Hello Listers, I have a question about how additional extents for a dataset are chained together for files on EAV volumes.
If I understand correctly: - The format 8 record has slots to keep track of the first 3 extents of a dataset (DS1EXT1/DS1EXT2/DS2EXT3). - If there are more than 3 extents, the DS1PTRDS will point to a format 9 record - The format 9 record contains pointers in the DS9F3 area to point to up to 10 format 3 records - Each format 3 record can point to up to 10 extents - The DS9PTRDS description contains the text: "FORWARD CHAIN POINTER (CCHHR) TO THE NEXT FORMAT 9 DSCB -> OR TO THE FIRST FORMAT 3 DSCB IF DATA SET HAS MORE THAN 3 EXTENTS. OTHERWISE ZERO." There wouldn't be a format 9 record if there weren't more than 3 extents. So I think the comment on the DS9PTRDS field is confusing. It seems there are 2 ways extents could be chained via the DSxPTRDS fields: DS9PTRDS -> the next FMT 9 record, whose DS9PTRDS -> another FMT 9 record, or DS9PTRDS -> the next FMT 3 record, whose DS3PTRDS -> another FMT 3 record My question is: If there are more than 13 extents, will the DS9PTRDS always point to another format 9 record? Or are there circumstances when it will point to a format 3 record? Or, maybe restated: What will the DS3PTRDS field contain when the format 3 record has been pointed to by a format 9 record, when there is another format 3 record? The graphics in https://www.ibm.com/docs/en/zos/2.5.0?topic=components-data-set-control-block-dscb-types show DS3PTRDS->another format 3 for non-EAV records, but they don't show multiple format 9 records. Thanks for your help! Wendell ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
