[mythtv-users] 1TB USB $225 US

[David Brodbeck]

On Feb 11, 2008, at 11:27 AM, John Drescher wrote:
> I believe I have got 980Mbit/s (using netperf) between 3 year old AMD
> TYAN motherboards and a netgear 24 or 48 port gigabit switch with that
> was in use. But this is much lower (300 to 700Mbit) if you connect to
> systems with GBit PCI cards (stay away from realtek).

Yeah, I've gotten very close to the theoretical max using servers with  
on-board Broadcom Tigon 3 chipsets, too.

Blasting bits out at that speed isn't that hard.  But reading/writing  
bits to/from a disk *and* blasting them out at the same time is much  
tougher.  The system bus can easily become a limiting factor,  
especially if software RAID is in use. That doesn't mean Gigabit  
doesn't live up to its promises, it just means the bottleneck is  
elsewhere.

This is an old story, though.  In the days before switches you would  
almost never get more than 80% of a 10baseT network's rated speed  
unless you only had two machines on it.  Same with 10base2. :)  The  
name referred to the signaling rate, not necessarily how fast you  
could shift real bits.

I think the most egregious example was "56K" modems, which couldn't  
*ever* run more than 54K due to FCC regulations.  In real life speeds  
above 49K were rare.