> In theory, we could mangle the IPL code into the first > 512 bytes of a filesystem which is reserved on x86 as "partition boot > record", ...
You should thusly mangle the IPL code. :-) It doesn't break anything else to do so. > a) the disk would not be "labled" as observed by other mainframe OSes > b) this would differ from how people use Linux on other platforms > where they typically do use partitions ... The problem with mainframe labelling (the req for an IBM volser) is that it panders to the bad behaviour of a certain other mainframe op sys. Also, we're mixing labelling with partitioning. They are not the same thing, though CDL accommodates both. It is presumptuous, and increasingly incorrect, to expect that users partition everything on other platforms. In fact, there are growing numbers of cases where users/customers DO NOT partition physical media. Windows assumes partitioning (except where it is forced to know better). Too bad for Windows. z/OS assumes IBM volsers. Too bad for z/OS. This is Linux. We should be able to bypass the complexities and ... Keep It Simple. Partitioning is a layer of complexity. Where it is needed, fine. Where it is not needed, let us turn it off. -- R; <>< Rick Troth Velocity Software http://www.velocitysoftware.com/ On Wed, Jan 5, 2011 at 03:06, Carsten Otte <co...@de.ibm.com> wrote: > Quote: >> Mark is correct: one automagically created partition. Worse, there >> is no 'fdasd' or 'fdisk' management of that partition. WORSE STILL, >> you *must* put the filesystem into the "partition" (such as it is) if >> you are going to boot from this disk. A filesystem in /dev/dasdx will >> be clobbered by the first stage of the boot loader, while a filesystem >> in /dev/dasdx1 is protected by the extra 8K of padding. (12K total) > >> I checked it again this morning. The bootstrap overwrites the root > inode. > > Well the LDL disk layout basically consists of two blocks of data > (size depends on the blocksize used for formatting) > Those are being used to a) label the device and b) conatin the IPL boot > code > (channel programs). In theory, we could mangle the IPL code into the first > 512 bytes of a filesystem which is reserved on x86 as "partition boot > record", > but that'd have a couple of downsides: > a) the disk would not be "labled" as observed by other mainframe OSes > b) this would differ from how people use Linux on other platforms where > they > typically do use partitions > in front of the partition. > Note that for LDL formatted media, you may chose to put the filesystem on > the > device itself (like /dev/dasdx instead of /dev/dasdx1) for volumes that you > do not intend to boot from. > Due to the fact that for ECKD CDL media blocks on track 0 do not have the > formatted size, you cannot do the same with ECKD CDL formatted disks > (filesystem corruption would be the result). > > with kind regards > Carsten Otte > IBM Linux Technology Center / Boeblingen lab > -- > omnis enim res, quae dando non deficit, dum habetur et non datur, nondum > habetur, quomodo habenda est > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, > send email to lists...@vm.marist.edu 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/ > ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu 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/
