Osmosis returns smaller .osm file

Hi All,
I’m new to OpenStreetMap and have an interest about it.

I want to ask about Osmosis.
I have an .osm file, called melbourne.osm (12,642,813 bytes).

Then, I run that file through Osmosis using this command:

The result that I get is map.osm file which is just 10,543,105 bytes which smaller rather than the original OSM file.

Could someone explain to me about this?
Does it mean that Osmosis remove some data from the .osm file?

Thanks in advance

Hi and welcome :slight_smile:

I suspect Osmosis leaves any dates out by default (node and way last update dates) while reading the melbourne.osm.