From: hoffman@xdelta.zko.dec.nospam Sent: Tuesday, June 06, 2000 9:26 AM To: Info-VAX@Mvb.Saic.Com Subject: Re: How to get all Global Section Names? In article <393C1BDF.5B80678@wcom.com>, Arasu Ramalingam writes: :I am working on a problem which requires me to get a list of all (Group) :Global Sections existing in a OpenVMS AXP system and monitor them :periodically. I could get a listing through System Dump Analyzer using :SHOW GSD/GROUP at DCL level, and read that listing file through spawing :a subprocess. Instead of doing this in a round about way, is there a :better method or system service/utility to get the Global Section names? :I will appreciate any help. Short answer: there is no supported interface for this. Long answer: you need to traverse the GSD data structures in kernel mode to do this. This isn't particularly difficult, but it does require the application be linked against the OpenVMS Alpha base image. (Which means that the application is version-dependent, and can require source rebuilds or redesigns if/when/should kernel data structures change.) And it also means that if you should make a boo-boo, said boo-boo can trigger an OpenVMS system crash or a kernel-mode data corruption. If you are familiar with SDA, then the group global section listheads are EXE$GL_GSDGRPFL/...GRPBL and EXE$GL_GSDDELFL/...BL (the latter is the delete-pending list) will be of interest. You can use SDA to walk these structures, and get an idea of what these look like. On OpenVMS Galaxy, EXE$GL_GLXGRPFL/...BL will be of interest. Replace GRP in the symbols with SYS for the system global sections. If you should want to walk the chain, acquire the EXE$GL_GSDMTX mutex for read. Most of this stuff is covered in some detail in the Internals and Data Structures Manuals -- though the OpenVMS Galaxy shared memory is not, it works similarly to the other section management stuff. The supported interfaces for acquiring this information are SDA and INSTALL LIST/GLOBAL, though parsing the output of these commands is NOT supported. Ask The Wizard answer: There was to be an answer appearing via the Ask The Wizard mechanism, but I'll ask that the discussion over there be nuked. (Per the Ask The Wizard rules, please do not cross-post questions between the Ask The Wizard area and the newsgroups. Yes, cross-postings are noticed. No, they do not encourage faster answers -- if you need a an answer or if you need a faster answer than the week-or-two turnaround in the Wizard area, I would encourage direct contact with the Compaq customer support center. Thanks!) --------------------------- pure personal opinion --------------------------- Hoff (Stephen) Hoffman OpenVMS Engineering hoffman#xdelta.zko.dec.com