Re: Reading non-MFM disks in PC with a "small adapter"

From: Nicolas Welte (
Date: 2001-11-20 14:31:32

Hársfalvi Levente wrote:
> Whew, then probably the only "easy" way to go is to insert the disk with
> its proper side, and catch the data from the head above the disk +
> reverse the stream. Problems: I seem to remember of some alignment
> problems when trying to read tracks recorded using the opposite head
> ( it true, BTW? I haven't done measurements regarding this
> problem). And probably some pulse timing problems in the write process,
> but that's just another issue...

I don't know if there are any alignment problems (i.e. the head not being
centered correctly on the tracks), but there are for sure problems with the
head stop, because there is an offset of maybe three tracks between the two
heads, and it is mechanically impossible for the upper head to read the first
few tracks of a flipped disk.

I don't know if it has been reported on this list, but Jochen Adler made a
very interesting program, that displays the directory of a flippy mode
recorded disk in a 1571! I quote his original message:


-------- Original Message --------
Subject: [SC-list] 1571 reads second side
Date: Sat, 30 Jun 2001 22:12:49 +0100
From: Jochen Adler <>
References: <>


I made a programm that reads in a 1571 the second side of a 1541 disk
without turn round the disk. It reads the blocks from end to
beginning. Because of the mechanical bump it can only read track 5 to
35. It is not possible to read track 1-4. If anybody wants this
programm please email me.

Near Letter Quantity

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