public void deleteTask(jpvmTaskId tid) {
		if(tasks == null) return;
		jpvmTaskListRecord tmp = tasks;
		
		// Check head
		if(tmp.tid.equals(tid)) {
			if (iter == tmp) iter=tmp.next;
			tasks = tasks.next;
			num_tasks --;
			return;
		}
		// Check body
		while(tmp.next != null) {
			if(tmp.next.tid.equals(tid)) {
				if(iter==tmp.next) iter=tmp.next.next;
				tmp.next = tmp.next.next;
				num_tasks --;
				return;
			}
			tmp = tmp.next;
		}
	}