🚀 go-pugleaf

In article <0096545A.661A7C40@vax.nott.ac.uk>, cczanj@vax.nott.ac.uk (Andy Jack) writes:
>
>We have a VAX 6410 that needs more disk. The existing KDB50 controller is full
>with 4 RA drives and there is a feeling that the whole system may be replaced
>next year by a 4000 series machine. It seemed a good idea to buy a KFMSA
>controller and start buying RF disks which would carry over to a 4000. An RF73
>won't go in the existing SA600 cabinet, so DEC offer us an R400X cabinet at a
>fairly high price (approx 50% of the cost of the RF73). A third party has
>offered an RF73 in a BA213 cabinet at a much lower cost but DEC say that the
>combination of a KFMSA and a BA-style cabinet for DSSI disks is not supported.
>
>Why ever not? What has the box got to do with it?

Lots of things actually.  When a particular configuration is SUPPORTED
it means that it has been qualified to work correctly in reasonably
extreme conditions.  This means that DEC doesn't believe that it will
break in normal operation nor violate typical laws, about running
radio stations and small space heaters...

The subsystem has to be tested to make sure that the box keeps in the
things in the box adequately cool and within their operating range
given reasonable outside conditions.  The subsystem has to be tested
to make sure the power supply can provide sufficient power in the
common extreme conditions (and that more extreme conditions aren't
like to be faced).  The subsystem has to be tested to make sure that
it doesn't "sound" like a small radio station to nearby radios (FCC
testing).

These are probably the most common things tested to make sure a
subsystem is supported.  It's expensive to do.  Therefore we limit
the configurations tested and supported.   In the specific example,
it is most likely the case that the combination of a BA213 was
never tested with an RF73.  Or if it was tested, problems not worth
the expense of solving were found.

If the 3rd party vendor is willing to guarantee that the disk won't
overheat in the box, that the power supply won't catch fire if you
spin up lots of disks at the same time and that your equivalent of
the FCC won't come banging on your door, go for it.
>
>	Andy
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>
--
Alan Rollow				alan@nabeth.cxo.dec.com