IPL.HELPCMD2.D1

Usage Notes
1.  IPL simulates the LOAD button and the device address switches on
    the real computer console. The specified virtual address is
    accessed and the required input/output operations are performed to
    retrieve the IPL data.
2.  Optionallv, the IPL procedure can be stopped just before loading
    the virtual PSW except when initial program loading a named system.
    Also, parameters can be passed to the virtual machine's general
    registers.  When the simulated load function is complete, CP
    initiates execution of the virtual machine by loading the 1PL PSi
    which was stored during the simulation process.
3.  Care must be used when passing parameters to a named system
    (systemname).  Named systems expect certain registers to be
    initialized when they are given control. Indiscriminate use of the
    PARM operand could overlay a previously initialized register
    causing unpredictable results.
4.  The IPL simulator program occupies one page (4096 bytes) of storage
    in your virtual machine.  Therefore, if the system being loaded
    utilizes data remaining in storage by the previous system, care
    should be taken as to where that data is located.  The starting
    address of the overlaid virtual storage is:
      Virtual Storage Size       Location of IPL Simulator Page
        256K and above           = 20,000
 
        Less than 256K           = 1/2 the storage size
 
        For example:
          storage size=200K then the IPL Simulator is loaded at 100K.
5.  Any logical lines following the 1PL command are ignored since the
    execution of the IPL command transfers control from the CP
    environment to the virtual machine environment.
 
6.  Some CMS routines and programs are stored on disks and loaded into
    storage as needed.  Since this storage area is not contiguous with
    your virtual storage, the saved segments that are loaded in this
    area are called discontiguous segments (DCSS). However, the only
    discontiquous saved seqment.  The user can indicate an alternate
    segment to be loaded bV issuinq an IPL command with this format:
 
        IPL [CUU | systemname ] PARM SEG=segmentname
 
where:
SEG=segmentname
        indicates the name of the saved segment to be loaded whenever
        the CMS Editor, EXEC processor, or as simulation routines are
        needed.  Eiqht characters must be entered for segmentname;
        either assiqn an 8-character segment name when you code the
        NAMESYS macro for your installation, or be sure that the
        operator enters trailing blanks if segment name is less than
        eight characters long.
        The CMS batch facility loads whatever segment is specified
        on the first IPL command issued for the batch virtual machine.
        Thus, if the first 1PL command for a CKS batch facility
        machine is:
 
        IPL CMS PARM SEG=CMSSEG02
 
        all subsequent IPL commands issued by the CMS batch facility
        specify the same segment name (CMSSEG02).
7.  The BATCH option in the PARM operand indicates that the CMS initial
    proqram load is beinq performed in a batch instead of an interactive
    virtual machine.  This option causes the :KS nucleus to issue the
    CMSBATCH command to load the batch processor.  Specifying
    the BATCH option eliminates the need for operator intervention
    between jobs.  Consult VM/370 CMS Command and Macro Reference for
    information on the CMSBATCH facility.
8.  CMS users can use the PARM operand to pass the AUTO:R (automatic
    carriage return) option to the CMS initialization routine.  AUTOCR
    simulates the pressing of the ENTER key as input to the virtual machine.
    This results in automatic execution of the user's PROFILE EXEC, if it
    exists on virtual minidisk 191.
 
    Note: For a disconnected CMS service virtual machine, this mechanism
    can prove to be very useful.  The name of a CMS restart routine may
    be specified in the CMS nucleus. In the event of an ABEND, the specified
    restart routine receives control instead of the service virtual machine
    entering a disabled wait state. If this routine issues an 1PL CMS PARM
    AUTOCR command, the PROFILE EXEC executes initial setup procedures that
    allow the service virtual machine to reestablish itself.