simultaneous copy to multiple media

[Claudio Grondi]

> Try this:
>   http://mastermind.com.pl/multicopy/
>
> This is small tool I've wrote, that does use large memory buffers with
> asynchronous I/O to copy file.

Thank you!
This (with a drawback of blocking the entire system) does it!
( dzieñ dobry i dziêkujê za t± konstruktywn± odpowied¼
na moje pytanie )

At least I know, that it works and you explain how it works,
so I am now quite sure, that it will be also possible to have
a Python tool which does the same thing.
This way the discussion going towards driver hacking for
the USB access was in my case just the wrong way, but
anyway, thanks also for that to the contributors, because it
sharpened my understanding of USB.

Here my current test results on my Windows 2000 system
with a 2.8 GHz P4 CPU and two 5 1/4" IDE-USB 2.0 casings
(I have got from http://www.computeruniverse.net/ a German
online shop, article no.: 90052509)
by the way:
  does someone know an IDE-USB case able
  to perform data transfer faster than the
  max. 20 MByte/s I experience with one of my
  another IDE-USB 5 1/4" casings?
?
) :
Single file copy:
  USB-1 to USB-2 = 11 MB/s, max. 70% CPU
  USB-2 to USB-1 = 11 MB/s, max. 70% CPU
  E-IDE to USB-1 = 12 MB/s, max. 70% CPU (first  time)
  E-IDE to USB-1 = 13 MB/s, max. 70% CPU (second time same file)
  E-IDE to E-IDE  = max. 45 MB/s  (two physical drives)

Simultaneous file copy:
  USB-1 to USB-2 =  5 MB/s
  USB-2 to USB-1 =  7 MB/s
                   -------
                   12 MB/s, max. 80% CPU

Simultaneous file copy using
http://mastermind.com.pl/multicopy/release/1.0.0/multicopy.exe :
  E-IDE to USB-1 = 10 MB/s
  E-IDE to USB-2 = 10 MB/s
                   -------
                   20 MB/s, unknown CPU load (1)

(1) work with the PC during copying not possible,
  system "hangs" from 5 to 15 seconds between
  e.g. displaying current system time (with
Windows clock).

>From my point of view this thread has reached
its end (I have a solution I can live with), except if
someone would like to contribute or point to a
better multicopy.exe which does not block the system
or best to contribute or point to a _Python_ script or
module which is able to find out the optimal buffer
size for copying on the
current system (and the best way of copying files),
so that after this information is saved in an .INI file
the tool is best adopted to the system it works on.

I am quite sure, that there is a perfect ready-to-use
solution out there (up to now I just only failed to find
one by Googling, e.g. the tee.exe provided by
http://unxutils.sourceforge.net/ doesn't work with
large files at all), so please don't hesitate to provide
it, so, that I don't need to "reinvent the wheel".

Claudio

"Jacek Trzmiel" <sc0rp at hot.pl> schrieb im Newsbeitrag
news:mailman.661.1111358610.1799.python-list at python.org...
>
> Claudio Grondi wrote:
> > I am on a Widows 2000 box using the NTFS file system.
> > Both up to now suggested approaches as
> > - tee.exe (where I used the http://david.tribble.com/dos/tee.exe
> > DOS-port with redirecting stdout to NULL) and
> > - parallel copy (hoping caching does the job) are by far
> > slower than the consecutive copy:
> >   single copy speed 12-15 MByte/s
> >     which gives effectively
> >       6-7 MByte/s,
> >   tee.exe or twice copy in parallel
> >       1-3 MByte/s.
> >
> > Any other suggestions except writing an own
> > optimised version of tee.exe
>
> Try this:
>   http://mastermind.com.pl/multicopy/
>
> This is small tool I've wrote, that does use large memory buffers with
> asynchronous I/O to copy file.
>
> Following command:
>   multicopy c:\testfile d:\testfile e:\testfile f:\testfile
> will copy c:\testfile to d, e and f disks.
>
> With four separate IDE disks I can copy file at about 30MB/s, which
> means 120MB/s total I/O.  You can give it a try, but I don't know if it
> will work fast with USB drives.
>
> HTH,
> sc0rp.