On Mon, 31 Dec 2012 12:18:30 -0500 (EST), Bobby Bauer wrote: > > Been reading, always a dangerous thing. > In Chapter 25. Configuring an Installed Linux on System z Instance, > I see in zipl.conf, USE_DIAG=0. In dasd.conf I see USE_DIAG=1. > What is the difference? > > Where do I find these? I don't have a USE_DIAG coded in my zipl.conf.
There are basically three ways to turn DIAG on: (1) At kernel boot time via the kernel command line options. (2) At dasd module load time via a configuration file in /etc/modprobe.d, and (3) dynamically via the /sys pseudo file system. Most distributions use the third method, via udev, either directly or indirectly (via sysconfig-hardware). > > Goggling around I also found a hit that said using USE_DIAG=1 > doesn't allow the allocation of a swap file. Hmm. Well, due to restrictions in how DIAG is handled, that may be true for some distributions, but as far as GNU/Linux itself is concerned, that is definitely NOT true. I use the DIAG driver for everything in my system, including the root file system and swap partitions. The only thing that does not use the DIAG driver is the /boot partition. zipl does not support writing out IPL records to a device which is using the DIAG driver; so I have a separate /boot partition which does not use the DIAG driver. But everything else does. You might want to read the following web page: http://users.wowway.com/~zlinuxman/diag250.htm The page is Debian-specific; so it may not match your distribution. But even if it doesn't, you may learn something useful about the DIAG driver in the process of reading it. -- .''`. Stephen Powell : :' : `. `'` `- ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
