3.5" floppy drive in IBM XT?

From: Fred Cisin <cisin_at_xenosoft.com>
Date: Tue Apr 8 12:32:00 2003

> >Interesting question is whether it is being used as a 21mb MFM
> >drive or as a 33mb RLL. My guess would be 21mb.
On Tue, 8 Apr 2003, Joe wrote:
> It's an RLL drive and is 32 Mb according to my sources.

But what controller is it connected to?
The IBM controller (full length, made by Xebec) was MFM. ONLY.
When connected to an MFM controller, the drive will only be usable for 2/3
of its rated RLL capacity, giving you a very good 20M drive.

MFM and RLL gave two different recording encodings on what was otherwise
an identical drive. But many/most? MFM drives could not reliably handle
the higher "density" of RLL. Drives that were sold as RLL could.

Grumpy Ol' Fred        cisin_at_xenosoft.com
Received on Tue Apr 08 2003 - 12:32:00 BST

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