On windows you can map a drive letter to a network drive and use the drive letter to access files, or you can specify the UNC name for the file. The advantage of a drive letter, aside from being shorter, might be that it makes your JSL less dependent on a network share that might get renamed. The advantage of the UNC name is that it makes your JSL less dependent on a drive letter that might not be mapped on another machine.
Right-click the network name and pick Map Network Drive...
So, open("F:\abc.jmp") and open("\\VBOXSVR\windowshare\abc.jmp") are the same file.
As Jim suggests, Mac is different. I can't help there.
Craige