SVECTOBS • RSCS-DEFIBED LOi STORAGE RSCS-defined low storage begins at hexadecimal .location 200 and is defined specifically
for the RSCS virtual aachine. It contains pointers to aodules that comprise the
supervisor, supervisor control queues, and queues of requests for supervisor services. 200 BEiPSll 204 208 SSAVE 20C 210 ACTIVE 214 !UIBMAP 218 !lIBSIZE 21C QUEUE 220 QUEUEBD 224 FREEQ
228 T1SKQ 22C MPXIOQ 230 SELIOQ 234 IOEXITQ 238 EXTQ 23C ALERTQ 2110 GIVEQ 244 QREQ Hexadecimal Field
I:isplacement Bame ------------ ORG 200 BEiPSi DS 208 SSlVE DS 210 lCTIVE DS DS 214 IUIBM1P DS 218 MIIBSIZE DS SVECTORS+X'200' D D'O' 2F 2F'0' X X'OO' AL3 lL3 (0) V (DMTMIPMS) F F'O' 248 DISP1IJCB 24C iAITRIQ 250 POSTREQ 254 IOREQ 258 TiSKREC 2SC M1IBREQ 2EO ASYBRE(; 264 lLERTBEQ 268 GIVBRlQ 26C TAKEREC 270 TVECTCBO 2711 TVECTCB1 278 TVECTCB2 27C TVECTCB3 280 TVECTCB4 284 TVECTCB5 288 TVECTCB6 28C TVECTCB7 Field Description, Contents, Meaning Leave rooa for machine extensions
Dispatched PSi for last dispatcher
General-purpose low storage save area
Identifier of currently active task
Address of task element for last dispatchee
Address of start of main storage allocation map Total nuater of pages in aain storage
, Section 3. RSCS rata Areas and Contrel Blocks 261

SVECTORS Eexadecimal Field
tisplacement Name
21C 220 224
228
22C 230 234
238
23C 240 244
248
24C 250 254
258
25C 260 264
268
26C 270 274
278
27C 280 284
288
28C QUEUE DS QUEUEND DS FREEQ DS TASKQ DS MPXIOQ DS SELIOQ DS IOEXITQ DS EXTQ DS ALERTQ DS GIVEQ DS QREQ DS DISPATCH DS WAITREQ DS POSTREQ DS IOREQ DS TASKREQ DS MAINREQ DS SYNREQ DS ALERTREQ DS GIVEREQ DS TAKEREQ DS TVECTORO DS TVECTORl DS TVECTOR2 DS TVECTOR3 DS TVECTOR4 DS TVECTOR5 DS TVECTOR6 DS TVECTOR7 DS v (SQUEUE) V (SQUEUEND) A (0) A (0) A (0) A (0) A (0) A (0) A (0) A (0) V (DMTQRQ) V (DMTDSP) V (DMTWAT) V (DMTPST) V (DMTIOMRQ) V (DMTASK) V (DMTSTO) V (DMTASY) A (DMTSIG) V (DMTGIV) V (DMTAKE)
A (0) A (0) A (0) A (0) A (0) A (0) A (0) A (0) TLINKS TROUTE TPORTS TTAGQ TCOM EQU TVECTORO EQU TVECTORl EQU TVECTOR2 EQU TVECTOR3 EQU TVECTOR4 Field Description, Contents, Address of start of sUFervisor queue
Address of end of last supervisor queue
element
Address of start of
Address of start of
Address of start of
Address of start of
Address of start of
element queue
free element queue task element queue
multiplexer I/O queue
selectcr I/O queue
asynchronous I/O request
Address of start of external request element
queue
Address of start of task asynchronous request
element queue
Address of start of GIVE request element
queue
Supervisor queue allocation request entry
address
Task dispatcher entry address Wait request entry address Post request entry address I/O request entry address
Task management request entry address Main allocation request entry address
Asynchronous interrupt request entry address
Task asynchronous signal request) A (ALERT) entry address
Task request GIVE request entry address
Task request TAKE request entry address
Task defined field
Task defined field
Task defined field
Task defined field
Task defined field
Task defined field
Task defined field
Task defined field
Link table address
Reserved for IBM use Svitchable port table address
Tag slot queue
Common routine chain
262 IBM VM/370 Data Areas and Control Block Logic