Abstract: A data storage apparatus has a data processing unit and a data store with a variable data storage structure. The data processing unit preferably divides received data into parts of at least two different sizes, stores the parts in the data store, generates connection information indicating how the parts are connected, and reassembles the parts when read from the data store. The connection information may be stored together with the relevant parts of the data.

Abstract: A method for transforming a logic format includes dividing a data segment into a main data segment having a main segment length and a sub data segment having a sub segment length shorter than the main segment length, allotting the main data segment and the sub data segment respectively to a main address and a sub address of a data storage unit, and defining a combination of a data format of a main data area defined by the main segment length and the number of main addresses and of a data format of a sub data area defined by the sub segment length and the number of sub addresses, as a logic format of the data storage unit. A determination is made at an arbitrary time whether the average of the length of all the data stored in the data storage unit is less than a threshold value. The sub segment length is shortened in response to a determination that the average length of all the data stored in the data storage unit is less than a threshold value.