An apparatus includes a unit that uses a head with spaced read and write portions to write and read information to and from an information storage medium. According to one feature, a desired position for the write element is converted into a position for the read element as a function of a polynomial. According to another feature, the unit uses the head to write and read back selected information in order to determine compensation information, the receiving unit subsequently effecting writing of information with the head as a function of the compensation information. On a more specific level, the unit can removably receive a cartridge that contains the information storage medium.