Il 02/05/2012 12:50, Christian Borntraeger ha scritto: > On 02/05/12 12:25, Paolo Bonzini wrote: >> Il 02/05/2012 12:18, Christian Borntraeger ha scritto: >>> Maybe that really points to the problem that we are trying to solve here. >>> For a dasd device, there is usually a 4096 byte block size and on the host >>> these 4096 arereported via getss and getpbsz. >>> The geometry reported by the device driver is usually 15 head and 12 sectors >>> per track, but actually means 12 sectors of 4096 bytes size (a track ~ 48k). >>> >>> What I want to achieve is that the guest view is identical to the host view >>> for cyls, heads, secs, and all block sizes. >> >> I think what you want is _not_ to have the same view as the host. What >> you want is simply to have a default that is consistent with what is >> common on actual s390 disks. > > Let me put it in another way: > > I want to have these values to match the _device_ that we are passing to the > guest > because several tools and the partition detection code for a compatible disk > format > (those that can be accessed by z/OS) needs those values to work properly.
Ah, you never pass part of a disk to a guest and part of the same disk to another? > IOW the geometry for dasd devices is not an artifical number, it has some > real meaning > that has a influence on the data structures on the disk. Yes, I understood this. Paolo
