Is there a way to use a laptop as a physical console?
Solution 1:
Yes, actually: see this USB-to-KVM thingie. It is rather expensive, but does exactly what you want.
If it wasn't so pricey, I'd have one in my bag.
Solution 2:
Depending on your server, it may perform Console Redirection over an inbuilt serial port; by using a USB-to-Serial adapter (if your laptop does not come with a serial port), you can get access to POST messages and the BIOS by using serial terminal emulator program ('screen' works well for this task, if you're unix friendly).
Your server may also support Serial Over LAN, accessible using IPMI tools talking to the server's Baseboard Management Controller. After configuring the BMC appropriately, you should be able to obtain access to the console over the wire.
Solution 3:
Another option (though it's also expensive) is an IP-KVM.
It does pretty much what the name suggests, which is allow you to control the computer over ethernet, generally by presenting an interface similar to a VNC server, either through a puprose-specific application, or a web interface. An advantage is you don't have to be at the computer to control it though.
I have seen them for less than the device mentioned above, but never for less than a few hundred dollars.
Unfortunately, converting a VGA signal back to digital is electronically non-trivial, and then the compression required to sent the converted signal over ethernet or usb is programatically non-trivial, and all of these things are low volume, so high prices are the unavoidable result.
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