SETI@home: Team 6100

2001 – Team 6100 has 18 members and has completed 301 work units since May 2, 2000. Over the last dozen work units, we are averaging 111 hours, 42 minutes. The total contribution of Team 6100 is 3.68 years of CPU time.

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Power Macintosh 6100The Power Macintosh 6100 (a.k.a. Performa 611x), with either a 60 or 66 MHz PowerPC 601 CPU, was the slowest* Power Mac Apple ever made, but it’s fast enough to contribute to SETI@home and Team Mac Observer.

On May 1, 2000, I set up my 6100/66 with Mac OS 8.1, 40 MB of memory, a 256 KB L2 cache, Virtual Memory turned off, and SETI@home 2.0.4 software (version 3.0.3 is now mandatory – and much slower). For maximum efficiency, I turned off AppleTalk and run SETI@home as an application, not a screen saver. By doing this, setting graphics to 640 x 480 and 1-bit color, and then rolling up the SETI@home window when the program is running, the 6100 is able to run through work units as efficiently as possible.

I was unable to connect to the SETI@home server that evening, but I did start the following afternoon. My 6100 completed its first work unit in 59 hours, 23 minutes, 13.3 seconds – not bad for a computer introduced six years earlier. This is a good fraction of the speed of my PowerBook G4/400.

Under SETI@home 3.0.3, work units are running 107-151 hours and averaging 121.3 hours. That’s much slower than with the old software, but it’s apparently doing a lot more work, too.

Still, an average of 121.3 hours is fast enough. SETI@home assumes a work unit has been lost if it doesn’t come back in a week – seven days – 168 hours. Even with SETI@home 3.0.3, these 6100s continue contributing to the effort.

The 6100 can do that. In fact, each 6100 can do about 1.4 units per week, about 70 per year. My three 6100s should be able to complete 4 units per week between them. It’s not a huge amount, but if enough 6100 owners band together, it will continue adding up.

Joining Team 6100 is easier than joining other SETI@home teams. You don’t need a password; you just need to sign on as when you first launch SETI@home.

Since this article was first posted, a lot of changes have taken place. SETI@home now uses BOINC software, which requires Mac OS X 10.4 Tiger or later, a G3 or newer Mac that can run Tiger, 200 MB of drive space, and 128 MB RAM, although 256 MB is recommended. There is no way to run any version of OS X on the 6100, so Team 6100 no longer exists. This page is retained for historical purposes.

Here’s all you have to do:

  1. Have a 6100/60 or 66 that can connect to the Internet and can run SETI@home uninterrupted for at least 120 hours per week. (No chipped or otherwise accelerated 6100s, please, this is very much a low-end project.) You should have 40 MB of physical memory so you can turn Virtual Memory off. Between the OS and SETI@home, you need about 28 MB of RAM.
  2. Download the latest SETI@home software.
  3. Configure your 6100 to run efficiently: turn off AppleTalk, QuickTime, Virtual Memory, and other unnecessary control panels and extensions. You need Internet access and should have Window Shade (which is part of the Mac OS these days).
  4. Install SETI@home and restart your computer.
  5. Sign on as “” (without quotes). Run SETI@home as an application, not as a screen saver, for fastest performance.
  6. Once SETI@home is successfully loading the first work unit, scroll up the application window. This greatly reduces the load on your 6100. (In screen saver mode with graphics running, I’ve heard it can take 400 hours to complete a work unit!)
  7. Email me with Team 6100 as the subject to let me know you’re joining the team. I’ll add you to the list below, along with details about your computer and OS.
  8. Optional: Once you’ve completed your first work unit, let me know how long it took so I can list times on this page.


  1. Dan Knight, Low End Mac, 6100/60 & 66 (3 machines), 256 KB L2 cache, 40 MB RAM, OS 8.1, VM off
  2. Brett Stroup, 6100/66
  3. Michael Bearpark, 6100, System 7.5.5
  4. Kevin (in Canada), 6100/60
  5. John Tomlinson, 6100/60, 256 KB L2 cache, 40 MB RAM, OS 8.5.1
  6. Daniel Anthony, 6100/66, 256 KB L2 cache, 40 MB RAM, OS 8, running at 256 colors in blanked screen saver mode
  7. Serge Rochat, 6100/66, 256 KB L2 cache, 40 MB RAM, OS 8.1, running at 1-bit color
  8. Melissa McGuire, 6100/66 40 MB RAM, OS 8.1, running as an app/screen saver
  9. Scott Earleywine, Performa 6115CD, 72 MB RAM, OS 8.6, HPV video card
  10. Kevin Arnold, 6100/66, 256 KB L2 cache, 134 MB RAM, OS 9.0.4, VM on, AppleTalk on/ FileSharing on, Personal Web Sharing on, XTension on. SETI@home running as a screen saver
  11. Bill, Performa 6115, 40 MB RAM, OS 8.6, 256 KB L2 cache, RAM Doubler
  12. Marco Bakker, 6100/66, 1 MB L2 cache, 72 MB RAM, OS 8.6, SETI in screen saver mode, virtual memory on
  13. Brian J. Swets, 6100/60, 256 KB L2 cache, 40 MB RAM, System 7.5.5, running windowshaded, virtual memory off
  14. James Walters, Performa 6116, 256 KB L2 cache, 72 MB RAM, Mac OS 9.1, virtual memory off
  15. Eric Carlson, 6100/66, 256 KB L2 cache, 72 MB RAM, Mac OS 9, virtual memory off, running as application/screen saver
  16. John Leiher, 6100/60, 1 MB L2 cache, 72 MB RAM, Mac OS 8.6, virtual memory off, 256 colors, AppleTalk active. First unit took 115 hours, 53 minutes.
  17. Jason Wertenberger, Performa 6110, 136 MB RAM, Mac OS 8.1, virtual memory off.
  18. Ian of Fantastic Things is running a 6100/60 with 72 MB RAM, a 256 KB L2 cache, Mac OS 8.1, virtual memory off, AppleTalk off, and SETI@home running as an application. He’s also running SETI@home on the DOS card installed inside his 6100.

Based on traffic to the 6100 page on Low End Mac, I believe the 6100 is the most widely used Macintosh out there (pre-iMac, at least), so I’m hoping Team 6100 will expand to at least 100 computers.

I hope to hear from you soon.

* Some will challenge this. We don’t consider a PowerPC-upgraded Quadra a true Power Mac and have not seen any evidence that the “Road Apple” Performa 6200/75 runs SETI@home any slower than a 6100.

Team 6100 launched 2000.05.02 – Information last updated 2001.08.14

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