I am curious about the ability of anonymous tracing to map function coverage of IO Nexus driver fucntions during boot up. From what I see as an example at the following web page, http://clem.uk/~gavinm/dtrace/anontracing.html it seems that the earliest when dtrace is enabled during boot up is after nexus driver (e.g pcisch) is loaded.. load ''drv/isp'' id 24 loaded @ 0x12d6fb8/0x19837ec size 67632/56112 load ''drv/pci_pci'' id 25 loaded @ 0x12e77e8/0x199131c size 18712/4360 load ''drv/pcisch'' id 26 loaded @ 0x12ec100/0x1992424 size 85776/15416 load ''drv/sgsbbc'' id 28 loaded @ 0x1302ff0/0x199679c size 24792/648 load ''drv/ssm'' id 27 loaded @ 0x1301010/0x19960a4 size 8160/1784 load ''drv/dtrace'' id 7 loaded @ 0x1309738/0x1996afc size 74704/976 load ''tod/todsg'' id 30 loaded @ 0x131bb08/0x1996ed4 size 5072/176 installing todsg, module id 30. installing sgsbbc, module id 28. If this is correct, then are we limited in the ability to trace certain kernel driver functions(like IO nexus) during bootup? I would like qtrace to be able to map functions in the nexus driver code right from the time it starts loading. ALso, I believe dtrace would not be able to trace the functions in the IO nexsu driver during its unload (system shutdown), is that right? Thanks Pramod -- Pramod Hangal xt 41984 Cross Platform QE SSG, Sun Microsystems