J
John John (MVP)
It works the same way with XP Home as it does with XP Pro. The head
parking business along with the Park command is stuff for the museum of
antiquities. As Bob said in another post, voice coil hard disks are
"self-parking", the actuator is spring loaded, you need power to
"unpark" the heads and as soon as the power is removed the heads are
"sprung" back to the parked position. Sort of the same as air brakes on
a large tractor truck, you need air pressure to unlock the brakes, as
soon as air pressure is lost (if an air hose breaks) the brakes
automatically lock and the truck can't move. This is another passage
from a Microsoft training book/kit:
parking business along with the Park command is stuff for the museum of
antiquities. As Bob said in another post, voice coil hard disks are
"self-parking", the actuator is spring loaded, you need power to
"unpark" the heads and as soon as the power is removed the heads are
"sprung" back to the parked position. Sort of the same as air brakes on
a large tractor truck, you need air pressure to unlock the brakes, as
soon as air pressure is lost (if an air hose breaks) the brakes
automatically lock and the truck can't move. This is another passage
from a Microsoft training book/kit:
Voice coil hard disk drives offer several advantages:
* The lack of mechanical interface between the motor and the
actuator arm provides consistent positioning accuracy.
* When the drive is shut down (the power is removed from the coil),
the actuator arm, which is spring-loaded, moves back to its initial
position, thus eliminating the need to park the head. In a sense, these
drives are self-parking.
[end quote]
http://www.microsoft.com/mspress/books/sampchap/4433.aspx#11
John
If you can, please explain. When I do a backup to my external drive and it
finishes, I shut down my backup program.
I use a Seagate HD. At this point, I click SRH and the HD sounds as though
the heads are retracting. I then shut the power off on the HD. I am not
using XP Pro.
No, it ensures that all the data is flushed to the disk.
When removing a device from a bus that supports hot plugging, if the
Safely Remove Hardware icon appears in the notification area, use the
Safely Remove Hardware application as explained later to ensure a safe
removal of hardware from the system. The Safely Remove Hardware
application informs Windows that the user intends to remove a device. This
gives Windows an opportunity to prepare for the removal by taking steps
such as halting data transfers to the device and unloading device drivers.
When hardware is removed from a running system without using the Safely
Remove Hardware application, it is often referred to as surprise removal
because the operating system is not notified in advance of the removal.
Surprise removal is particularly a concern for storage devices for which
write caching is enabled, because when such devices are surprise removed,
data loss or corruption might occur. To reduce the likelihood of data loss
or corruption as a result of surprise removal of consumer-oriented storage
devices, Windows XP Professional disables write caching by default for
these devices (such as cameras that include IEEE 1394 or USB storage,
small form factor storage devices such as compact flash, and so on). While
write caching policy addresses this particular issue, it is recommended
that users continue to use the Safely Remove Hardware application when it
appears in the notification area. Also, disabling write caching might slow
the performance of consumer-oriented storage devices.
[end quote]
http://technet.microsoft.com/en-us/library/bb457107.aspx
Unknown wrote:
That is precisely what SRH does, makes sure heads are retracted. .
Same place they are after power fails, retracted.
Unknown wrote:
Where are heads when HD is being shipped? Parked???
Probably flushing the cache. Parking heads isn't a "command" that I
believe applies to voice coil head actuators.
Unknown wrote:
You run SRH BEFORE powering off the external drive.
I don't buy the "parking heads" thing either. Parking the heads is
an "old school" thing. Modern drives park the head when powered off.
Sounds like urban legend to me.
The "Safely Remove Hardware" utility that sits in the System
Tray.... does anyone use that?
I have never used it. But recently a couple things came up that
made me wonder if I should be using it. A couple weeks ago I was
at someone's laptop and I had plugged in and later removed my USB
pen drive. He commented that I should be using the SRH utility
"because he had burned up a USB pen drive by *not* using it". I
have several of those drives and have never had an issue... and
like I said, I've never used that utility to disconnect a USB
device before unplugging it.
But today I had unplugged a Maxtor OneTouch external USB drive -
and did not use the SRH utility. When I plugged a different Maxtor
OneTouch drive into the same machine, Windows didn't recognize it.
I tried several different USB ports... same thing. So I used the
SRH utility to *Stop* the USB mass storage device in there. Then I
plugged the drive in, and Windows recognized it.
Just wondering what other people say about this utility, and if you
use it. I've always been under the impression USB devices were
hot-swappable and didn't require any user-intervention, such as
using that utility
TIA
Concur with most responses, except the parking heads response.
While using SRH, I've noticed that sometimes something must be
occurring even though the activity light is off on the external
enclosure. SRH says something is still accessing, to try again
later. Usually, an immediate retry of SRH allows removal. Seen this
with both Firewire and USB2 enclosures for ide hard drives.
An oddity I've noticed about the policies tab for the hard drive
within the enclosure. An old Firewire only enclosure I have uses
the non-cache type selection per windows installation of same. The
newer USB/Firewire combo enclosure for ide drives use the cached
type that requires SRH. Don't matter if USB or Firewire connected.