IBADECE
IHADECB, which is invoked via the CMSCB macro, is the simulated data event control blcck
used for CMS processing of OS macros and OS access methods. The ICEECBPT field in
FCBSECT points to IBADECB.
Hexadecimal
o
8 10 18
Displacement
------------ 0 4
6
8
C 10 14
18
DECSDECB
DECDCBAD
DECIOBPT
DECRECPT
Field Name DECSDECB DS F DECTYPE DS H in DECTYPE DECBRD BQU --X'80'--- DECBWR EQU X'20' DECLNGTB DS B
DECDCBAD DS A
DECAREA DS A
DECIOBPT DS A DECKYADR DS A
DECRECPT DS A DDNAM EQU FCBDSTYP BLK EQU X'10' BS EQU X'20' DA EQU X'20' FXD EQU X'80' IS EQU X'80' LOC EQU X'08' MOV EQU X'10' PS EQU X'40' PO EQU X'02' PREVIOUS EQU X'80' QS EQU X'40' UND EQU X'CO' VAR EQU X'40' DEC'IYPE DECLNGTB
DECAREA DECKYADR Field Description, Contents, Meaning Event control block
Type of I/O request
Read SF Write SF Length of key and data V(data control tlock) V(key and data, buffer) V (IOE) V (key) V(block reference fieldj
Filetype = data set name
RECFM=blocked records !UCRF=BSAM DSORG=direct access
RECFM=fixed-length records
DSORG=indexed sequential
MACRF=locate mode !UCRF=move mode
DSORG=physical sequential
DSORG=partitioned organization OFLGS=previous I/O operaticn MACRF=QSAM RECFM=undefined format records
RECFM=variatle-length records
Section 2. CMS rata Areas and Control Blocks 195

IOSECT IOSECT describes the fields used by DftSITI for save registers, I/O cld PSi, and other
data when handling I/O interrupts. IOSECT is pointed to by the AIOSECT field in NUCON. o lOS AVE 40 IONTABL AUSRITBL 48 AUSRILS7 50 OLDEST 60 NEXTO 70 IOPSi 78 IOCSi 80 HOLD VSTRANGE 1///1////////// 88 //////////////////////////////1/////////1///1//////////1 , Hexadeci.al Pield Displace.ent Na.e Pield Description, Contents, !eaning o
40
44
48
4C
50
60
70
78
80
84
86
88 IOSIVE DS IONTIBL DC AUSRITBL DC AUSRILST OLDEST NEXTO IOPSi IOCSi HOLD VSTRANGE DC
DC DS DS DS DS DC
DC
DC
DC 16P P'O' A (0) P'28' A (0) 4P 4P 2P 2P P'O' H'O'
1H' O· 2P'0' Register save area
Size of user interrupt table in doublewords
Address of user interrupt table
Length of each entry
Address of last entry in table Oldest I/O old PSi and CSi Next oldest I/O old PSi and CSi Newest I/O old PSi Newest CSli Holds entry pointer for device Unknown device address saved here
Reserved for IB! use
Reserved for IB! use
196 IBM VM/370 Data Areas and Control Block Logic