System initialization is simplified if:
1. All V8/310 resident volumes (specified in the SYSOWN list for
paging and spooling) are mounted and ready at IPL time. If volumes
specified in SYSOWN are not mounted when yeu IPL V8/370, they are
not available to You must mount and attach them later if you
need them by using the ATTACH command.
2. Volumes containing user minidisks (such as the eMS system residence volume) are mounted and ready at IPL time. However, volumes not required for startup can be attached to the system after the V8/370 program is up and operational. Once loaded, CP reads the volume identity labels of all available DASD devices, and calculates the real machine's storage size. If the configurat;on differs from that specified during system generation (SYSOWN volumes not mounted or storage size net equal to SYSCOR), a
message is printed at the system console and operation continues. If a
real machine has aore storage than what was specified on SYSCOR, it is
not used. For example: if a real machine's storage size is 1 megabyte and SYSCOR is set to 512K, 512K is used. If less storage is actually
available in the real machine than the specified SYSCOR value, the
lesser figure is used.
If the SYSCOR macro had specified AP=YES and the attached processor
is unavailable for startup, the system operates in uniprocessor mode rather than attached processor mode. During the system startup process, the use rid designated in D8KSYS is
automatically logged on as the primary system operator; he must have
class A command privileges. This process matches the userid supplied by the SYSOPR macro (used in system generation) with the user directory.
If there is an incompatibility between userids, then the automatic
operator logon process is aborted and system operational control is
given to the first user with privilege class A who logs onto the system. In the case of an automatic logon failure when a privilege class A user explicitly logs onto the system, where the system console is either
a 3210 or 3215 (or a 3138, 3148, or 3158 console in printer keyboard mode), the user must protect the security of his password as there are
no print-masking or print-inhibiting features on these devices.
After the operator has logged on, V8/370 prompts him for the type of
system start desired (whether this is a warm start or not).
At this point, the system is ready for normal use. The operator can
now: • Establish a message of the day to be issued to users when they log
on. • Enable communications lines to permit users to log on.
The Time-of-Day (TOD) clock provides an accurate measure of time, independent of system events or activities, and makes accurate
measurements available for programming applications. When system power
is turned off, the clock value is lost on some System/370 models. Once the time-of-day (TOD) clock has been made operational through the SET CLOCK instructions and the TOD ENABLE SET switch, it is incremented at a
constant rate. This timing operation is not affected by: 10 V8/310 Operator's Guide

• Any normal activity or event in the system • Wait state • Stopped state • Instruction-step mode • Single-cycle mode • Test model • System reset • Initial program load procedure
If TaD clock hardware errors occur, the System/370 hardware posts a
machine check and CP enters a disabled WAIT state.
The current clock value can be obtained by using the System/370 STORE CLOCK instruction, which causes the current clock value to be stored in
the storage location specified in the instruction. Thus, virtual
machines can use the value of the TOD clock for any purpose that their
users desire. However, virtual machine users cannot set or modify the
TaD clock.. V!/370 uses the TaD clock for establishing certain
accounting records for the virtual machines as well as queueing and
prioritizing tasks for CP and virtual machine operations.
The privileged System/370 instruction, SET CLeCK, sets the clock to a
specific value. If certain operating or program conditions exist, CP executes this instruction when the system is initialized. When this
instruction executes, it replaces the current clock value by the value
specified in the instruction. The SET CLOCK instruction changes the
clock value only when the TOD ENABLE SET switch is enabled.
If the inst?llation is configured with an attached Frocessor, it may be necessary 1n the initialization procedure to synchronize the TOD clocks. When this occurs, you may be requested to ready the "TOD ENABLE SET" key twice; once to set the clock on the main processor and once to "SET and SYNC" the clock on the attached processor. If the clock value
has previously been established for the main then only one proapt message will be issued. Note, that the TOD Enable Set key is
or'd to the other processors' TaD Enable SET key. This permits the
setting of the clock from either processor. If the low-order 32 bits of
the TaD clock are out of synchronization, a TOD Sync check will be
received. Again, you will be requested to synchronize the TOD clocks by pressing the TaD Enable Set key.
Details on those segments of V!/370 initialization that
only to attached processor applications are detailed at the System Initialization topic.
are unique
end of the
If the clock needs to be set, CP prompts you to enter the date by
issuing the message: SET DATE !!/DD/YY: You should then enter the date. CP then requests the time: SET TI!E HH:!!:SS: You should then enter the time. IThe current clock value is lost when the time-of-day microdiagnostic
tests are being run, or when system power is turned off. Sectiori Initiating Vft/370 Operation 11