In article ,
George K. wrote:

> But now that I'm trying to add the next 2 Seagate 750's following the
> same system, for a total of seven - no dice. One of more of the HDs
> always vanishes. Formatting of the new drives fails. Swapping cables
> and FireWire ports solves nothing.

do you have top quality firewire cabling?

> My only hunch for now is that perhaps the 300 Watt power supply in my
> enclosure is too weak to run more than five 750 Giggers along with
> their 10 cooling fans, hence all these weird problems, caused by power
> fluctuation.

that's my first guess.

> Perhaps i should plug a voltmeter into one of the
> remaining empty HD power plugs and measure what I get, as compared to
> the Seagate's +5V 0.72A and +12V 0.52A specs, printed on the label?
> (Then again, it's only a hunch...)

that's not spin-up power. i can't find the spec for spin-up power for
that drive at seagate.com but i checked a hitachi drive and it needed
+12v @ 2a and +5 @ 1.2a. that's 30 watts right there, times nine
drives is 270 watts, plus the fans, so a power issue is quite likely.

can you stagger the spin-ups so it doesn't tax the power supply?

I cannot stagger the spin-up, the enclosure has only 1 power button. I
started solving the riddle by disconnecting all the power and data
cables to ALL drives inside the enclosure. Then I connected one
Firewire connector with one ribbon cable (which I knew to be working)
to the first 2 HDs, tested them, went on the next 2 HDs, etc. This
proved that all the HD pairs spin up and work with the computer fine
by themselves. Next I started substituting the other ribbon cables,
and the other FireWire connectors. By doing this I soon established
that I of the 5 ribbon cables and 2 of the 5 FireWire connectors ("IDE
to FireWire converter bridgeboards" in fancy lingo) in the enclosure
are dead.

After throwing those away ("weeding my enclosure"... how pastoral), I
got six HDs, two per each remaining good FireWire connector / ribbon
cable to spin up and work just peachy. So we have an intermediate
solution, a pared-down rig. Now the question is, what killed so many
of these parts, could it be still a lack of juice? But how could that
kill a ribbon cable?

The answer determines what I do next. I could simply get more FireWire
connectors to replace the dead ones, and upgrade (or not) the power
supply. Or I could beef up the power supply and get ribbon cables with
4 HD connectors instead of 2 to use the remaining good FireWire
connectors. Or I could start looking into FireWire to SATA connectors
instead, from now, if this is an issue of IDE to FireWire converters
being simply poorly made. Any suggestions?