Whenever I am doing processor intensive tasks on my main computer
(i.e. burning a disc, encoding a movie, etc.), I will leave my computer
alone and not do anything else on it until the task is finished (I will
even go as far as shutting off my screen saver). I do this so that as
much processor power as possible can be devoted to performing the task,
and the task can be completed as quickly as possible–not to mention
that I hope to avoid introducing any errors into whatever task is being
I will, however, work on another computer in my house. If I need a
file from my main computer, I will access it over the network from a
mapped drive I have set up.
A friend has told me that accessing files through the network,
though not as intensive, is almost as bad as performing it directly on
my main computer while it is performing the burning or encoding. I
disagree, thinking that by accessing these files over a network, I am
using only the main computer NIC card and hard drive (and perhaps very
minimal processor power).
Can you please tell me which of us is correct?
Sure! You both are.
You see, it really depends on exactly what you’re doing. Some of
your scenario leads me to believe that you are right, and other
portions of your scenario have me siding with your friend.
I’ll give you the slight edge here because I can’t see your
friend’s “almost as bad” comment really coming into play.
I’ve actually “lived” this situation myself. I’ve set my desktop machine loose on some processor intensive task like video or audio encoding, and moved to my laptop to continue my work so as not to place any additional impact on the desktop. And of course, as luck would have it, there would be some file on my desktop that I need, so I copy it over the network to the laptop – simple as that.
Did it have any appreciable impact on the encoding or other work happening on my desktop? Not really.
And that’s the situation in most cases. In most cases, the impact of remote access across a network is negligible for all the reasons you mention: file access requires very little processor overhead, and similarly the network interface is also a very low processor-usage device.
So most of the time, I’m with you. There’s no appreciable impact.
Here are a few things that could, in fact, cause the remote file copy we’re talking about to have a noticeable, though still small, impact on whatever’s happening on your primary machine:
Encoding is more than just processor work. Those bits have to come from, and be written to, somewhere. So, by accessing the hard disk remotely in any way, it’s conceivable you could slow down the hard disk accesses required to do whatever it is you asked your primary machine to do. This can be exacerbated by a fragmented hard disk as well. While the task you set it to might have it calmly and quickly reading and writing from some locations on the hard disk that are near to each other, the remote access could cause the disk head to need to fly all over the media, slowing it down.
The disk might be slower than you think. As I discovered when my gigabit network wasn’t giving me gigabit throughput, disks themselves are occasionally the choke point for throughput. If the task you’ve set your machine to brings it close to that limit, then a remote access adding more work could push it over the edge.
The network card might not be as good as you might want. Certainly most don’t place an undue load on the processor, but that’s most. I’m sure that there are inexpensive interfaces that have a higher CPU impact than we might like.
You might be asking for a lot of data. Naturally, the impact on the remote machine, whatever it is, will likely be in proportion to the size of the files you’re accessing, and how you’re accessing them. A simple file copy of a small file? No problem. A larger file? Perhaps there will be a bit more impact. Accessing a database file hosted on that machine might well be a lot more file interaction that you expect.
So yes, there are scenarios where your friend might be somewhat right.
But in general and most commonly, the impact is negligible.
And certainly not “almost as bad as” doing whatever directly on the same machine. (Though even that is typically less than we think, depending on what “whatever” is.)