ADTSECT
Hexadecimal Field
Displacement Name Field Description, Contents, eeaning 6C ADTIAREC DS 1F Address of tlock of extra chain link records
ADTLBM
ADTLDM EQU EQU ADT2ND-ADTSECT Length of minimum ADT block (in bytes)
ADTLBM/8 Length of minimum ADT blcck in dcublevords
ADTLB
ADTLD EQU EQU *-ADTSECT
(ADTLB+7)/8 Q!her Parameters
ADTRL ---EQU---aoo ADTMIBML EQU 10 Length of full ADT block (in bytes)
Length of full ADT block in dcublevords
Lcgieal reccrd length Maximum bit map length (number ef records)
for 3330 Table DTAD EQU --0-- Device number
DTADT EQU 3 Device type byte
DTAS EQU 4 5ymbelic device name 142 IBM VMj370 Data Areas and Central Block Logic

AFTSECT AFTSECT is used te describe a file currently open for a read or write. The AFT is created
when a file is opened. Space fer up to five AFTs is availatle in tMSNUC; any others must
reside in free storage. AFTSECT is invoked via the AFT macro.
Hexadecimal
o
8 10 60 68 70 78 80 88 90 98 AO Displacement
------------ 0 0 A4 A8 14C 150 1F4
1F8
29C 2AO 344 348 0 2 4 8
A
C 10 r--------------------------------------------------------,
AFTCLD AFTCLN AFTCLA
AFTDBD AFTDBN AFTDBA
AFTCLB
A*1 AFTPFST AFTIN AFTID
AFTFCLA AF'I'FCLX AFTCLDX A*2 1/////1 AFTOCLDX 1///////////////////////////
AFTD
AFTM AFTIC
AFTIL
AFTADT
Field
Name Xile AFT START DS OD DC 41F'0' DC A (*+4)
DC 41F'0' DC A (*+4)
DC 41F'0' DC A (*.4) DC 41F'0' DC A (*+4)
DC 41F'0' DC A (0) DC 2F'0' AFTCLD DS H
AFTCLN DS H
AFTCLA DS F
AFTDBD DS H
AFTDBN DS H
AFT DBA DS F
AFTCLB DS XL80 AFTN
AFTT AFTiP AFTRP
AFTFCL A*3 A*4 AFTtEC AFTYR AFTPTR
Field Description, Contents, First AFT l:lock Second AFT l:lock Third AFT block
Fourth AFT tlock
Fifth AFT block
Address of next AFT tlock (in free storage)
Reserved for IBM use Disk address of current chain link Numter of current chain link
Address of chain link buffer
Disk address of current data block
Number of current data block
Address of current data tlcck Chain link tuffer frcm first chain link Section 2. Data Areas and Contrel Blocks 143