Jumpshot-4 is the visualization program for the improved scalable logfile format, SLOG-2, which provides a hierarchical structure to store a large number of drawable objects in a very scalable and efficient way for visualization. The new scalable logfile format allows the display program to provide functionalities never made possible before. Level-of-detail support through preview drawables which provides high-level abstraction of the details without reading in huge amount of data into the graphical display engine. New Jumpshot allows seamless scrolling from the beginning till the end of logfile at any zoom-level. In addition, new functionalities like dragged-zoom, grasp and scroll, instant zoom in/out, easy vertical expansion of timelines, cut and paste of timelines are available as well. A new search and scan facility is provided to locate the hard-to-find objects in very large logfile. Also, the histogram module based on user selected duration provides a convenient and graphical way to analyze the statistics of logfile, e.g. easy detection of load imbalance among timelines. The new legend table makes manipulation of the different categories of objects easy. The new viewer also provides an integrated logfile convertor for all known SLOG-2 convertible trace formats, like CLOG, RLOG, and UTE, and it attempts to conform to the standard Look and Feel that is expected by most users.