[clug] Hard Disk selector - Any commercial variants?

steve jenkin sjenkin at canb.auug.org.au
Tue Mar 11 23:42:23 GMT 2008

Robert Edwards wrote on 12/3/08 9:25 AM:
> If you want to dual-boot, you can with a single drive. Better
> alternatives these days are to use virtualisation and to run one O/S
> inside of another. Also, with lots of cheap (second-hand) hardware
> available (give-aways etc.), running two completely separate systems
> is also viable in many situations.

Exactly right.
Most, but not all, the time, swapping disks is really the last thing you
want to do...
But for those times, it *has* to be another disk, not multi-boot or

> If you want to be able to connect drives for other than booting
> purposes then the availability of USB (1/2) to SATA or IDE adapters
> makes connecting a second (or third etc.) drive externally compelling
> (hot-swap works etc.).

That was my point (some seemed to miss that).
Sometimes it has to be the real deal...
BTW, there was some confusion over SATA vs e-SATA (and hence support).
The only difference is the connector - electrically & protocol-wise they
are one and the same. e-SATA allows you to put drives in other cases/places.

Completely off topic, there is now 'SCSCI over SATA' (SAS - serial
attached SCSI). Electrically compatible with SATA and drives can be
'mixed' (but not on the same 'logical volume'). Does use higher
signalling voltages, but winds back when 'mixed'.

Anyone bought or used SAS??
This page from 2006 suggests it is supported in linux kernels, but is
still to converge...

> So, from an electrical engineering point of view, I can't really see
> much point in this "selector" and can see many potential pit-falls.

I thought it a "Rough as Guts" solution. Interesting, but way too
dangerous for me ;-)

> There is probably a reason these are not readily available commercially.

Absolutely right! Good observation.

Thanks all for the replies.

> Cheers,
> Bob Edwards.

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