Originally Posted by
Smacca
I really shouldn't quote this, but the question was raised in the field trial. Here's what the head UEC technician reckons:
1. The usb port on the back of the DSD4121 will not provide enough current for
the 2.5" drives we have tested to spin up. The startup current is typically
over 500mA. Most PC's have biefier power supplies and can handle this spike for
long enough for the drive to spin up. The 4121 will not provide this current
long enough for the drive to spin up. The 4121 is already past it's design
phase and already deployed so changing the hardware is not an option. There is
no intention to specifically limit the box to 3.5" drives, and if a low power
2.5" drive works the box will accept it. Bus powered drives will however not be
officially supported. You will notice that most 2.5" drives come with two usb
ports for this very reason. The 4121 also does not have 2 USB ports so that
option is not open to us either.
2. With regard to flash drives we have taken the stance that these do not
provide the reliability in terms of sustained writes to allow them to be used
as a PVR. While it will appear to work just fine, remember that each block in a
flash stick can onyl be written to a finite number of times before it is marked
as bad and no longer usable. The primary function of the PVR functionality will
be to pause and rewind live TV. In order to do this it is required that the
disk is always being written to. In a flash device this could mean that people
who do not power their boxes after viewing, will have video being streamed to
their flash disk all day and night which will ultimatly end up in the disk
being used up. Obviously, to most users who dont understand the technological
limitations, this will be percieved as the box breaking the memory stick.
Because of this we have decided that supporting flash based drives is not
feasible for PVR functionality. You will notice by looking on the market that
even the high end PVR products do not use SSD hard drives yet even though they
are low power, low heat devices. This, and the cost, is the reason for that.
Bookmarks