i wonder why no one else has reported this? i certainly don't see it under windows, so it must be unix-specific. the newline business vaguely suggests pty lossage. stephen, can you tell me when 21.1 branched off? i.e. how far back do i have to look in the changelog entries? going back from 21.4.6 i tentatively see two possible things that stand out: 2000-09-27 Martin Buchholz <martin(a)xemacs.org&gt; Big signal/process handling overhaul. Bugs fixed: 1998-02-28 Kirill M. Katsnelson <kkm(a)kis.ru&gt; [process abstraction] although i don't know if the latter is too old, and the problem could easily be elsewhere entirely. greg, it's not clear that finding a better reproduction scheme would help since this may be linux- or even red-hat-7.3-specific. what *would* help is if you were willing to retrieve some old versions to try and figure out when this happened. cvs lets you check out by date, and if you could do a binary search by date -- even just a few iterations -- between the 21.4.6 release date and the 21.1 branch-off point to narrow down when the bug appeared, it would be a *huge* help. ben ----- Original Message ----- Hi, In all of 21.4.6, 21.4.12, and 21.5-b11, I see a serious bug in capturing the process output in pcl-cvs. Running "xemacs -vanilla" if I run M-x cvs-examine in a CVS checkout directory (cvs is using the :ext: method if that matters) then hit "=" to diff a file with many hundred or thousand lines of changes, there will typically be (4096 + offset to next newline) byte chunks missing in the diff output starting at byte offsets that are multiples of 4096. The bug did not exist in 21.1.9, even running the same exact version of pcl-cvs. The problem is much worse when the machine is loaded. I am running RH 7.3 on a dual 2.8GHz P4 box with 4Gb ram. I am trying to isolate this to a simple reproducer, but wanted to send this out now in case this report is enough for whoever has been hacking on the subprocess code since the 21.1 days to figure out the bug. thanks greg ----- Original Message ----- From: "Stephen J. Turnbull" <stephen(a)xemacs.org&gt; To: <ben(a)xemacs.org&gt; Sent: Wednesday, March 12, 2003 6:45 PM Subject: [gak(a)klanderman.net (Greg Klanderman)] serious subprocess output bug in 21.4, 21.5 --------------------------------------------------------------------------------