🚀 go-pugleaf

To get the volume name of the current startup disk (ie the disk on which the
current System Folder is) in C, use the working directory reference number
of the system folder contained in BootDrive ($210), and then GetVolInfo:

    ParamBlkRec paramBlock;
    paramBlock.ioNamePtr = startupVolName;
    paramBlock.ioVRefNum = *(int *)0x210;
    paramBlock.ioVolIndex = 0;
    PBGetVInfo(&paramBlock, 0); /* returns OsErr */

Note that since BootDrive is an HFS global, this code will fail under the
64K ROMs... but who cares about them anyway :-)  If you want MFS, look at
Inside Mac II-108, which tells you to GetVRefNum of SysMap which returns the
VRN of the system startup volume.
-Justin