adapter, and floppy). The types of network adapters are covered in the next chapter,
but for now know that a legacy network adapter is an emulated network adapter
instead of the synthetic network adapter that utilizes the VMBus. Typically, you never
want to use the legacy network adapter except for a very specific use case, booting over
the network.
Figure 2. 4 The BIOS configurations possible for a generation 1 virtual machine. The
boot order can be changed using the Move Up and Move Down buttons.
Many other system devices are enabled in the guest operating system through the
virtual motherboard provided by Hyper-V. They can be seen in the System Devices
section in Device Manager (devmgmt.msc), but typically you won’t interact with these
items.
WHAT ABOUT THE TIME?
A physical motherboard has a small battery and a real-time clock (RTC) to track
time. But the way most operating systems work is to read the time from the RTC
at startup and then use their own internal routines to calculate passed time. The
problem for a virtual machine is that the routines used to calculate time do not
work correctly, because of the way virtual machine resources are delivered, which
means time drifts in a virtual machine.
To solve this problem, Hyper-V uses a time synchronization integration service
that keeps the time correct within the virtual machine. You could see some time
anomalies when a virtual machine is first booted or resumed from a saved state or
checkpoint (point-in-time saved view of a virtual machine), but these should
quickly be resolved after the time synchronization integration service loads,
which will correct the issue. Even if the virtual machine is in a different time zone
or is part of a domain that synchronizes time from domain controllers, you should
leave the time synchronization integration service enabled. The time
synchronization service will work well with other time sources. Run the w 32 tm
/query /source command to check the time source for your operating system. A
Hyper-V virtual machine should show the following:
C:\>w 32 tm /query /source