[Wolves] Two quick questions:

[Adam Sweet]

--- Wayne Morris <wayne at machx.co.uk> wrote:
> Wayne Morris wrote:
> 
> >>
> > Ah, nice one Ron and Stuart.
> > I have also found WinSCP, which has a graphical
> two window interface 
> > for ftp like movement.
> 
> I'm getting some lousy transfer rates, two processes
> runnng, both 
> copying at about 1 Mb/sec each.
> Is this a SCP thing or my hardware (the target pc is
> on a wireless 
> connection (54mb) and data is going to a USB
> harddrive.
> (I'm copying 30 gb of data, so its going to take
> another 6 hours at this 
> speed!)

1MB per second isn't unreasonable. First of all, I
don't know if this is just your typing short hand, the
difference between MB and Mb is distinct. Mb is
megabits, MB is megabytes. A byte is 8 bits, a
megabyte is 1024 Mega bits.

On a 10 megabit connection you will get roughly 800
kilobytes per second without any other machines
talking on the network (network transfers add a bit at
each end of a byte to mark the start and finish of the
byte so that transfer errors can be recognised). On a
54g connection you would get at best about 4.5
megabytes per second (not a scientific
calculation...).

On top of that, you are using an encrypted transfer
protocol which requires CPU intensive work at each
end. If you are using WEP encryption too, this also
requires further CPU work at each end, or at least on
your access point and sending machine. That adds to
the transfer overhead, as you can only send data as
fast as you can encrypt and decrypt it.

There is an SSH option for compression, I don't know
what it is though, or how to set it up for a Linux to
Windows transfer.

Another overhead is the usb disk write speed and the
speed of the USB bus itself. USB 1 can transfer at 1.5
megabits per second, 1.1 can transfer at 12 megabits
per second (about 1 megabyte like you're seeing), USB2
can transfer at 480 megabits per second. Add to that
the low write speed of a USB disk.

Most likely though is that if you're using USB 1.1,
thats your bottleneck.

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