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Author Topic: Help Mounting A2090a MFM Seagate ST-238R  (Read 2945 times)

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Offline curtis

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Re: Help Mounting A2090a MFM Seagate ST-238R
« on: June 01, 2015, 05:10:10 PM »
ST-238R is not MFM.  It's RLL.

Won't work on a MFM controller.
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Offline curtis

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Re: Help Mounting A2090a MFM Seagate ST-238R
« Reply #1 on: June 01, 2015, 09:19:25 PM »
I stand corrected.

Guess with the RLL you get more capacity.  Formatting it MFM drops the 38MB drive back down to 20MB.

Guess the ST-238R was just a ST-225 with RLL encoding.

Hmmm, learned something today that I should've known all along!
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Re: Help Mounting A2090a MFM Seagate ST-238R
« Reply #2 on: June 01, 2015, 11:37:36 PM »
Well, there's always good ole wikipedia:
http://en.wikipedia.org/wiki/Modified_Frequency_Modulation  There's a link that explains RLL is Excruciating detail near the top of the MFM article.

An interesting thread on google groups has a pretty discussion of the differences also:
https://groups.google.com/forum/#!topic/comp.sys.ibm.pc.hardware/pc09c_yHWr8
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Re: Help Mounting A2090a MFM Seagate ST-238R
« Reply #3 on: June 02, 2015, 01:40:58 AM »
Told ya so!


Quote from: danbeaver;790383
Lord, that is a boring read.
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