If there was a previous buffer page list, free it. Save the start of
the user directory pointer in DMKSYSUD, and return to caller with a cc=O in the VMPSi. SAVE THE 3704/3705 CONTROL PROGRAM IMAGE PROCESS Entry from DMKHVC and DIAGNOSE code 50. Per the system VMBLOK, locate the DftKRNTBL. The CCPARM virtual address is contained in R1 of
the DIAGNOSE instruction. Match via search CCPARM; CCPNAME with DMKRNTBL entries. Verify DASD space requirements for 3704/3705 control program and
resource data. The volume required to save (NCPVOL) as indicated in
the NCPTBL entry must be available and mounted on the system, on a CP owned and supported paging device. Save resource data on the NCPVOL device. CCPARM supplies the starting
address and size parameters for this write operation. 12!1KS!!£, SVN£fl!! Save 3704/3705 control program image on NCPVOL device. CCPARM also
provides the parameters for this similar operation. Store cc=O on no errors and return to caller. SPOOL PILE CHECKPOINT AND RECOVERY Entry from CP initializer, DMKCPI to initialize the checkpoint
cylinders. Per DMKSYSCH, get a virtual page for the checkpoint
cylinder and set up the device code in the system residence device.
In addition, set up local data areas such as pages per cylinder and
checkpoint cylinders. Loop through each SPBLOK in the system and checkpoint it in a slot on
the checkpoint cylinder. Then loop through each remaining slot and
mark it empty. Place the map delimiter of the last non-empty slot in the aap. DMKPTRUL -- Unlock the map page. Return to caller. DMKCKSPL from any routine that adds, deletes, changes, the status of
closed spool files. Lock the routine, or wait until it becomes
unlocked. Bring the aap page into storage and set up the device code
of the system residence volume.
1-224 IBM VM/370 System Logic and Problem Determination--Voluae 1

DMKCKS, If the change is applicable to a SHQBLOK (hold queue block), make appropriate change on the checkpoint cylinder. DMKCKS, CKSPL1 the-change is applicable to a SFBLOK, either add, change, or
delete it on the checkpoint cylinder. DMKCKS, CKSPL5 -- If-the--change affects START or DRAIN command
cylinder.
a spooling device RDEVBLOK (for example, a
issued), mark the change on the checkpoint DMKCKS, CKSEIIT ---unIock:the-routine. Unlock the page map and exit to caller. DMKCKSWM via DMKCPI during VM/370 reinitialization process whenever the
records for closed spool data need to be reconstructed. Get a virtual
page for the map of the checkpoint cylinder and set up the device
code of the system residence volume. In addition, set up local data
areas. For slots having real device entries, set or reset the RDEVDISA and RDEVDRAN and move in the check pointed device classes into RVDEVCLAS. 12MKCKS, For slots containing spool hold queue block, chain this to the SHQ chain. CK S !!1J Get storage for SFBLOK space and set flags depending upon its last
checkpoint activity. DMKCKS, CKSWM4 If the fIle SFBLOK was active, chain it to the appropriate printer,
reader, or punch chain. J2!1KCKS, CKS!M5 Allocate the DASD buffers of the spool file by reading each buffer to
determine the next one and then allocate this DMKCKS, ror the dump spool file, the buffers are allocated sequentially from
the beginning to the end. DMKCKS, CKSWM9 ---Set up the-map delimiter for the end of non-empty slot; then set up a
new spool file identity (spoolid) higher than existing numbers.
Return to DMKWRM. INTER-VIRTUAL MACHINE COMMUNICATION DMKVMCFC from DMKHVC and the DIAGNOSE instruction code X'68'. Builds a YMCBLOK and initializes it with data from the user's parameter list, VMCPARM. The virtual address of VMCPARM is contained in bits 8-11
(rx) of the DIAGNOSE instruction. DMKVMC, Branch table to pass control to the appropriate subroutine based on
the subfunction code in VMCPARM. CP Method of Operation and program Organization 1-225