[BBC-Micro] reading data from old hard disk
jules.richardson99 at gmail.com
Tue Jun 23 16:22:36 BST 2009
Phil Blundell wrote:
> Now, though, I discover an additional problem: the disk is using
> 256-byte sectors whereas obviously the PC is set up to expect 512. I
> can modify the driver source easily enough but I'm not sure whether the
> controller card itself can be made to work with 256 bytes per sector.
MFM disks tend to be somewhat tied to the controller which (low level)
formatted them, sadly - so yes, it's entirely possible that the controller's
making some assumptions about the low-level data format on the drive and barfing.
Couple of options:
1) Adaptec bridge, BBC micro, the modified xfer software (which works with
hard disks), and serial-link the data across to a modern machine,
2) Adaptec / Xebec / OMTI bridge , SCSI controller, PC running whatever
2.4.x kernel it was that was reported to work (by Rhys, IIRC) with the
Domesday player a few weeks ago, then whip up some C code to read raw blocks
from the drive using the sg interface.
 it's supposed to be for ADFS, but I think it's all sufficiently low-level
that you can just hack in the start and end block and let it run - assuming
that the Adaptec bridge will talk to the low level format on the drive. I
remember using it that way to drag data across from an Econet server drive.
 Some of them allowed the sector size to be specifed via jumpers, others
via software. They were generally "mostly SCSI", but the read/write commands
are generally standardised - if it works with the Domesday setup, it should
work with one of the SCSI bridges. Again, needs the low-level format of the
drive to be something that the bridge can make sense of, though.
What's the history of this drive - is that HDFS as in SJ Research, or HDFS as
in hierarchical filesystem?
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