There's another model. VSE, which has *roughly* the same F/V(B)/U I/O scheme as z/OS, supports FBA disks. I am not familiar with the details such as whether emulated CKD blocks span sectors.
It's pretty easy to see how TTRs and MBBCCHHRs could work: they might become logical tokens like they are for PDSEs. Alternatively, for TTRs, FBA disks could be considered to have some sort of "pseudo-track" that held 255 or 256 blocks, so a TTR could point to up to 2**24 or so blocks. A similar scheme could be made to work for MBBCCHHR. Am I wrong in my impression that now, at the actual true hardware level, all z/OS disks are in fact FBA (i.e., sectored)? Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Paul Gilmartin Sent: Wednesday, July 05, 2006 11:15 AM To: [email protected] Subject: Re: avgrec/avgblk history ? On Wed, 5 Jul 2006 12:08:58 -0500, Tom Marchant <[EMAIL PROTECTED]> wrote: > > >FBA rules. > > That depends upon how it would work. Would each block start > immediately after the last, or at the beginning of the next > physical block? What about crossing extents? How would a > PDS work, or anything else that uses TTR (or MBBCCHHR)? > I think the model for this is PDSE, which ignores the programmer's logical blocking and simply stores records. I believe it's possible ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
