The Macintosh Portable was Apple Computer's first attempt at making a battery-powered portable Macintosh personal computer that held the power of a desktop Macintosh. Released in 1989, it was received with excitement from most critics but with very poor sales to consumers. Seemingly no expense was spared in the construction of the machine. It featured a black and white active-matrix LCD screen in a hinged cover that covered the keyboard when the machine was not in use. The mouse function was handled by a built-in trackball that could be removed and located on either side of the keyboard. It used expensive SRAM in an effort to maximize battery life and to provide an "instant on" low power sleep mode.