Aug. 1, 1979 ADTSECT ADTSECT describes the attributes of virtual disks (A-G, S, I, Z) accessed by a virtual
machine via theACCESS command. Space is allocated for the ADT when DMSNUC is assembled.
In the ADT, certain fields are defined for use by bothCMS and OS. For example, ADTHBcr
field at displacement 1C (hexadecimal) intoADTSECT is also defined as OSADTVTA for use
byOS simulation routines. ADTSECT is invoked by the ADT macro. 0 8 10 18 20 28 30 38 40 48 50 58 60 68
Hexadecimal Field
Displacement Name
ADTPTR
ADTFDA
ADTMFDAADTFSTC ADTCFST ADTNUM ADTLEFT
ADTCILADTMSK ADTPQM1
ADTPQM3ADTLFST ADTXNREC
ADTID A*1 A*2
ADTDTA
ADTMFDN
ADTHBCT
ADTCHBAADT1ST ADTUSED ADTLAST A*3 A*4 A*5 I A*6 ADTQQM ADTPQM2 ADTLHBA
ADTNACWADTRES ADTXAREC
Field Description, Contents, Meaning!2£ ]eag-gnl'y Disk§. Di§.t§. o ADTID DS CL6 Disk identifier (label)
6 ADTFLG3DS 1X A*1 Third flag byte Bit§. de!ined i!! !J21FLG,J ADTFUPD1 EQU X'80' First half of DMSAUD has been called
ADTFXCHNEQU X'40' Extra chain link(s) to be returned ADTFRWOS EQU X'20' Read/write OS or DOS disk ADTFSORT EQU X' 10' All FST hyperblocks and FST entries sorted ADTFORCE EQU X'08' CMS/DOS/OS disk forced to a read-only ADTFNOAB EQU X'04' For DMSAUD routine: Do not abend
if it is a disk error
7 ADTFTIPDS 1X A*2 Filetype flag byte
8 ADTPTRDS 1A Pointer to next ADT block in chain C ADTDTA DS 1A Device table address in NUCON 10 ADTFDA DS 1A File directory (PST AT) address
14 ADTNDS 1F Number of doublewords in master
file directory
18 ADTMFDADS 1A Master file directory address
1COSADTVTA DS OF VTOC address of OS pack
1C ADTHBCTDS 1F FST hyperblock count 140 IBM VM/370 Data Areas and Control Block Logic
machine via the
In the ADT, certain fields are defined for use by both
field at displacement 1C (hexadecimal) into
by
Hexadecimal Field
Displacement Name
ADTPTR
ADTFDA
ADTMFDA
ADTCIL
ADTPQM3
ADTID A*1 A*2
ADTDTA
ADTMFDN
ADTHBCT
ADTCHBA
ADTNACW
Field Description, Contents, Meaning
6 ADTFLG3
ADTFXCHN
if it is a disk error
7 ADTFTIP
8 ADTPTR
14 ADTN
file directory
18 ADTMFDA
1C
1C ADTHBCT