According to the paper <http://www.mewburn.net/luke/papers/build.sh.pdf>
let's use the terms `build host', `host' and `target'. On mag 03 8:30, Greg Troxel wrote: > I keep forgetting this and having to page it in, but a big concept is > that you can share userland among systems built for the same CPU type > but that are different kinds of computers. Basically MACHINE describes > the computer and MACHINE_ARCH the CPU. It may be helpful to read > build.sh. I thought it was the opposite: a userland shared by several MACHINEs of the same type but different CPUs... MACHINE is defined in the paper as a platform (par. 5.1). Intuitively, yes, MACHINE seems related to a whole computer (so, a collection of hardware devices with its standards and conventions) and MACHINE_ARCH is somewhat more specific, being related to a specific CPU, but MACHINE is still a somewhat blurry element to me. I scrolled the whole build.sh searching for the string MACHINE, but (at least at a first glance) I didn't find something new. > The tooldir is a prefix that has bin/lib and so on, which has programs > that run on the build host, and are cross for targets. > > There is also an obj dir for building the cross tools, usually the tools > subdir within the objdir. This is the exact fact which confuses me. I tried to understand this as follows (but I'm not sure it's right and the par. 5.5 in the paper did not shed a light). There are two different kinds of tools: 1. The ones in obj_dir/tools, which are the result of the building of /usr/src/tools. These are the tools used by the `build host' to build the second type of tools, the toolchain. 2. The ones in obj_dir/tooldir.NetBSD-9.99.81-amd64, which are the actual toolchain. They are used by the `host' to build the sourcecode (kernel and/or userland) for the `target' system. > -u basically means "just run make, and don't clean first", > operationally. This only works if the makefile rules are correct and > nothing has changed outside the scope of what make copes with. > > If you have changed a few lines of code, -u almost always works. > > If you did cvs update along netbsd-9, it is highly likely that -u will > work. > > If you updated along current, it often works. The shorter the time > period, the more likely. Ok! This is straght and simple. Thank you! Rocky
