Z Man said:
I have a Hitachi 7k500 hard drive in an external SATA case. I don't use
this drive all the time, and I prefer to turn it off when not in use.
However, if I simply turn off the power, it seems to lock up my computer.
Is there a 'right way' to turn off my external SATA drive when the computer
is powered up?
Based on our contacts with the SATA-IO organization
(
http://www.sata-io.org), the lead organization developing specifications
for the SATA-IO HDs, (the "IO" denoting "International Organization"),
formerly called SATA-II (and apparently still known by that latter
designation by most users), and a number of HD manufacturers, here's what
we've been able to glean re this "hot-plugging" issue as it applies to SATA
HDs...
There are two basic requirements for SATA hard drives to be "hot-pluggable"
(a/k/a "hot-swappable"), to wit...
1. The SATA HD must have this capability. The manufacturer must
*specifically*
indicate that the particular drive is hot-pluggable capable. BTW, both the
earlier SATA
HDs having a data transfer rate of 1.5 Gb/s and the latest SATA-IO HDs
having a data transfer rate of 3 Gb/s can be hot-pluggable. According to the
information we received from the SATA-IO organization, the user cannot
assume that merely because the drive is designated SATA-IO (SATA-II) it is
inherently hot-pluggable. It would seem that in theory this *should* be so
presuming the drive meets SATA-IO specifications, but we were cautioned not
to make this assumption and as indicated, contact the drive's manufacturerer
for verification.
2. The motherboard must support hot-plugging capability, i.e., its SATA
controller must provide hot-plugging support.
One other consideration...
SATA native hot plug as defined by the specification requires the use of the
15-pin SATA power connector, *not* the 4-pin Molex power plug commonly used
to connect IDE devices and frequently found on SATA HDs alongside the SATA
power connector. Furthermore, the specification also calls for a requirement
that the power signal cables be connected/disconnected *simultaneously* in
order for native SATA hot plugging to be supported. (In our case, we
accomplish this by mounting the external SATA HDs in the removable
tray/caddy in mobile racks so a simple push or pull on the removable tray's
handle simultaneously connects/disconnects both the power/signal cables.)
I have to admit that every SATA-IO HD we've worked with for nearly a year
now (WD, Hitachi, Samsung, and Seagate, all SATA-IO drives) has proven to be
hot-pluggable. I would add that in many instances while experimenting with
the hot-plugging capability of the afore-mentioned SATA drives while they
were connected as external devices, we've connected/disconnected the drives
without regard to any simultaneous connection or disconnection of the data &
power connectors and we suffered no ill effects that we're aware of in terms
of data loss/corruption or damage to the drives. At least none to date. Even
in cases where the SATA HD received its power through the Molex plug we
didn't run into any problems, but we really did not do extensive testing
with that configuration. In nearly every case power was applied to the SATA
HD though its 15-pin power connector.
Anna
