From: Alexander A. Vakhrushev (
Date: Tue Oct 07 2008 - 12:03:16 CDT


It seems to me, that there were no such problems in v1.8.5, so I'll
recheck to find possible solution.

2008/10/7 John Stone <>:
> Alexander,
> On Sat, Oct 04, 2008 at 08:55:52AM +0500, Alexander A. Vakhrushev wrote:
> [...]
>> I have the following question: Windows version of VMD does not allow
>> to load DCD trajectory file while it is being downloaded from remote
>> host (in other words when file is of incomplete size). When I stop
>> download even it was not finished everything goes OK. Linux version
>> does not has such behaviour. Would you suggest any solutions?
> The Windows version of the DCD plugin uses the Win32 binary file I/O
> APIs, which have different limitations and semantics than the
> read/write/seek calls on Unix. I believe the likely source of problems
> is the code we're forced to use on Windows to determine the size of
> large files (files larger than 4GB) since the Windows implementation of
> the normal libc calls is not capable of dealing with such large files:
> #if defined(_MSC_VER) && defined(FASTIO_NATIVEWIN32)
> /* the stat() call is not 64-bit savvy on Windows */
> /* so we have to use the fastio fseek/ftell routines for this */
> /* until we add a portable filesize routine for this purpose */
> fio_fseek(dcd->fd, 0, FIO_SEEK_END); /* seek to end of file */
> filesize = fio_ftell(dcd->fd);
> fio_fseek(dcd->fd, curpos, FIO_SEEK_SET); /* return to end of header */
> #else
> filesize = stbuf.st_size; /* this works ok on Unix machines */
> #endif
> You could try writing another piece of code to query the file size
> that behaves better with files that are in the process of being
> appended to, but it's really somewhat of a questionable scenario to
> attempt to load files that are in the process of being updated since
> OSes handle these things a bit differently.
> Cheers,
> John Stone
> --
> NIH Resource for Macromolecular Modeling and Bioinformatics
> Beckman Institute for Advanced Science and Technology
> University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
> Email: Phone: 217-244-3349
> WWW: Fax: 217-244-6078

Best regards,
Dr. Alexander Vakhrushev
Institute of Applied Mechanics
Dep. of Mech. and Phys.-Chem.
of heterogeneous media
UB of Russian Academy of Sciences
34 T. Baramzinoy St.
Izhevsk, Russia 426067
С уважением,
    Вахрушев Александр Александрович
к.ф.-м.н., с.н.с.
Институт прикладной механики
Уральского Отделения
Российской Академии Наук
426067, г. Ижевск
ул. Т. Барамзиной 34