12MKQCN, WAK£!!B!~ If NORET or DEFRET specified, build and stack CPEXBLOK to alert the
interruption handler and return via EIIT SVC otherwise go to
specified interruption handler. ~MKQCN!Q Entry via SVC to disconnect and logoff a virtual machine as a result of transmission line failures. Place the virtual machine in a wait
state, VMRSTAT=VMCFWAIT. DMKSCHDL --~lter virtual machine to unrunnable state. DMKFREE -~-storage for message for the system operator. DMKSCNRN, DMKSCNRD, DMKCVTBH, DMKSYSNM - FiII-in-message variables. -------- J2~KSCN.!!, DM~~~!RD, ~!!~~VTBH, Q!!~~!~NM Fill in message variables. Q~!.2£!!± Send the user disconnect message to the operator. 12!!!2CN, DS£~!R2 Build TRQBLOK, if needed, for 15 minute delay, schedule it, and exit
via SVC. !2!!!2£!, DS~!~Q~ After time elapse, TRQBLOK is unstacked and VMOSTAT is set to VMKILL for inevitable DMKUSOFF logoff operation. DMKDSPCH =~xit-to dispatcher.
3104/3105 INTERRUPTION HANDLER !2!!KRNH!£ Entry via DMKQCN or via CPEIBLOK for 3104/3105 resource
initialization. Locate the NICBLOK and check resource avaiability. 12~KR!]!, LI!!]~R! For resource unavailable, set RC=12 in CONTASK save area and return
task via DMKQCNET. DMKRNH, TAGTA~! For resource available, set CONTASK values per input and output task requirements. 12!!KR!]!, TA~!£;!2 Move CONTASK from RDEVBLOK chain to NICBLOK chain. DMKRNH, RNSTART ---on-3104/3705 available condition, search NICLIST and build an IOBLCK if required. DMKRNHIC, RNEXLST ---search the-NICBLOKs for CONTASKs to be sent to 3104/3105, build and
chain for output. 1211KRN]!, RN£J!!!! Perform necessary function for each resource. 12~KIOS~ Start output I/O operations. 121!KRNJ!, !U!l£J!!l Return via R1. 12~KR~J!!!~ Entry via SVC to schedule resource control tasks. 12MKRNH, RNH!12!! Build control CONTASK and enqueue it for execution. 12!!!R!!J!, ~!!CP!! For NORET specified, build and stack a CPEIBLOK to perfor. SVC exit. 12MKR!1!, RNDE!l! Attempt to start output via GOTO DMKRNHIC. 12~K RI.!!, !n!l12l~£ Entry for 3104/3105 recovery. CP Method of Operation and Prograa Organization 1-199

DMKNLDR -~oad the 3104/3105, if it was not previously loaded. DMKF!l! Get storage to build CKPBLOK (telecommunications control block), if
necessary. ~MKRNH, RNS~lX~ Record active line and enabled terminal flag bits. ~MK~!l!! Clear CONTASK chains. ~!!!2~!!Q Force disconnect to all active users. DMKNLEMP ---nU8P-the 3104/3705.
DMKNLDR ---aeload the named program. ~~KR!!!!~ On "IPL complete" signal, reenable resources.
DMKFRET ---aelease the CPEXBLOK. ~11!12~~£!! Exit to dispatcher. Q1!KRNl!!!! Entry via IOBLOK to perform input and output interruption processing. DMKRNK, RNIOERR ----For input-process failure. Analyze the failure and if related to the
3104/3705 and not to a particular resource, either retry or dump and
reload. ~MKRN1!, RE!~!H!f Interpret response codes for each BTU received and schedule necessary
control operations. DMKR!1!, CMP!~!~ Generate response to a read error. ~!!KRNH, CMP!!!lI~ Generate response to a write error. DMKRNJJ, CMP~Q!! Generate response to a contact task error. ~!1KR!.!!, CO!1~!~£ Generate response to a disconnect task error. ~MKRNH, CO!1~!X!! Generate response to a control task error. ~l1KRNH, UN~Q!!!! Generate response to a unsolicited read. ~~!.Q£!!l!! Return completed CONT1SKs. ~!1KR!], RN~X!!!! Attempt to restart the 3104/3705. DMKDSPCH --~xit-to the dispatcher. DMKRNHIN ---Entry via IOBLOK to perform input and output interruption processing. DMKRNH, SCHREAD ---on-output~--exa.ine interrupt status per IOBLOK values and if ATTN, build and start a read CCW sequence. ~~KR!], !!lQ~!!£ If unit check and fatal, du.p and reload the 3704/3705. ~~!.B!!], RNQ1!~!J2 If pending ATTN cleared via 510 - ~~KIQ~2!! Reschedule write operations. ~1!KR!!!, RN~!!Q!R!! If unit exception, set RDEVSLOW and reschedule rejected CONT1SKs. R~!2£!~! Return only CONTASKs without CONRESP or CONSPLT set. Retain others
until final response is received.
1-200 IBM VM/370 System Logic and Problem Deteraination--Voluae 1