Installing hosted Inferno from source Overview Like the native kernels emu relies on several auxil- iary libraries (the source of which it often shares with the native kernels). Emu itself is built by the mkfile in the emu subdirectory containing the platform-specific source for the host platform. Each library has its own mkfile; the various components are made in the right order by the mkfile at the root of the Inferno tree. The mkfile for each platform will also invoke mk recursively to make the appropriate libraries for a given configuration. The Unix emu variant generally is covered by `POSIX' (with common extensions) but each Unix port has one file that differs considerably for each port, namely emu/platform/os.c, the differences corresponding to the dif- ferent ways under Unix of implementing kernel-scheduled threads efficiently. There are working emu versions for FreeBSD/386, Irix/mips, Linux/386, NetBSD/386, MacOSX/386, MacOSX/power, Plan 9, Solaris/sparc, and Windows (NT, 2000 and Explorer plug-in). Each platform typically uses mechanisms specific to the host operating system to implement Inferno's internal thread/process structure. POSIX threads have often been found to be insufficient (poorly implemented) on some plat- forms, and if so are avoided. See kproc in emu/*/os.c. Source is included for ports to HP/UX (S800 architec- ture), Solaris/386, and Unixware, in case someone wishes to take them up now, but we have not determined their fitness. The Plan 9 hosted implementation is unusual in that it supports several processor types: 386, mips, power (Power PC) and sparc. Furthermore, all versions of emu can be built on any processor type, in the usual way for Plan 9. Otherwise, as distributed, emu for a platform can only be built when running on that platform. One unusual variant makes the whole of Inferno a plug- in for Microsoft's Internet Explorer, giving the same envi- ronment for Inferno applications running in an HTML page as is provided by hosted or native Inferno. That is, there is not a distinct `applet' environment with special programming interfaces. The source for the various plug-in components is found in /tools/plugin and /usr/internet within the Inferno tree; they use the version of emu defined by the configuration file /emu/Nt/ie. Build steps All the libraries and executables can be built in a tree containing only the source code. To do that for a sup- ported variant of hosted Inferno, on Unix or Plan 9, do the following in the root of the Inferno tree: 1 Edit mkconfig to reflect your host environment, specifically ROOT (which must be an absolute path name), SYSHOST and OBJTYPE. The comments in the file should help you choose. 2 Run makemk.sh to rebuild the mk command, which is used to build everything else. 3 Set PATH (or path on Plan 9) to include the bin directory for the platform, which will now contain the mk binary just built. On Unix, export PATH. 4 Then mk nuke to remove any extraneous object files. 5 Finally, mk install to create and install the libraries, limbo compiler, emu for hosted Inferno, and auxiliary commands. The rules do that in an order that ensures that the commands or libraries needed by a later stage are built and installed first. (Note that a plain mk will not suffice, because it does not put the results in the search path.) Doing something similar on Windows or Plan 9 currently requires the executable for mk to be available in the search path, since there is no equivalent of makemk.sh. Otherwise the procedure is the same. On Plan 9, of course, the host system's normal version of mk should be adequate.