The blocksize does not have any effect until the data set is opened. The current value (perhaps specified in the JCL) will be stored in the DSCB as part of allocation but it can be overridden in the DCB or the open exit.
JCL allocation occurs before your program executes. Therefore, it uses the block length value in the SPACE parameter rather than the blocksize value (which is not yet final). After the B37, the data set should be available for review. Look at the DSCB and see what really is going on (block size, lrecl, recfm, extents, etc). -----Original Message----- From: Charles Mills [mailto:[EMAIL PROTECTED] Sent: Friday, June 16, 2006 1:42 PM To: [email protected] Subject: Re: Track capacity? A follow-up question if I may. I am trying to figure out the meaning of the sentence (in JCL Reference, under SPACE=(blklgth ...) "The value specified for block size uses block length in this computation, with the exception of the value zero." I can't quite assign a meaning to that sentence. If ... - the JCL specifies SPACE=(605,(4640,580)) (with no AVGREC) - the (output) DCB is defaulted to BLKSIZE=0 and the open exit does not set BLKSIZE - the dataset is new - SMS is active on the system (but I don't think this dataset is SMS-managed) .. is there any reasonable circumstance under which MVS will NOT allocate roughly 104 tracks primary? Is the zero BLKSIZE fouling me up somehow? FWIW, the evidence is that it is running out of space after about 600 121-byte records, which SHOULD be being blocked x 26 to 3146 (but other possible errors might be resulting in unblocked records - as I said in another post, I'm working on a bug here under circumstances which limit the amount of information I have to go on). Thanks everyone for your patience. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Charles Mills Sent: Friday, June 16, 2006 10:13 AM To: [email protected] Subject: Track capacity? Where can I find 3390 track capacity tables or formulas? I haven't done this in so long I think the last time I did this it was for a 2314. Specifically, I am trying to figure out: - If the DD statement says SPACE=(605,(4640,580)) how many tracks will have been allocated (primary and each secondary)? ---------------------------------------------------------------------- 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 ---------------------------------------------------------------------- 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
