FVSECT Hexadecimal Field
Displacement Name lA4 lA6 lA7 lA8 lA9 lAA lAB lAC lBO lB4 lB8 lBC SIGNAL DC UFDBUSY DC !!i!§ WRBIT EQU UPBIT EQU FNBIT EQU ERBIT EQU DIOBIT EQU KXFLAG DC !!i!§ KXWANT EQU KXWSVC EQU DC FLGSAVE DC FVS:FLAG DC ERSFLAG DC PVSERASO DC FVSERASl DC FVSERAS2 DC
READCNT DC
DC H'O' X'OO' in UFDBUSY --X'80'--- X'40' X'20' X'10' X'08' X'OO' in KIP LAG --X'80'-- X'Ol' X'OO' X'OO' X'OO' X'OO' F'O' P'O' P'O' P'O' P'O' Table lCO lCO lC8 lDO lD4 lD6 lD8 lDA lDC lDE lDF lEO lE4 lE6 lE8 lEC STATEFST FVSFSTN FVSFSTT FVSFSTDT FVSFSTWP FVSFSTRP FVSFSTM FVSFSTIC FVSFSTCL FVSFSTFV FVSFSTFB FVSFSTIL FVSFSTDB FVSFSTYR FVSFSTAD STATERO FVSFSTAC STATER 1
DS ---aD DC D'O' DC D'O' DC 2H'0' DC H'O' DC H'O' DC H'O' DC H'O' DC H'O' DC C' , DC X'OO' DC F'O' DC H'O' DC 2C' , DC A (0) EQU FVSFSTAD DC A (0) EQU FVSFSTAC Field Description, Contents, SIGNAL = Scratch halfword used by READMFD
or ERASE
= COCO, X'FFFP', X'llFE', or X'PFPD' 00, Fl, FE, or FD A*3 Nonzero means UFD is being updated
A*4
A*5
A*6 £2.£1 A*8
A*9 WREUF UPDISK - READMlD PINIS ERASE - ALTER -READFST RDTK/WRTK DMSAEN (atend recovery routine) tMSI1S (SVC handling routine) HX flags HX wanted as soon as possible
Hold HX until any SVC activity
Reserved for IBM use Par scratch use (for example, by Par general use (as needed) (QI Plag for use by ERASE or RENAME RO to/from FSTLKW (for ERASE) RELUPD) Rl to ACTLKP or PSTLKW (for ERASE)
Address of free storage used by ERASE
Current read count (DMSBRD) Reserved for IBM use
from S'IATE -Pull-PST-of file (STATE) Pilename Piletype Date/time last written Write pointer Cite. ID)
Read pointer (item ID)
File.ode
Numher of items in file tisk address (first chain link)
Fixed (F)/variable(V) indicator
Flag byte Length of largest item in file
Number of data tlocks Year last written
A(active disk table for this file)
A(real PST entry for this file)
194 IBM VM/370 Data Areas and Control Block Logic

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