Tray Disk Free will display numerically (unique to this program as far as I know) the free space of your hard drive on system tray bar, and can use of a few command line options.
A Disk Scheduling Simulator tool. With an intuitive GUI interface and command line functionality. Built using both VC and VB. Currently supports SSTF,LOOK,CLOOK,SCAN and CSCAN algorithms. Rotational latency is also optionally supported.