The VTOC itself does not have a data set name, as it is not a data set that can be allocated through programmatical use of DADSM or via JCL. IMASPZAP allows you to specify FORMAT4.DSCB as the (pseudo) data set name of a VTOC on a //SYSLIB DD statement so that you can display or even alter data within the VTOC using IMASPZAP, but that is unique to IMASPZAP. Other clever software has been known to put 44 consecutive bytes of X'04' in a field where normally a (real) data set name would go, such as within a JFCB or CAMLST, and then use a system service like OBTAIN or even OPEN to access the VTOC as if it were a (real) data set. A VTOC can, of course, be conceptually considered just another sequential data set from a certain point of view. You can OPEN it and then use QSAM, BSAM, or EXCP to read sequentially through it or follow chains of DSCBs within it (assuming you can get past the security controls that may or may not be in force for your LPAR).
Theoretically, you can have a data set name with anything in it, but certain names may cause confusion, such as FORMAT4.DSCB, which is why I mentioned this one. Some others that come to mind are SYSCTLG, SYS1.SYSJOBQE, and PASSWORD. These had very specific meanings and did refer to real data sets long, long ago and in a galaxy far, far away. Bill Fairchild Franklin, TN ----- Original Message ----- From: "Paul Gilmartin" <[email protected]> To: [email protected] Sent: Wednesday, September 25, 2013 10:33:19 AM Subject: Re: DSNAME Syntax On Tue, 24 Sep 2013 22:43:27 +0000, DASDBILL2 wrote: >FORMAT4.DSCB could cause some confusion if not used solely with IMASPZAP. > So I infer that a DSNAME beginning with a period has some special significance when in a format-4 DSCB. Hmmm. I'm pretty naive at this. Looking in: Title: z/OS V1R13.0 DFSMSdfp Advanced Services Document Number: SC26-7400-14 1.1.1.5 Format-4 DSCB The only hint of something that might be a DSNAME is: Exception: The format-4 DSCB has a 44-byte key of X'04' bytes not shown in Table 4. But I understand that's the DSNAME of the VTOC itself, and would be unaffected by a stored data set whose name begins with '.'. What am I missing? >----- Original Message ----- >From: "Paul Gilmartin" >Sent: Tuesday, September 24, 2013 5:04:38 PM > >>At 07:46 -0400 on 09/24/2013, John Gilmore wrote about Re: DSNAME Syntax: >> >>>The 'period' problem is an old one. It has a syntactic function in >>>DSN[AME]= values, and it is out of place as the first character in a >>>standard one. >> >Ah, but I had asked about quote-framed DSNAMEs, where apparently >the standard rules are largely suspended. I can use lower case, >embedded blanks, long qualifiers, but not an initial period. Does this >reflect the DOS conventions? > >Are there data set names not beginning with a period that likewise >are rejected by JCL when quote-framed? (Well, I found one, not very >surprisingly: a data set name of all blanks causes allocation of a >temporary data set instead. Still others?) Thanks, gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
