The way people talk about syscalls depends on your context&#x2F;point of view. For example doing `open()` for the system is duration, because it does the work of opening a file. For the app, it may as well be latency - how long you&#x27;re stopped before the file is opened.<p>Since the app doesn&#x27;t actually execute the open code, it is latency -&gt; from stimulation (called), to response (returned) is the latency of file access. For the system code latency would be waiting for the disk controller. For the disk controller latency would be waiting for the heads&#x2F;platters.