FICL FICL is a 2-byte table used in CMS/DOS to address system and programmer logical unit
blocks.
Byte 0 of FICL Foints to the first system class logical unit in the LUB table. This is always the first entry in the LUB table. The second byte points to the first programmer
class logical unit in the LUB table partition area.
The FICLPT field in the BGCOM blcck points to the FICL block.
o 1*1 I 1*2 Hexadecimal Field
Displacement Name o
1 SYSINDX DC PROGINDX DC J
AL 1 (0)
A11 (14)
Field Description, Contents, Meaning A*1 First BG system LUB index
A*2 Programmer LUBs index
Section 2. CMS tata Areas and Control Blocks 185

FRDSECT FRDSECT describes the fields used by to reference the four free chain element header blocks. FRDSECT is invoked by the macro The D!SFRT DSECT is pointed to ty a v-constant in and also by the lD!SFRT field in NUCCH. r 0 FREELN 8 10 FREELU 18 20 FREEHN
28 30 FREEHU 38 40 lFREET1B FRBELOW1 48 lC1LL 1*1 1*2 Hexadecimal Field
Displacement Hame Field Description, Conte_nts, Beaning o 10 20 30 lhe !.Qll.Q!!1!g FREELH DC FREELU DC FREEHN DC FREEHU DC Are the Four Free Chain Element Header -3F'0';IL1(FLiu+FLPA:iuciEY:HUCCODE,0) 3F'0',AL1(0,USERKEY,USERCOIE,O) 3F'0',AL1(FLNU.PLHC,NUCKEY,HUCCODE,O) 3F'O',AL1(FLHC,USERKEY,USERCODE,O) Blocks -Lov-storage nucleus
Low storage user chain
High storage nucleus
High storage user chain !.Q!l.Q!!1!g of .Q£ the
Four Free Chain Element Header Elocks pOliTEi--EQu---O------- ------Polnter to first free element NU! EQU 4 Number of elements in chain !AX EQU 8 !aximum size of an element FLAGSEQU 12 Flag byte FLCLH EQU FLCLB EQU FLHC EQU FLHU EQU FLPA EQU SKEY EQU in FLAGS --X'SO' X'qO' X'20' X'10' X'08' 13 in SKEY USERKEY EQU --x'io' NUCKEY EQU X'FO' Cleanup flag
Overlaid chain flag
High storage flag
Nucleus flag
Page availatle on chain Storage key for this chain User storage key
Nucleus storage key
186 IBM VM/370 Data Areas and Control Block Logic