Rack width includes the rails/ears. That’s where the extra inch you’re referring to comes from. The actual size of equipment you can slide between the rails and inside the rack, not including ears, is about 17.75" for 19" racks and about 8.75" for 10" racks. That is indeed half the width. Or at least within 0.125", but I don’t know how accurate these numbers really are.
MicroATX very much cannot fit in this 10" rack.
Equipment that is “half-rack” or “half-width rackmount” tends to be primarily intended to mount two devices side by side on the same row of a 19" rack, but also can often be mounted in a 10" rack by attaching ears to both sides.
Rack width includes the rails/ears. That’s where the extra inch you’re referring to comes from. The actual size of equipment you can slide between the rails and inside the rack, not including ears, is about 17.75" for 19" racks and about 8.75" for 10" racks. That is indeed half the width. Or at least within 0.125", but I don’t know how accurate these numbers really are.
MicroATX very much cannot fit in this 10" rack.
Equipment that is “half-rack” or “half-width rackmount” tends to be primarily intended to mount two devices side by side on the same row of a 19" rack, but also can often be mounted in a 10" rack by attaching ears to both sides.