How to build your own version of PicoBSD?

1. Beginning with version 0.4, PicoBSD sources are maintained as part of official FreeBSD CVS repository, so you can find them in src/release/picobsd.

2. Become root. You'll need to mount and unmount various volumes.
3. Make sure you are running kernel with support for vn(4) devices. If you run plain GENERIC (just as it was installed on your system), you'll need to recompile you kernel and reinstall it. See the appropriate entries in The Handbook (/usr/share/doc/handbook).
4. Change working directory (cd build) and run the ./build script. Select target language, size of MFS and one of pre-canned setups (personal dialup, dialin server or router-like). Details of each setup are contained in dial/, router/, isp/ and net/ directories respectively. You should at least check ${TYPE}/config/PICOBSD file to make sure it contains the drivers you want.

   You can also choose a special type called 'custom'. You'll need to supply the full path to your own custom config tree constructed exactly like one of the standard config directories. Also, you'll probably want to adjust the number of inodes on MFS - see the stage1 script and look for INODES=.

   I also recommend to adjust the ISA devices parameters to match the ones of your hardware - though PicoBSD can save the changes from UserConfig, this way it will produce smaller /kernel.config file.

5. I assume you will use 1.44MB floppy. If not, please edit the file build/stage3.
6. There are several directories which contain some sources and config files:

   	build/			main build directory; you MUST cd here!
   	dial/			config files for dialup setup
   		conf/		kernel config file
   		crunch1/	crunch of system programs
   		mfs.tree/	contains the MFS configuration
   		lang/		contains language-dependent files
   		floppy.tree/	contains the startup floppy hierarchy
   
   	isp/			config files for dialin server setup
   		...		(as above)
   	net/			config files for router-like setup
   		...		(as above)
   	tinyware/		collection of small system utilities
   	tools/			additional tools them needed during build
   

   There are no /etc/passwd nor /etc/pwd.db files on the "dial" floppy - in case of other types, they are reconstructed from /etc/master.passwd on each startup (and then put on MFS with the rest of /etc). In case of "dial" type floppy, you don't need them at all.

   NOTE: thanks to the above, the floppy is needed only during startup, and then only if you want to synchronize (possibly changed) MFS /etc with the one on the floppy. It means that you can pull off the floppy from the drive as soon as login: prompt appears. In other words, it is almost equal to read-only floppy.

7. Edit the set of installed programs.
   • Go to ${TYPE}/crunch1 directory, and edit it to suit your needs. Keep in mind that floppies aren't made of rubber... :-)
   • There are some patches included in these directories, which are applied during build process to some of the Makefiles in your /usr/src. These patches attempt to decrease the size of some programs by cutting off rarely/unlikely used parts. The patches are reversed when you do a make clean (or build/clean for that matter).

     NOTE: patches may fail to apply, if your sources are too different from the ones I used. Don't worry: they are so straightforward that you can apply them by hand.

   • In order to have a functioning system you MUST include at least /stand/init, or /stand/oinit, or /stand/sysinstall in your crunch.conf. Of course these can be your own programs... But if you install the stock /sbin/init, you also have to install some others, like sh, getty, login etc...

     This release of PicoBSD contains a small replacement for init(8), called 'oinit'. You can find it in TinyWare collection. The main building script allows you to use it instead of normal init(8). Be sure to read the oinit's docs before you decide to use it!

8. Make sure that the system you're running has /dev/[r]vn0* entries in /dev directory (if not, you can make them with 'MAKEDEV vn0'), AND that your running kernel has built-in vnode driver (there should be a line in your kernel config file stating 'pseudo-device vn xxx').
9. You'll need at least 9MB of free disk space, and free /mnt directory.
10. Do a cd build/ and fire off the ./build script. Select the build parameters or 'n' for 'no change'. If all is well, after some time (like 10-30m) you end up with a 'picobsd.bin' file in this directory.

    WARNING: make sure you don't have stale .depend files around!!! You may encounter many strange errors during build process in that case.

    If there were any errors, please execute each script by hand and try to find what causes this error. Most often this will be one of the following reasons:

    • crunchgen can't find the source directory for a program 'proggy':
      • make sure that the source directory for 'proggy' is called 'proggy', otherwise the crunchgen won't find it
      • make sure that the Makefile allows crunchgen to deduce the set of objects to build. You can manually add an OBJS= ... to the program's Makefile.
    • crunch fails to build.
      • check your system source tree for stale .depend files and/or objects (*.o)
      • see if the individual programs can be built using original Makefiles. If not, cvsup the correct sources.
    • /: write failed - file system is full
      • this one is obvious - you wanted to put too many programs on the MFS and/or the target floppy. Or, you really don't have any space left on the root partition.. :-)
      • also, you can check if the MFS size is correctly reported while it's still mounted (right after stage1 script ends).
    • the build process displays "Preparing MFS" and then silently stops. In this case check if you're running it as root, and that you run kernel with support for vn(4) devices. Also, you can add 'set -x' at hte beginning of the scripts to see exactly where they stop.
    You can also remove 2>&1 redirections from Makefiles to see the stderr.
11. Transfer this file to the floppy:

    		dd if=picobsd.bin of=/dev/rfd0
    

    (The 'build' script asks you if you want to do this.)

That's all. You're welcome to change and improve these scripts. If you stumble upon something which looks like a good idea to have it here, let me know.

If, for some reason, the scripts don't work for you at all, also let me know.

<abial@freebsd.org>