[conspire] Advice on Building a Computer

Peter Knaggs peter.knaggs at gmail.com
Sat Dec 29 21:16:02 PST 2007

Quoting Rick Moen:
> I like the StarTech.com ribbon cable you point to at newegg.com, because
> it includes an active terminator built right into the end of the cable.
> Without that, you'd have to muck around with terminator jumpers on the
> final hard drive of the chain, which is a pain.

For the 80-pin drives, most of them don't have any jumper,
and as far as I've seen most of the little 68 to 80-pin converters
can't do the termination either.

So for LVD SCSI, using a cable with an active terminator is certainly the
easiest way to go, if you're installing the drives inside the case.

For external LVD SCSI, usually the SCA backplane where you plug in the 80-pin
drives will have the terminator, but if you're scavenging an old case
to hold 68-pin
drives, then you'll need to add an LVD terminator (they're weirdly expensive,
probably because they're rarely needed).

I tend to find that keeping SCSI drives outside the case makes it
a lot easier to service. Taking the entire server apart just to get at the
drives can be time-consuming. If you go with a motherboard which
doesn't have on-board SCSI then adding a SCSI controller in a PCI
slot lets you connect to external SCSI enclosures.

For SCSI drives, at least the oldish ones I use, the noise level when
using RAID is quite noticable (similar to gently rattling a amall tin of
ballbearings). I tend to find that SCSI drives also seem to become a
fair bit noisier (high-pitched whine kind of noise) over time than IDE
drives. They can last for as many as five years, making this kind of
noise, before eventually failing.

These days, I've been favoring the quieter either SATA or external
firewire-attached Seagate drives. The fun thing with the external
drives is that they spin down all by themselves when they're not
being used (even while the filesystem is mounted!).
Of course, you can use scsi-spin (in the scsitools package) to spin
down SCSI drives, but it's only safe to do that after unmounting the
filesystem :)


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