Using FTP system command(Win XP)

[Philippe Bruyant]

Hello experts,
I have downloaded FTP_with_the_Windows_utility.llb
to transfer files from a Linux system to a PC (Win XP)
using LabView 7 Express. It works by making a system call to the ftp program installed on the PC ("System Exec.vi"). It works, but it seems to be quite slow. The FTP program tells me that the transfer was done at a 500kilobytes/sec rate (on a 10Mbits LAN), but it takes 200ms to actually download a 5kb .jpg image. Am I doing something wrong, or are the system calls slow ?
Thanks!
Phil

[Zvezdana S.]

Phil,
You are not doing anything wrong. The FTP transfer is not as fast as TCP/IP.
Making system calls additionaly slows down this transfer.
Here is another thread I found on the similar topic. The example attached in that thread uses TCP/IP, so it may be faster.
LabVIEW ftp Problem

Zvezdana S.
National Instruments

[Kevin Valentine]

On Thu, 22 Jan 2004 11:46:00 -0600, Zvezdana S. wrote:

> Phil,
> You are not doing anything wrong. The FTP transfer is not as fast as
> TCP/IP.
> Making system calls additionaly slows down this transfer. Here is
> another thread I found on the similar topic. The example attached in
> that thread uses TCP/IP, so it may be faster.
ftp Problem
>
> Zvezdana S.
> National Instruments

Cool, that was my example! I'm glad it's getting circulated around.

For a more updated version of it, go to the OpenG site:
http://openg.org/tiki/tiki-index.php?page=OpenG+Internet+Connectivity+Tools

- Kev
in

[Philippe Bruyant]

Thank you Zvezdana!
Actually, I found a way to increase the rate:
I have 40 5kB files to transfer. It takes about 8s
to do that. If I concatenate the 40 files (using the
Unix command cat) in one single 200kB file, it takes 250 ms to transfer it! It seems also that slowness is not related to LabView: If I transfer files, using WS_FTP or even the ftp "DOS" system command, without LabView, it is much faster to transfer one 200kB file than 40 5kB files.
Phil