From:	CRDGW2::CRDGW2::MRGATE::"SMTP::CRVAX.SRI.COM::RELAY-INFO-VAX" 30-JUL-1990 21:21:21.89
To:	MRGATE::"ARISIA::EVERHART"
CC:	
Subj:	Re: Looking for Files-11 ODS2 volume documentation

Received:  by crdgw1.ge.com (5.57/GE 1.70)
	 id AA28482; Mon, 30 Jul 90 21:11:11 EDT
Received: From EQL.CALTECH.EDU by CRVAX.SRI.COM with TCP; Mon, 30 JUL 90 17:58:02 PDT
Date:     Mon, 30 Jul 90 17:55:04 PDT
From: rankin@EQL.Caltech.Edu (Pat Rankin)
Message-Id: <900730175406.3fc02a26@EQL.Caltech.Edu>
Subject:  Re: Looking for Files-11 ODS2 volume documentation
To: jim@umigw.miami.edu
Cc: info-vax@sri.com

> I am looking for a detailed explanation of Files-11 ODS2 volume structure
> including block layout on the disk, fields with different control blocks,
> etc.  RSX-11 had an Appendix that dealt with this for Files-11 ODS1 but I
> haven't seen anything similar for VMS.

     Appendix A of the Guide_to_VMS_Files_and_Devices [Gen.User 2A]
and Appendix B of Analyze/Disk_Structure_Utility [Sys.Man. 2] both
have short summaries.  Neither of these has the level of detail you're
looking for though.

     Some useful reference material--depending on your inclination and
abilities--is already available to you in SYS$LIBRARY:LIB.MLB.  Of
particular interest are
 $HM2DEF   Home block definitions for Files-11 Structure Level 2
 $FH2DEF   File header definitions for Files-11 Structure Level 2
 $FI2DEF   file identification portion of ods-2 header
 $FM2DEF   file allocation map portion of ods-2 header
 $FATDEF, $FCHDEF, $FJNDEF   attributes, characteristics, and journalling

		Pat Rankin, rankin@eql.caltech.edu