GIVE/TAKE §lVE The format of a GIVE Request Table is: I 0 Synch Lock I , 4 Task name or A(GIVE Element) I I 8 A (GIVE Request Buffer) I I C A (GIVE Response Buffer) I .J When a task requests the services of another task via a GIVE request, the second field of
the table above contains the task name of the task to which the task is to be sent. When DMTGIV builds a GIVE element for the request, it overlays this task name with the address of the GIVE element.
The task Ferfor.ing the requested service builds a table called the TAKE request
table, which corresponds to the GIVE request table. GIVEE defines symbolic addresses for items used in processing a GIVE request. GIVEQ in SVECTORS points to the queue of GIVE elements used in task-to-task cOiimunicaticns. The GIVEADDR field of this DSECT is the address of a GIVE request table, which, in
turn, contains addresses of buffers for elements describing requests and resFonses to
requests. These tables are described below; the elements that fill the buffers are
described in "AFpendix C: RSCS Request Elements." 0 4
8
C
Hexadecimal Displacellent ------------ 0 4
8
C E F I , I GIVENEXT I I I I GIVEADDR I I I I GIVENAME I I I I/////////GIVESPAR/////////I GIVENID GIVERID I Field Name GIVENEXT DS 1F GIVEADDR DS 1F GIVENAME DS CL4 GIVESPAR DS AL2 GIVENID DS 1X GIVERID DS 1X Field Description, Contents, Meaning
Address of next GIVE element
Address of GIVE request table in sending task's storage
Task name of receiving task
Reserved for IBM use
1-byte identification of receiving task after
the TAKE request has been processed
1-byte identification of sending task Section 3. RSCS rata Areas and Contrcl Blocks 253

IOE IOE defines symbolic addresses of elements and other information associated with an I/O operation requested by a task. MPIIOQ and SELIOQ in SVECTORS point to queues of I/C elements for the multiplexer and
selector channels, respectively.
The IOTABLEA field points to the address of an I/O table defined by IeTAELE, which is
described in this secticn.
o 4 8 IOSTAT C lOADDR Hexadecimal Field
Displacement Name ------------ 0 IONEIT DS 1F 4 IOSOBQ DS 1F
8 IOSTIT EQU *
Bits defined in IOSTAT SENSING---EQO-X'80'--- CHANDONE EQU X'40' 8 IOTABLEA DS 1F
C IOADDR DS AL2
E IOSBCHAN DS 1X F IOID DS 1X lONEIT IOSUBQ IOTAELEA IOSECHAN IOID Field Description, Contents, Meaning
Address of next active I/O element
Address of first inactive I/e element for a
given subchannel for current IIC operation
(first tyte of IOTABLEA)
Flag set to 1 while automatic sense is
active
Flag set to 1 when subchannel terminates
Address of I/O request table in task storage
Address (cuu) of the device requesting
current I/O operation
Subchannel address; 1-byte; assigned by MSUP ID of task associated with this I/O cperation
is 1-byte and assigned by MSOP 254 IBM VM/370 Data Areas and Control Block Logic