[comp.unix.wizards] Ulimit on V/68

kent@happym.wa.com (Kent Forschmiedt) (08/31/89)

 [Chris Lewis is running B News 2.11 Patchlevel 14, running on V/68 
  R2V?; it breaks its history file;  David Beckemeyer suggests that the 
  problem is ulimit, then suggests putting a large ulimit in the 
  crontab line.] 

Since V/68 R2 has private crontabs, and Lewis' news is hopefully not 
running as root, a ulimit command in the crontab won't work.  Happym is 
running V/68 R2V2.3, and the default ulimit is 1MByte.  Rather silly.  
Fortunately, V/68 includes MAXULIMIT in its tunable parameters. Here is 
how you fix it (this doesn't require source, only the standard link kit 
- you have it unless you deleted it): 

$ su
# cd /usr/src/uts/m68k
# ed cf/cmaster
/MAXULIM/s/[0-9]*$/32768/
w
q
# make vme131_?  # see below...

There are several configurations, vme131_[1-n], depending on when you
bought your system and things.  The differences are mainly which drivers
are included and how many devices to make space for in the disk and
serial port drivers.  If you are running an off the shelf configuration,
it is probably 1 [40M drive(s)], 2 [40M drives plus SMD device], 3 [70M
drive(s)], or 6 [70M + SMD].  There is a line in each kernel's commands
something like this:

		DFOPTS="-DM320DK0=WD70 -DM320DK1=WD70 -DM320DK4=WD70
		 -DM320DK5=WD70 -DM320=2 -DM350=1 -DDBUF=1 -DCNFIG=3"

This one says that disks 0, 1, 4 and 5 are 70M winchesters, there are 2 
MVME320 disk controllers, 1 MVME350 tape controller, and some other 
things you probably shouldn't mess with.  The SMD controller is MVME360,
so if you have one you should choose a configuration with -DM360=1 in it.

There are lots of other things that you can tweak, although some of them
are dangerous.  You probably will want to increase MAXPMEM if you have
more than 2M of RAM in your system.
-- 
 kent@happym.wa.com, uunet!nwnexus!happym!kent, Happy Man Corp 206-282-9598

kent@happym.wa.com (Kent Forschmiedt) (08/31/89)

In article <840@happym.wa.com> I explained some about changing V/68 
kernel parameters and linking the kernel (a similar process is used by 
many vendors' versions).  I forgot to mention how to install it. 

I don't know if you can just "cp unix131_3 /unix" - don't try it.

Instead:

# cp unix131_3 /newunix     # The bootloader won't handle uppercase letters!!!
# chmod o-w /newunix		# but it needn't be +x
# cd /
# /etc/shutdown
 .
 .
 .
Hit the reset button on the machine...
130Bug>bo,,newunix
 .
 .
 .
If it works, everthing will come up and look normal.  If it doesn't, reboot
with "bo" to use your old kernel.

Different distributions have somewhat different /stand directories.  My
system keeps its kernels in /stand/m68k/kernels.  Anyway, find your
"kernels" directory...

# cd /
# mv unix oldunix
# ln newunix /stand/m68k/kernels
# ln newunix unix
# ln unix /stand

Keep all of your kernels in /stand/m68k/kernels, keep a link to a 
trusted one and experimental one(s) in /.  You needn't name the kernel 
/unix for the bootloader to work, since you can tell it any name you 
want to, but ps(1) won't work unless /unix is identical to the running 
kernel.  I forget why there is supposed to be a link in /stand - maybe 
some utility expects to find it there. 

Other notes... 
If you are worried that your new kernel might blow up (especially if you 
have installed a new driver), change the initdefault entry in 
/etc/inittab to bring the system up in "s" single user mode instead of 
"2" multiuser. It will come up with no getty's and no filesystems 
mounted (except the root).  You can then goof around with it and try to 
break it without too many variables and risk to your filesystems. 
-- 
 kent@happym.wa.com, uunet!nwnexus!happym!kent, Happy Man Corp 206-282-9598