Mark Landin wrote:
<snip>
Also, peripherals might be available for HP9000 before they are
available for HP3000 (for instance, DDS-3, DLT libraries, Autoraid
12H, Fibre Channel, Gigabit Ethernet, were or are all available for
HP9000s before HP3000s). This is because HP wrote drivers for HP-UX
before they wrote the drivers for the same hardware for MPE/iX. This
is because 1) there are more HP-UX systems out there, so thus more
demand for new peripherals, so HP makes more money faster by
supporting HP-UX first and 2) I think HP-UX drivers are easier to
<snip>

I would like to address one point in this excellent post and that is of course,
the support of DLT libraries on the HP 3000.  Actually, the issue is not so
much the support of the library itself, which I will get to in a minute, but
rather the support of the medium itself.  MPE needed to gain support of the DLT
device and subsequently the 2000, 4000 and at last the 7000 before the
libraries could even be considered for use.  At present, the DLT7000 is the
fastest tape device supported on MPE, and it is not supported very well.  The
speeds are not yet optimum.  However even beyond this, the DLT8000 is now
available followed next year by the SuperDLT.  MPE does not support the 8000
yet.  There are much faster tape devices available in the market now, such as
IBM MagStars and StorageTek Eagles (9840) which make the DLT7000 seem to be
stuck in mud.  These devices are supported on HP-UX but not on MPE and perhaps
not for the foreseeable future.  I submit to you that support of these devices
would be beneficial.

Now back to the robotic libraries.  It is not a function of the OS to support
and maneuver these devices rather it is a function of the backup solution.  It
is a rather simple thing to get a robot to load the tape in slot 10 into drive
3.  It is a simple thing to get the robot to take the tape from drive 4 and put
it in slot 25.  It is not a simple thing to remember that last Tuesday night's
backup starts two thirds of the way on the tape in slot 31 and the next tape in
the sequence is in slot 55.  That is the domain of the backup solution.  It is
certainly not the OS function to know that a StorageTek 9740 can grow to 2964
slots and 60 drives or that an HP 7448 has 48 slots and 4 drives.  That is also
the domain of the backup solution.

The other concept that is very important with respect to robotic libraries is
library sharing.  If one is to spend the money getting one of these wonderful
devices, it makes a lot of sense to get the most use out of it.  For example,
say you have two fairly large HP 3000s.  You could conceivably get an HP 7448
DLT library, hook up all 4 drives to one of these systems and backup the other
one over the network to the first one.  Don't laugh, some people are actually
contemplating doing that.  It gets even more ludicrous when you have more than
a few systems.  The other, more desirable but more technically advanced
technique, is sharing the library whereby each HP 3000 would have 2 drives of
the same library and one of them, the library server, would control the library
for both of them.  The second system would simply send command to the library
server over the LAN for the library to execute.  This is also known as LAN-free
backup.  Throw in some fiber routers and bridges and you have the makings of a
SAN (Storage Area Network).  Anyone considering an enterprise backup solution
must look into this vital aspect, LAN speed just doesn't cut it anymore.
 Again, this is certainly not the function of the OS but rather, of the backup
solution.

Kind regards,

Denys. . .

Denys Beauchemin
HICOMP
(800) 323-8863  (281) 288-7438         Fax: (281) 355-6879
denys at hicomp.com                             www.hicomp.com