Single filter and multi-filter endolumenal methods and systems for filtering fluids within the body. The services on the OLTP system are designed to accomplish a specific task, for example, update a user’s bank account balance following a debit or credit. According to the amount of the liquid stored in the reservoir, an immersed degree of the level indicator into the liquid may become different. The feeder presses the marker against the sheet to attach it. In another aspect, the write driver generates the write current corresponding to one of a set current pulse and a reset current pulse, and at least one of the set current pulse and the reset current pulse is gradually increased.