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Posts: 4 | Thanked: 0 times | Joined on Nov 2008
#1
I recently bought an n800 and I've been playing with it a bit...

I have the latest diablo on it and I installed ssh-server from the repository. (with public key authentication set-up )

It's nice to have a a remote access on the device and I though I might use it to transfer some files. I though it might be more using USB too.

The only problem I had is speed. At first I only managed to get about 300KB/s though SSH using nautilus. (I am using Ubuntu 8.10 on my computer).
Then I managed to get a pretty good 800KB/S constant though "scp" using the command line. No idea why there was such a difference...

So it's working ok but I was wondering if I could get it even quicker... not sure if it's the tablet's wifi that's the limiting factor or if it's the CPU speed.
I tried transfering from a shared samba folder using the file manager build into the n800 but it wasn't any better
(more than 40s for 19MB)

Of course the wireless router could also play a role but it's really near the tablet and I am not using the wifi otherwise.

So I am asking what are your experiences with the wifi speed and file transfer ? I am also interested to know if the wifi power saving play a big role ?
 
Posts: 503 | Thanked: 267 times | Joined on Jul 2006 @ Helsinki
#2
You may want to try mounting sshfs: https://help.ubuntu.com/community/SSHFS
And changing encryption to blowfish makes ssh a bit faster.

Also you may want to search the forum for similar topics (there are several of them) to get additional information.
 
speculatrix's Avatar
Posts: 880 | Thanked: 264 times | Joined on Feb 2007 @ Cambridge, UK
#3
can you change encryption to just "DES" rather than 3des or blowfish? that would be even faster!

in theory with some ssh clients and servers you can even say encryption none!
 
Posts: 4 | Thanked: 0 times | Joined on Nov 2008
#4
I try using blowfish with SCP but it didn't seem to make much of a difference.

Serge> thx for the SSHFS link. Didn't think about mounting it. It work fine and it's at lest the same speed as SCP.
I just hope nautilus will no go too crazy when the ssh server is not accessible. I never had a too good experience with nautilus, a bit slow at time and crash too often (well, far from all the time but still too much for a file browser IMO)

I didn't think you could turn encryption off on ssh (!).
DES should be usable using version 1 from the protocol (I guess you can have to enable that on the server as it's not secure), so I might try it out if I have some time.
 
speculatrix's Avatar
Posts: 880 | Thanked: 264 times | Joined on Feb 2007 @ Cambridge, UK
#5
doing a quick test reveals that my linux desktop and tablet will only allow use of 3des, blowfish and arcfour ciphers.
when I copy, measuring the duration, thus:
$ time scp -c arcfour /tmp/100M user@10.0.0.180:/dev/null

I find that the speed reported drops off.

Times:
default = 2m41s
blowfish = 2m42s
3des = 5m52
arcfour = 2m44s

I couldn't get des, cast, aes128/256, or twofish128/192/256 to work.

my guess is that the default encryption means that the wifi is the limiting factor as only 3des slowed things down.

--edit-- P.S. This was to/from an Apple Airport Extreme running in a/b/g compatibility mode, bridged to a gigabit switched LAN. Times were, in case my quoted command line didn't make it clear, for copying 100MiB, so 2m41s means 621KiB/s
p.s.2. I had powersave on.

Last edited by speculatrix; 2008-11-06 at 21:38.
 
gultig's Avatar
Posts: 148 | Thanked: 5 times | Joined on Nov 2005 @ Stimutax, AZ
#6
Just for comparison, transferring with wget from a local web server tops out at about 800 KB/sec for me. The cpu never tops out doing this (unlike when you try to download from the browser)
 
Posts: 4 | Thanked: 0 times | Joined on Nov 2008
#7
Some test result.

Look like the wifi is the limiting factor after all.
Well around 800KB/s is still decent for a Internet tablet... I prefer the wifi being optimise for battery life and range rather than throughout. So maybe that's the price to pay.

I am going to use USB for big file transfers (got a 16GB card now!) but otherwise SSH is still really practical.
 
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