12MKRNH, !!NST!R! Attempt to restart the 3704/3705. DMKDSPCH dispatcher.
HANDLING REMOTE 3270 WITH BINARY SYNCHRONOUS LINES DMKRGBEN when the NETWORK ENABLEjDISIBLE command is issued. Get storage for the necessary CONTISK. IOBLOK. and if applicable, BSCBLOK. DMKRGB, LINESUP ---Set up-required CCWs and control data in the COBTASK for tasks.
These tasks include: enabling the binary synchronous line, enabling a
device, LOGO messages, screen formatting, and disable line or device
(logoff) • DMKFREE -- For-logon function build logon V!BLOK. 12 MK IOS.2!! Start line I/O or device I/O, for not busy condition.
DMKRGB, RGFTASK ----For busy-condition, build CPEXBLOK and exit to caller. 12 MK RGB1£ Entry from DMKDSP. On a not available line condition, exit to
dispatch. For available line, process the associated CONTASKs by
queueing the related resource from the NICBLOK. RGS!!R% Process .QMKIOS2!! n,...TT SID on a no CONTASK queued condition. Process selection SIO on available resources and not in control aode
per NICBLOK conditions and the CONTASK CONSTAT field. DMKDSPCH - Exit-to dispatcherQ DMKRGAIN from D!KIOS, examine line interruption condition. Discard any
of the following and go to the dispatcher: nonbinary synchronous
line, copied IOBLOK, unsolicited interruption, bisync line flagged
not- in-use, nonter.inal class device.
DMKRGA, FATALER ---Por 10 B FATAL condition or any nonzero condition code, free all
related CONTASK, IOBLOK, IOERBLOK, and BSCBLOK. Log off all affected users on that line • .QMKMSW!! Send message to the system operator. CP Method of Operation and Program Organization 1-201

Exit to dispatcher. DMKRGAIN or terminal response did not fall in the previous category,
process via TP code branch. The code in the fifth byte of the ending CCli or IOBCSll-8. TP Code TPOO-- TP01 TP02 TP03 TP04 TP05 TP06 TP07 TP08 TP09 TP10 TP11 DMKDSPCH Function Error-Handling cew
Enable/disable function Write EOT (sequence prior to polling and addressing) Write polling or addressing characters
Handle station's status and sense aessage
Read response to addressing Write response to text NO-OP following POLL command Unit exception condition (timeout)
All reset commands
Read/write text
Read response to text the dispatcher. DKKBSCER ---Entry via DKKIOS and SVC 8 to process errors related to the binary
synchronous line unit check and channel error conditions. On first
error pass, move the IOERBLOK pointer from the IOBLOK to the RDEVBLOK, reset retry and fatal flags, set the ERP flag and call DMKFREE. DftKFREE storage for a work area for retry CCWs. On a not first error condition, test for unrecoverable error
condition. Unrecoverable errors include:
program check, protection check, chaining check, equipment check,
interface control check and channel control checks. If one of these,
notify the system operator. Reset flags, initiate error recording
and Free IOERBLOK. Go back to scheduler. DKKRGA TP code, sense data CSW residual count and retry count to
determine retry or IOBFATAL flag setting. 1-202 IBft VM/370 System Logic and Problem Determination--Volume 1