Drawing current from motherboarad

[Xrib]

I'm drawing .5Amp and 4.5V from a PS/2 port directly from my motherbaord
for powering a USB gadget
Is it harmful for any of the components?
I checked and the PS/2 does give out 4.5V and .5Amp

 

[molletts]

The standard PS/2 port spec says that the port should be able to supply 275mA at 5V so technically you're overloading the port. Different implementations will, of course, vary in their capabilities.

Can you not draw power from a second USB port (assuming the one the device is plugged into doesn't provide sufficient)? USB 2 ports are normally rated for 500mA at 5V so you should be able to get enough. (Some external hard drives come with a USB->power lead in addition to the main data cable for precisely this reason.)