what is meaning of rotary compressor ac of alto

maruti alto is claiming of ac with rotary control what does it mean does it help anyway in controlling 800 cc alto engine when run with ac

By rotary control they are probably referring to the blower fan speed knob - this would be a rotary type instead of a sliding type. Both types do exactly the same thing and apart from physical structure and user preferences (some like sliding, some rotary), they don't have any advantages/disadvantages over each other.

The rotary compressor refers to the type of compression design used in the AC system

There are basically two types

Rotary and scroll type.

More info here

@Rohit-the nomenclature seems to fit the switches as well, but that is not the case here.

Binoy, From what is quoted in the first post 'rotary' is referring to the control part only, so the original explanation by Rohit holds.

The compressor related information  can be seen as 'added info'. Nothing confirms or refutes the fitment of rotary compressor in Alto.