Sun Microsystems 3.0.0 user manual Processor tab

Models: 3.0.0

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3 Starting out with VirtualBox

Enable ACPI VirtualBox can present the Advanced Configuration and Power Interface (ACPI) to the guest operating system for configuring the virtual hardware. In addition, via ACPI, VirtualBox can present the host’s power status information to the guest.

ACPI is the current industry standard to allow operating systems to recognize hardware, configure motherboards and other devices and manage power. As all modern PCs contain this feature and Windows and Linux have been supporting it for years, it is also enabled by default in VirtualBox.

Warning: All Windows operating systems starting with Windows 2000 install different kernels depending on whether ACPI is available, so ACPI must not be turned off after installation of a Windows guest OS. Turning it on after installation will have no effect however.

Enable I/O APIC Advanced Programmable Interrupt Controllers (APICs) are a newer x86 hardware feature that have replaced old-style Programmable Interrupt Con- trollers (PICs) in recent years. With an I/O APIC, operating systems can use more than 16 interrupt requests (IRQs) and therefore avoid IRQ sharing for improved reliability.

Note: Enabling the I/O APIC is required for 64-bit guest operating systems, especially Windows Vista; it is also required if you want to use more than one virtual CPU in a virtual machine.

However, software support for I/O APICs has been unreliable with some operat- ing systems other than Windows. Also, the use of an I/O APIC slightly increases the overhead of virtualization and therefore slows down the guest OS a little.

Warning: All Windows operating systems starting with Windows 2000 install different kernels depending on whether an I/O APIC is available. As with ACPI, the I/O APIC therefore must not be turned off after installation of a Windows guest OS. Turning it on after installation will have no effect however.

3.7.2.2 “Processor” tab

On the “Processor” tab, you can set how many virtual CPU cores the guest operating systems should see. Starting with version 3.0, VirtualBox supports symmetrical multi- processing (SMP) and can present up to 32 virtual CPU cores to each virtual machine.

You should not, however, configure virtual machines to use more CPU cores than you have available physically.

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Page 48
Image 48
Sun Microsystems 3.0.0 user manual Processor tab