerator Plus
But Emerald Components was back soon with another drive. This drive, variously known as the FSD-2 or Excelerator Plus, looked suspiciously like another drive on the market called the NPH-501C. And the 501C had the old familiar problems. It looked nice and worked well, but wasn’t very compatible.
But then the reviews of the FSD-2 came in. It was just as compatible as the FSD-1, but now it was smaller and lighter and had an external power supply. It looked like a third party Apple II drive. Specifically, a Mitac AD-3C. Most likely, it used the same enclosure as an Apple II drive and the same mechanism has an Apple II drive, just a different printed circuit board to make it Commodore-compatible. Plus the extra power supply since Commodore’s data connector didn’t provide power.
It wasn’t quite 100% compatible, but the overwhelming majority of commercial titles worked. Caveman Ugh-Lympics from Electronic Arts was one notable title that didn’t.
After the reviews were in, the ads got bigger. And bolder. They asked if you believe in magic. Because the compatibility was like magic.
It wasn’t magic
The ROM on the FSD-2 looked like gibberish. That’s because it was a blatant copy of Commodore’s 1541 ROM. They just obfuscated it by switching some of the pins on the data lines.
Commodore sued for copyright infringement, as they had with other drives who had resorted to copying the 1541 ROM for better compatibility. But something a little strange happened. In this case, the drive was able to remain on the market. And it started shipping with a third party ROM called Jiffydos instead.
It wasn’t big news at the time, so any details are hidden behind paywalls, if they were ever available to the public at all. Presumably, Commodore got some kind of a royalty out of the new arrangement. The profit margin on a 1541 was probably higher than the royalty arrangement, but it freed up manufacturing capacity for other products, so there’s a strong case that it was a win win situation.
Five large Commodore mail order houses, including Tenex Computer Express, Montgomery Grant, and Computer Direct/Protecto Enterprizes distributed the FSD-2. They would bundle the drive with a Commodore computer and aftermarket monitor at a slight discount from what stores like Sears charged. Most of them still carried the Commodore drive, but they promoted the third party drive more.
The drive worked well, but some owners reported the drive mechanics weren’t as good as what Commodore used, so the drives can wear down under heavy usage. The mechanism looks similar to a Teac mechanism, but it’s a less expensive clone unit.
My experience with the Excelerator Plus
I never had one of these drives, but a good friend did. He got one after his original 1541 broke and couldn’t be fixed. He liked it a lot. It took up a lot less space, ran cooler, and was quieter.
It wasn’t perfect. He had to send the drive in for service at one point. But then again, his 1541 broke too, and his Excelerator Plus was fixable. After he got it back, it worked fine, longer than his 1541 had. Curiously, the paperwork he got when the drive came back said, among other things, they installed a Jiffydos ROM. We wondered about that. Presumably that was part of the settlement with Commodore. He never got a recall on the drive, but they changed the copyright-infringing ROM when he sent his drive in for service.
Other names
Outside of the United states, the same drive was sold as the Oceanic OC-118 or OC-118N. It was also sold for a brief time as the Raritan D540 and the Master-41 in the United States.
Emerald Components, who had distributed the FSD-1, called it the FSD-2. The rest of the 5 distributors in the United States called it the Excelerator Plus.
Connection with the NPH-501C
So what about that other drive that looked almost exactly like the OC-118? That drive, the Video Logic Corporation NPH-501C, wasn’t completely 1541 compatible. But the 501C wasn’t just an OC118 with a different ROM. Kind of like the MSD Super Disk Drive, the memory layout for the I/O chips was different too, which is one of the reasons it was so incompatible. It meant they couldn’t just swap in a Commodore ROM.
I’ve also seen reports of another company, Tecmate, distributing the NPH-501C. And its firmware reported the drive as a Century Planning Corp. CX-500.
The OC118N and related drives combined the best elements of the FSD-1 and the NPH-501C to make a drive that improved on both.
I think the 501C and the OC118 both used enclosures and drive mechanisms originally intended for Apple II-compatible drives, but used a different PCB to make their product Commodore compatible. The 501C wasn’t very 1541 compatible, where the OC118 had a good degree of compatibility. Making Commodore compatible disk drives out of Apple compatible drive parts proved to be a good idea. There was a fairly large market for that because Apple charged a premium for its drives, and the parts for those drives lended themselves well to making a Commodore compatible drive.
Legacy
The Excelerator Plus and its siblings are remembered today as some of the best 1541 clones. And the presence of these drives on the market does seem to have driven Commodore to release its improved 1541-II drive. The claim of being a cheaper, faster, more reliable, and completely compatible alternative may have overstated things a bit, but it was an excellent drive.
The Commodore 64 was well along in years when these drives came onto the market, but they did hit the market early enough to make an impact.
The earlier FSD-1 drive was also a good drive, but not as common. The major problem with it today is the same as the later model 1541 and 1541C drives. The drive head in the Mitsumi drive mechanism is prone to oxidizing and going open, and the only way to fix it today is to salvage a drive head from another mechanism. If you were going to do that, you might as well replace the mechanism.
As for the NPH-501c, it’s more of a curiosity today than anything. It doesn’t seem to have been on the market very long, so it seems to be pretty rare, but rarity doesn’t always translate into value. There also has to be demand for it, and not a lot of people know the drive exists. Its nondescript appearance also makes it difficult to identify.
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.