puder (11/20/82)
This may end up generating a lot of discussion because it is so deeply engrained in the system, but I commonly see a need for it, so I have to get this off my chest. I think the WRITE permission bits on files should actually be two bits. One for MODIFY and the other for APPEND. This would be a useful distinction, especially for (spool) directories and log files. I know, this means that llss and such will have to be modified, but they have to be modified for 4.2 anyway. It is fairly obvious what APPEND without MODIFY means, but perhaps I should mention my thoughts on what MODIFY without APPEND means. It basically means that the file cannot be made larger. On a directory it would mean that files could be renamed (and deleted?) but not created. I welcome (serious) discussion of this idea, even to say that it won't work, or is misfactored, but please, no flames. Karl Puder Burroughs R & D (215)648-7555
gwyn@Brl@sri-unix (11/28/82)
From: Doug Gwyn <gwyn@Brl> Date: 27 Nov 82 0:01:46-EST (Sat) Seems reasonable to me. Note that USG UNIX now has an "open for append" mode available, as well as "open with truncation". Someone recently suggested to me that the following independent write mode bits would be useful: 1) Allow creation if not present. 2) Truncate to 0 length on open. 3) Append (all writing guaranteed at end). 4) Exclusive open.