TN.140.PBHSetVol - This note explains PBHSetVol, and why its use is not recommended. PBHSetVol, like SetVol and PBSetVol, allows you to set the current default volume and directory to be used with subsequent File Manager calls. Unlike SetVol and PBSetVol, though, PBHSetVol lets you specify the volume and the directory separately, using the ioVRefNum and ioWDDirID fields.