A sewing machine includes a sewing machine body formed with a cassette mount, a thread cassette having a supply of thread and detachably attached to the cassette mount, and a moving speed limiting unit limiting a moving speed of the thread cassette when the thread cassette is attached to the cassette mount. The control box has the front panel thereof extending two pivotal connectors to join two docking boxes containing a data record loader and a compact disk burning record device respectively. If the pointer is on the vertical slider, the invention ignores left and right mouse movements. The present invention also provides social benefit by integrating a first individual’s social network for uses in communication with the first individual’s social network and in recalling the first individual’s social network. When assembling the magnet connector, the magnetic body is partly attracted in the receiving cavity of the base body by the magnet and then is assembled to the magnet connector with the magnetic poles thereof being uniformly arranged in a kind of only certain way after mass production of the magnet connector. The processor analyzes the acceleration input data to determine a target gear ratio.