trjcat should release the memory again after checking the first frame of all files.
trjcat has memory error when joining 28,000 single-frame .xtc files.
Roland suggests that "the memory isn't freed correctly. read_first_frame is allocating the memory for one frame but in most cases it isn't freed. Thus you only see this error with many small files."
David suggests that "The program reads the first frame of all files, and since we roughly have three times compression from xtc to float your figures of 4 vs. 11
Gb. match perfect."
Berk and David pointed out that I could use cat or script the trjcat to go in 10 steps -- if the memory issue can not be dealt with easily, perhaps trjcat could issue an instructive warning message that the user should try these.
original post: http://lists.gromacs.org/pipermail/gmx-users/2010-October/054788.html and there are followups within 24 hours also on the mailing list