30 Nov
2011
30 Nov
'11
5 p.m.
Glen Slick wrote:
As a follow up to Richard's question, does anyone
have any experience
archiving an Xebec S1410 / S1410A SASI controlled drive from a
relatively modern system? If the SASI controller doesn't support the
standard SCSI Inquiry and Read Capacity commands I wouldn't expect
that you could simply connect it to a SCSI host controller on a Linux
box and "dd" the drive contents to a disk image file.
I think for starters you'll have problems connecting a SASI device to a
SCSI HBA - I've not touched this for a few years, but isn't there an extra
phase in the SCSI protocol (not to mention a couple of signals) that just
isn't there for SASI? (because SASI was more of a single-device protocol,
whereas SCSI supported multiple devices on the bus)
When I looked into this it was mainly with one of the Adaptec bridges
(which are "SCSI", but lack Inquiry support), but I had a few systems which
used the Xebec and OMTI boards, too - my conclusion was that it was easier
to build myself a completely-dumb controller and talk to the boards that
way, crafting SCSI/SASI commands in software, than it was to try and
somehow integrate[1] the boards into a Linux environment at a low level. I
got as far as rustling up some hardware, but then moved overseas - so
everything's been in storage since then; I'll get back to it one day.
[1] one issue was that the Linux kernel - at least then - "offlined"
anything that didn't respond to Inquiry at boot, so it wasn't possible to
craft sg commands and throw them at the device once booted, even if the
device itself was sufficiently SCSI-like to play nicely on the bus. Maybe
that's changed these days.
Most - possibly all - of these bridge boards seemed to support some form of
vendor-unique command to define the device parameters (even if they also
did so via board firmware or 'hidden' sectors), so I don't think any lack
of a "read capacity" type command would be an issue; it'd be a case of
issuing the necessary setup command and then from there treating the device
like a linear sequence of blocks.
Oh, one other possible gotcha with the Xebec boards - ISTR they supported
the notion of running custom firmware according to a vendor's
specifications. What I don't know is if that only went as far as
initializing device parameters, or if there might be Xebec boards out there
with firmware so tweaked that it doesn't follow any of the standard
SCSI/SASI command definitions.
cheers
Jules