grid in mm or inches says that the grid settings in the schematic/layout/library editor can be chosen in inches or if you prefer in millimetres.
up to 255 drawing layers --- EAGLE distinguishes between signal layers and drawing layers. The professional edition, for example, can have a maximum of 16 signal layers. And there are additional "non-electrical" layers, like some for the silk screen on the board or for solder stop mask and so on. There are some pre-defined drawing layers and there are free layers that can be used for any purpose in your drawing. The maximum number of all these layers is 255.
grid in mm or inches says that the grid settings in the schematic/layout/library editor can be chosen in inches or if you prefer in millimetres.
up to 255 drawing layers --- EAGLE distinguishes between signal layers and drawing layers. The professional edition, for example, can have a maximum of 16 signal layers. And there are additional "non-electrical" layers, like some for the silk screen on the board or for solder stop mask and so on. There are some pre-defined drawing layers and there are free layers that can be used for any purpose in your drawing. The maximum number of all these layers is 255.
