Uploaded June 2023 | Updated September 2026, 2 weeks ago

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When RLL hard drives and controllers became available for personal computers in the mid-1980s, it quickly became discovered that you could format your existing MFM hard drive using an RLL controller for a 50% gain in capacity. But not all hard drives handled this well.

Let's throw the Epson Apex Plus's 20 MB Kyocera KC-20B MFM hard drive on an RLL controller, and see if we get a 10 MB increase, or if it will fall on its face.

Table of Contents:

0:00:00 - Introduction and Background
0:20:45 - Installing the RLL controller
0:27:22 - Testing the RLL controller
0:33:12 - Low-level formatting
0:46:57 - Testing with SpinRite
1:01:28 - Conclusion

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