Reading ESDI disks

[Josh Dersch]

On Thu, Feb 11, 2021 at 9:45 AM Nigel Johnson via cctalk <
cctalk at classiccmp.org> wrote:

>
> On 2021-02-11 12:41 p.m., Al Kossow via cctalk wrote:
> > On 2/11/21 9:33 AM, Nigel Johnson via cctalk wrote:
> >> I'm about to try the very same thing.
> >>
> >> I have a MicroVAX II with a sigma MSCP ESDI controller.  It can be set
> >> for soft-secoring or various numbers of hard sectors.  That is what I
> >> see is the big issue with these drives.
> >>
> >> A friend gave me two drives that had been written on a PC under *nix.
> >
> > There is little chance this will work for the same reason you can't use
> > an arbitrary disk/controller combination for PC recovery.
> >
> >
> Doesn't stop me trying, Al. Lots of things were achieved by people who
> didn't know they couldn't do it!
>
> My controller has settings for different sector sizes.  I owe it to my
> friend to try!
>

Al's right in this case.  In addition to the controller almost certainly
using a different low-level format than whatever your friend's disk was
written with, you're doubly screwed because you're using an MSCP controller
-- the Sigma's going to expect RCT and FCT blocks somewhere on the unit for
block remapping and since they're not there (and are in fact likely
unreadable due to the difference in low-level format) it will fail.

- Josh



>
>
> Nigel Johnson, MSc., MIEEE, MCSE VE3ID/G4AJQ/VA3MCU
> Amateur Radio, the origin of the open-source concept!
> Skype:  TILBURY2591 nw.johnson at ieee.org
>
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