Connecting power sources in series or parallel?
In series, you would have 3 volts at 100 mA - the supply with the lowest rated current will limit the usable current you can draw from the combined supply.

In parallel, you have a problem - the 2 volt supply will try to pull the 1 volt supply's output up to 2 volts.  If the 1 volt supply is capable of sinking current, it will try to pull the 2 volt supply down to 1 volt, and a large current will flow between the supplies - the resulting voltage and available current will depend on the nature of the two supplies.