specific timed - most cameras have timed exposures of 1, 2, 4, 8, 15 and 30secs, Olympus cameras almost uniquely extend this to 60secs which is very handy indeed for astrophotography
most cameras also allow dark frame thermal noise frames to be taken and subtracted automatically
in addition, Olympus has introduced some unique modes:
unlike BULB mode which is terminated on taking finger off the shutter button, Time mode requires a 2nd press of the shutter button so you don't have to use a remote shutter release or have your finger pressed on the shutter button during exposure
during BULB exposures, the image is able to be viewed on the LCD screen as it “develops” allowing you to terminate the exposure when you think the exposure is adequate