Arlen Holder wrote:
On Wed, 11 Nov 2020 19:15:24 -0800, Brutus wrote:

By the by Costco has a special for a Seagate 8TB outboard hard drive for $119.99....

Funny thing you mention the Costco special of a few months ago & this month

I have both the Costco Seagate 5GB & 8GB external drive.
o For some reason, the 8GB drive _requires_ its own 12VDC power to work.

For the life of me, I can't understand why.
o I get it that the 8GB drive has bells & whistles (powered USB ports).

But why couldn't they design it to work off of the desktop USB also?

The 8TB drive is 3.5".

The power requirements are 12V for motor, 5V for logic.

3.5" drives are available up to 14TB or so in capacity
(at least, at your nearest retailer you might find them).
Some of the larger ones than that, are only intended
for data centers (host managed versus drive managed).

The 5TB drive is a 2.5". It's the largest 2.5"
they make. It runs off 5V only. 5V for motor, 5V for logic.
Generally 2.5" drives try to draw no more than 1 ampere,
and this occurs during spinup. The current consumed on
the small 15mm tall 2.5" drives, drops back once they're
up to speed.

The 2.5" drives come in a variety of heights. 7mm & 9.5mm
is useful in a laptop. The laptop bay is not big
enough to support 15mm drives. The 15mm drives were
made specifically for usage in portable external
enclosures. It's also why you don't tend to find
much information on 15mm ones, since they're not
intended to be sold as "raw" drives at retail.
As they don't fit in laptops, and nobody wants
a steady stream of customers bringing raw 15mm
drives back for a refund because they don't fit.

External drives have a USB connector. Some drives used
in such devices, the USB connector is part of the drive,
and the drive cannot be "shucked" and removed for usage
inside a SATA computer. Other external drives, there is a
separate controller board which converts SATA protocol
to USB protocol. Those sorts of drives can be taken
apart and the disk reused. It's possible the 8TB Seagate
mentioned, a 3.5", can be removed from the enclosure and
reused. The warranty is likely void if the drive is
used in this way (outside of its housing). Running the
drive serial number on the warranty page, will show the
drive itself in the bare state, has no warranty. The number
on the housing could indicate a valid warranty exists for
the entire item.

Paul