UNIX for Dummies Questions & Answers

Maybe
uname -S newname

uname -S does set hostname to newname.But it is not consistant.It will again change to previous name after reboot.

So you need to add that command to the startup scripts that get executed at reboot time. Another approach is to rebuild the kernel with the new hostname builtin. But I'm not sure how to do that on an old NCR box. I would try to find where the old hostname is set by doing:
cd /etc
grep oldname *
it may be as simple as replacing it there. (Could also be in a subdirectory of /etc. Especially check for /etc/conf) But you may find it in a file which is intended as input to the kernel build process (possibly called /etc/system or /etc/master I think) and it won't take effect until you rebuild the kernel. Or that file may be read by the kernel at reboot time... I'm just not sure how your system works. I think that the NCR's had a system admin tool called va which is a text based menu system. If you can find that, you might look for a change hostname option or a kernel rebuild option. Note that what you are calling "hostname" is probably called "system name" or something like that.

I worked on an NCR box circa 1990 but it was an NCR box and not a Pentium. So I'm not too sure of what system you have or precisely how it works. Even if you had an old Tower 800, it's been almost 20 years since I've seen one and I have forgotten most of it. So take my comments witha grain of salt.