I recall such a TSO command from decades ago called simply "DSCB". I don't know its origin. Maybe it's on an old Share tape. However, this might need modernising for "recent" introduction of new DSCB types. Of course it probably would not supply a solution for VSAM data sets either.
Lennie -----Original Message----- From: IBM Mainframe Discussion List <[email protected]> On Behalf Of ITschak Mugzach Sent: 03 August 2024 09:25 To: [email protected] Subject: Re: How to "touch" mainframe files I am not in the brochure business for years, but I remember using ca disk utility to modify format-1 dscb . I was using it to change a file type from Sam to ps in order to delete the orphaned file. You can use it to alter other fields. May be there a free tool to do this. ITschak *| **Itschak Mugzach | Director | SecuriTeam Software **|** IronSphere Platform* *|* *Information Security Continuous Monitoring for Z/OS, zLinux and IBM I **| * *|* *Email**: [email protected] **|* *Mob**: +972 522 986404 **|* *Skype**: ItschakMugzach **|* *Web**: www.Securiteam.co.il **|* בתאריך שבת, 3 באוג׳ 2024 ב-6:42 מאת Thomas Berg < [email protected]>: > There is a lot of speculation in this thread. > Why not test the theories? > Both in z/OS (there were a JCL suggestion) and in unix/Linux. > > > Thomas Berg > > Den lör 3 aug. 2024 05:22Phil Smith III <[email protected]> skrev: > > > Well this is interesting, in that it sounds like I'm not the only > > one who's not 100% clear on what the rules are for "touch". Doc > > doesn't say much either (typical *ix doc). > > > > -----Original Message----- > > From: IBM Mainframe Discussion List <[email protected]> On > > Behalf Of Bernd Oppolzer > > Sent: Friday, August 2, 2024 6:31 PM > > To: [email protected] > > Subject: Re: How to "touch" mainframe files > > > > Phil asked: > > > > This makes me realize that I don't know what "touch" actually does. > > I mean, I know the effect, but what does it have to do to make that happen? > > > > IMO: > > > > The arcane Unix systems probably had only one timestamp per file, no > > difference for read/write, and files are simply chains of bytes, so > > I believe that what touch does is open the file for append, then > > append nothing and then close the file. > > This way the date (of last write) should be set to the current date > > (or timestamp). > > > > A simple open for read should IMO not change the date of a file. > > > > But that's some speculation on my part ... > > > > HTH, kind regards > > > > Bernd > > > > > > Am 02.08.2024 um 22:30 schrieb Phil Smith III: > > > Billy Ashton asked how to do the equivalent of a USS "touch" on a > > > z/OS > > data set. > > > > > > I'm wondering if there's something like the C "DD:ddname" filename > > specification hack that could be used. I know this would seem odd: > > run a batch job that uses BPXwhatever to run USS "touch", but if > > it's > possible...? > > > > > > This makes me realize that I don't know what "touch" actually > > > does. I > > mean, I know the effect, but what does it have to do to make that happen? > > If it's some filesystem function, a minimal C program might be able > > to > use > > the "DD:ddname" hack and that function. Googling suggests that it > > just opens the file and that that's sufficient to update it, but > > there has to > be > > more, since it can optionally update just the last access time, > > without updating the last changed time. > > > > > > In fact, the more I think about this, I now wonder what "last > > referenced" even means; I assume it's time of last access, not change? > > > > > > Billy wrote, in part: > > >> We don't want to do things like allocate, open, and print one > > >> record, as some of these files are huge (25-50GB). > > > Would you need to print a record to update "last referenced"? > > > Shouldn't > > reading a record suffice? Do you even need to do that? Why does the > > size > of > > the file matter here? > > > > > > I'm sure these are dumb questions but my in-depth filesystem > > > knowledge > > is for other OSes, so I'm just knowledgeable enough to be curious... > > > > > > ------------------------------------------------------------------ > > > ---- 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 > > > > -------------------------------------------------------------------- > > -- 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 > ---------------------------------------------------------------------- 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
