Total Commander supports setting a speed limit for file copying. This is super-useful for handling stuff without stressing a mechanical drive too much. Do we have such a thing in DOpus?
Also, when replacing files, I'm kind of missing Total Commander's "append" and "overwrite smaller files" options.
I'd expect making the copy take longer is more stressful to a drive than writing the data as quickly as possible while the drive is already spinning and the heads are already where the data needs to go. Is there any science behind that idea we can look at to change my mind?
Speed throttling is only an option with FTP transfers at this time.
Appending is also an option with FTP, where transfers are often interrupted and need to be resumed. It almost never makes sense, and can be dangerous if misused, on local or network-drive file copies, so we don't offer it for them. Why do you find yourself needing it?
Opus has a few ways to replace files based on date, size or content but I don't think we currently have one for the size being smaller (only different). Updated files are often smaller than old ones (or vice versa) so it's rarely a criteria people need, at least in our experience. It could be done using scripting, however.
By the way, it's better to ask one question per post unless things are closely related (see the FAQ about this for our reasoning).
You are probably correct regarding the hard disk. Let me rephrase: I would like to limit the copying to 2 MB/s so that I can in the same time execute programs and have a decent response time from the HDD. This is NOT healthy for the disk as it will do a lot more work (they're not good at multitasking at all) but may be convenient sometimes. In any case, it's a nice-to-have at best.
Ah, good to know that the FTP has it! 
. As for the other options, well, I'm not that much in love with them and haven't used it that often. Scripting is a really interesting thing that I will look more closely into today . So far I like DOpus!
I too was wondering if there was a way to put a limit on transfer speed. My reason is specifically for network activity. If I'm pushing several gigs of data over a network, it tends to negatively effect network activity. Optimally it would be amazing if you could set transfer speeds individually for local and network transfers.
+1 for this request. I too have a need for setting a limit on the copying speed. I just copied about 60 GB to my sole hard drive, from which I also run Windows (an Asus VivoPC which can only contain one 3.5" drive). However, Windows became rather unresponsive while copying because the disk was heavily used. If I could set a limit I assume that Windows will be more responsive. TBH, I think that an advanced file manager as DOpus should include this option.
I'm wondering if this is still on the list of things to add. In my case, I am on a network that transferring large amounts of data at high speeds has the unfortunate side effect of shutting down the router. I think it's an overheating issue, but from what I've tested if I keep transfer rates around 2 mb/s things work fine. Going faster than that ends up in having to powercycle the router, and having to go back and verify the files to make sure nothing got messed up when the router went down.
Wouldn't it make more sense to fix your router? What if something else sends data too quickly over it? Fixing the router seems easier than getting every piece of software every written to implement a slow mode.