Minimum files needed to boot

[Nathan Annis]

I am using 10.2 and operating in runlevel 1. I need to know the absolute minimum number of files I needed to boot. Does anyone know this or how I could do it. Thanks.

[Pete Randall]

Nathan,

That depends on what you consider "booted". If you mean to get to runlevel 1, you might only need the kernel (/stand/vmunix) and the contents of /usr/bin. If you mean to get to multi-user mode (run level 3, usually), then you're going to need a complete root volume with /usr, /etc, /var, /stand, at least.


Pete

[Nathan Annis]

Yes, I want to boot into runlevel 1. Are all the files in /stand/vmunix and /usr/bin necessary?

[Bill Hassell]

As Pete mentioned, the minimum number of files is very dependent on what you expect once the system is booted. This project could require several days of research. You would need to define what (if any) network services you would need (telnet, ftp, rlogin, etc), whether you even need a login at at all, whether you need an editor like vi, whether you need tools to build a kernel, whether you need SAM, whether you need support for a graphics environment, printing, email, and the list goes on. Also, the vast majority of programs will use shared libraries so many of these files are necessary (/usr/lib), and most programs need /tmp and /var available.

With lots of work and loss of all connectivity over the LAN, you might get the list stripped down to a few dozen files but the usefulness of such a system would be questionable.

[Kent Ostby]

To get to single user mode, you don't need anything in /usr.

There are several files in /etc and of course what is in /stand plus root's valid shell in /sbin.

Now going above that will require /usr to be mountable and a certain number of files there.

It might also help if you could post what you are trying to accomplish since that might limit the files you have to have.

Best regards,

Kent M. Ostby

[Bill Hassell]

At run level 1, the expected behavior is that the startup script in /sbin/rc1.d will be run. In your last question, you asked about /stand...well, you can wipe out everything in /stand except for vmunix. But this would be suicide for the system because you could no longer build a new kernel nor could you boot off the previous kernel in case there was something wrong with the existing kernel. You could perform a few sysadmin tasks with /usr/bin and /usr/lib but forget about vi--it won't be there.

Is this a question about disk space, memory or what? Trying to boot with a minimum number of files sounds like a question that has another problem behind it.

[Nathan Annis]

HPUX 10.2 is the operating system used on the Navy's Aegis ships and I am part of a small team tasked to install all software via the network. There are various system constraints (both hardware, software, and administrative) that we have to deal with. To deal with both space and time constraints, in the event that we cannot install all software over the shipboard network, we need to know the smallest subset of files needed to boot in runlevel 1. Thanks for your help and I'll probably have more questions soon.

[Bill Hassell · Accepted solution]

Wow, that will be a rather significant task but the good news is that Ignite/UX is available for 10.20 (note: obsolete and unsupported). I would start with a test system and start removing files that you know are not needed. Since this system will not be creating new kernels, /stand can be trimmed as well as many of the development libraries. But the key is to approach it from a takeaway point of view. While we could recommend removing the majority of the files and directories in /usr, this may cripple your application(s). So it is more of a "what don't you need" question.

Given the environment, this is going to be a rather significant task. For instance, you may not see cut or awk running but if you remove them, several scripts and programs may stop working correctly.