The Raritan Blog

KVM Switches & BIOS-Level Access – Part II

Jessica Ciesla
February 24, 2021

A previous blog discussed the fundamentals of the powerful “BIOS-Level Access” that KVM-over-IP Switches like the Raritan Dominion KX Switches provide. This blog covers more advanced features including: (1) virtual media usage in the BIOS, (2) special KVM features that we have implemented over the years, and (3) BIOS changes that are sometimes necessary to support BIOS usage by KVM switches.

Virtual Media in the BIOS

Virtual Media is a KVM-over-IP Switch function to mount various media such as USB drives, DVD drives, and ISO images from the user’s laptop/PC to a remote computer through the computer’s USB ports. The user can then transfer files, install software, and more. A really nice feature is that these virtual media drives are available in the BIOS, so an IT administrator can even boot an OS from the virtual media drive.

Special KVM Features for BIOS

When we initially implemented virtual media in the Dominion KX II many years ago, users reported problems with virtual media drives in the BIOS, as well as problems with using the keyboard and mouse in the BIOS. We discovered that some BIOS versions did not support USB virtual media, keyboard, and mouse in a standard way.
To solve these issues, we created a few innovative solutions for our Dominion Switches:

  • USB Profiles. To support the varying USB implementations of different computers, we’ve developed a large number of USB profiles, which are specific combinations of USB settings to support particular computer manufacturers, computers, operating systems, and BIOS. These are named accordingly, for example, “BIOS Dell Poweredge” and “Mac USB-C.” Users can select a USB Profile based on the computer they are accessing.
  • Dual USB Computer Interface Modules (CIM). These server dongles connect to a remote computer via two different USB plugs and ports. We’ve found that many BIOS support virtual media better when the keyboard and mouse are connected via one USB plug and virtual media is on the other USB plug. These CIMs also support advanced features such as smartcards and digital audio over USB. We recommend the Dual USB CIMs for virtual media at the BIOS level.
  • Quick Sense Video Mode. The Dominion KX III has a video setting for the KX to more quickly lock on to the computer’s video signal to make sure the user can enter the BIOS. This option is especially useful for entering a target server's BIOS configuration right after a reboot.
  • Mouse Synchronization Modes. Our KVM switches support various mouse modes if the recommended Absolute Mouse Mode doesn’t work in the BIOS.

With these new features, Raritan’s Dominion Switches now support virtual media in the BIOS and a wide variety of BIOS from multiple computer manufacturers.

BIOS Changes for KVM Switches

While we are on the topic of the BIOS, it is good to mention that sometimes BIOS settings are needed to support the connection of KVM switches.  I have come across these situations in my experience:

  • Wake-up on USB. Sometimes BIOS changes are necessary to allow the USB keyboard and mouse to wake up a computer.
  • Laptop KVM Connection. Sometimes the BIOS won’t show on the external video port of a laptop unless a BIOS option is set. The laptop’s video port may also need to be mirrored.
  • Remote Power Control. Sometimes the BIOS needs to be changed to cause a computer to boot up when the power is cycled.

More information on Raritan KVM switches can be found in the documentation and online help, available on the Technical Support Pages for each product. For more information on your computer’s BIOS, contact the documentation from the manufacturer.