Jim Meyering wrote: > Pádraig Brady <[EMAIL PROTECTED]> wrote: >> I was thinking it would be useful to >> add an option to dd to tell it to >> instruct the OS not to cache the data. > > I like the idea, even if it works only with very recent Linux > kernels.
It's not that new. It's in since 2.5.60 according to the man page, and I verified the code is in 2.6.0 Also it uses a posix interface, so I presume this is available elsewhere. > >> Personally I use dd to move large files like disc images etc. >> around, and I know I will not need the file cached. >> >> A very quick example patch which has only >> been tested on linux is attached. >> >> Do you think this is required? >> Do you think this is the right interface? > > There are two separate sets of data to which we > might want to apply such an optimization: input and output. > > So how about an interface that lets the user disable caching on > either or both? E.g., no-i-cache no-o-cache. > I find the "-"-less options far less readable. > Actually, I prefer the even longer names: > input-cache-disable > output-cache-disable > > nocache could still be an alias for the combination. I considered this, but thought you wouldn't need this granularity. But thinking more about it I think you're right. If we want to control input and output separately perhaps we should use flags. So we have: iflag=nocache and oflag=nocache The usual case where we want to do the same on both could be handled with flag=nocache One can't specify both [io]flag=FLAGS with flag=FLAGS at present, but I think that should be supported anyway. thanks, Pádraig. _______________________________________________ Bug-coreutils mailing list [email protected] http://lists.gnu.org/mailman/listinfo/bug-coreutils
