On Thu, 2 Aug 2012 17:00:02 -0400, Thomas David Rivers <[email protected]> wrote:
>I'm having some issues with using the OS Simulation >macros NOTE and POINT under VM/CMS. > >I've been scouring documentation to try and >discover just what the CMS differences are... > >But, at the moment, I'm trying to simply do >a BSAM OPEN (for READ)... > >Then, a NOTE to record the starting TTR of the >file... > >Then - reading the file to the end (with regular >BSAM READ+CHECK) > >Then, a POINT to return to the beginning of the file, >using the TTR retrieved from just after the OPEN >(with +1 added because the NOTE occurs after OPEN >but before any READ.) > >Then - try and READ the blocks again... > >What I'm seeing is that the NOTE returns something >that "looks like" a TTR. Then, the READs+CHECKs >occur that read the file. > >The POINT supposedly returns us to the begining, >but the next READ gets EOD. > >Clearly - the POINT hasn't worked. > >And, as you might expect - this approach works just >great on z/OS. > >Does anyone know of any vagaries with the OS simulation >of NOTE/POINT? > >I did see that you can't code TYPE=REL (or TYPE=anything >for that matter.) But, I don't really care what the block >address is... just that it is the valid block address for the >beginning of the file. > >Thanks for any pointers! > > - Dave Rivers - I have successfully used POINT, READ, and CHECK Macros on CMS to read MVS datasets, but never had a need for NOTE. CMS OS simulation is at the MVS/XA level and IBM has no interest in upgrading anything on VM, (especially CMS), unless it benefits running Linux guests, which OS simulation does not. You cannot even get the latest so-called "Enterprise" versions of the program compilers, (like COBOL and PL/I), for VM/CMS. (Not sure exactly why, but my speculation is that the Enterprise versions would require CMS OS simulation to be updated.) I found a copy of the MVS/XA Data Administration Macro Instruction Reference on Bitsavers: http://bitsavers.org/pdf/ibm/370/MVS_XA/GC26-4141-2_MVS_EA_Data_Administration_Macro_Instruction_Reference_Jun87.pdf http://tinyurl.com/96gs5mr The first sentence under the NOTE Macro in the MVS/XA Reference contains this info: The NOTE macro instruction causes the system to return the position of the last block read from or written into a data set. All input and output operations using the same data control block must be tested for completion before the NOTE macro instruction is issued. So it sounds like the NOTE Macro will only work after a Read or a Write has been done to the dastaset, not after an OPEN Macro. -- Dale R. Smith ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
