The default installed Solaris 9 x86 is not supported by the mouse wheel, which is more painful.
Find the repost article in Cu, recommend a software
software:
http://www.tools.de/solaris/ps2wheel/
PS / 2 Wheelmouse Driver for Solaris x86
Download The Solaris X86 PS / 2 Wheelmouse Driver (21kbyte; 2004-7-29). The Driver Works with Solaris 8 x86, Solaris 9 x86 and Solaris 10 (Beta) x86 and is intended to be used with the solaris x11 server xsun. Uncompress and install the package as user root bunzip2 Toolsps2w-1.6-i386.pkg.bz2
Pkgadd -d Toolsps2W-1.6-i386.pkg
CONFIGURE THE MOUSE WITH THE COMMAND KDMCONFIG. SELECT The "Built-in PS / 2 Wheelmouse" Entry with the appropriate Mouse Protocol in The Pointing Device Submenu.
