[mythtv-users] 1TB USB $225 US

Chris Pinkham cpinkham at bc2va.org
Mon Feb 11 21:31:59 UTC 2008

* On Mon Feb 11, 2008 at 02:07:01PM -0500, Dan Ritter wrote:
> USB can come pretty close to advertised speeds, but disks can't,
> and USB doesn't handle contention by several high-bandwidth
> devices well. It's great for random input devices and small
> storage, but expecting 480Mb/s from a disk that can only push
> 150MB/s from cache and about 90MB/s from spinning iron is silly.
> The fastest Ultra320 SCSI disk, spinning at 15K RPM, has a
> maximum transfer rate of 135MB/s. 

You're mixing your bits and bytes up a little.  The USB speed you're
quoting is in bits and the hard drive figures you're quoting are
in bytes per second.

Expecting 480 Megabits/sec (ie, only 60 MegaBytes/sec) from a
drive that can push 150 MegaBytes/sec from cache or a 'measly'
90 MegaBytes/sec from the platters is not silly.


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