How to upgrade from 1.7.2 to 1.7.4. First, the 'setup' script that used used for a normal installation now notices that a Minix system is already present and will offer to "upgrade" it. This means that is will save the contents of /usr/ in /usr/.old/ and then install normally. So the root file system is replaced, /usr is filled with new stuff, and you can rescue some old files from /usr/.old/. If you'd rather replace the source and recompile like real programmers do, then here is the list of steps to take: Note: Things you have to do as root are marked with a # sign. The ! sign marks the actions of bin. # Replace the sources, that's /usr/include, /usr/man, and /usr/src, with the 1.7.4 sources by extracting the SYS.nn images in the normal way. (Don't forget to move or remove the 1.7.2 stuff.) ! All 1.7.4 commands can run under 1.7.2, and all 1.7.2 commands can run under 1.7.4 if BINCOMPAT and SRCCOMPAT are set to 1 in . Nothing really interesting changed in this upgrade to make things difficult. ! Move to /usr/src/lib and type 'make install'. You need new libraries for the new kernel. ! Customize /usr/include/minix/config.h to add or remove drivers. In /usr/src/tools type 'make hdboot'. The /minix file should automatically be transformed into a directory containing both the old 1.7.2 and the new 1.7.4 kernel. The newest of these two is chosen on boot. Try it. If it doesn't work then 'image=minix/old-image' is the way to recover if it fails. ! If it works then halt the system again to return to the boot monitor prompt. Now set 'rootdev' to the same value as 'ramimagedev'. If your system is a 286 then set the RAM disk size with 'ramsize' to as much as you can spare up to 512 Mb for the so-called "second level cache". (Minix-386 should have been configured with a large primary block cache.) Type 'save' to record the changes. Boot the system. ! Your system should now be running 1.7.4. Install the commands from CMD.nn and use 'make install' in /usr/src to recompile the rest of the system. # Run 'checkhier' to check your top level directory tree. It suggest commands to execute to fix descrepancies in the top level directory tree. # Compare all files in /usr/src/etc with those in /etc. Some may have changed and should be replaced. Be careful not to lose changes you have made to files in /etc.