App needs to write files from one driveX:\folder to another different driveY:\folder

[LorinM]

What methods should I use to get the fastest copy ?

I have many large files I need to copy.

Pass to some external program or use certain APIs with special settings ?

[fafalone]

You could use lower level APIs but I don't think the API being a few ms faster starting the copy will have any noticeable impact compared to the time it takes the physical disks to read and write. Have you found any programs that copy faster?

[LorinM]

I thought I read decades ago that ...
(1) there is a API fast copy that works on Vista and beyond
(2) that windows does some copy double buffering that can be turned off
(3) that using the correct copy buffers size for read and write related to the disk physical sector size was important
(4) that the size of the copy buffer for read and write is important.
(5) offloading the main app by passing the copy process to say an ActiveX.EXE

How significant are these and other factors ?

[fafalone]

Find a program that actually copies faster, if one exists, then look at how.

A lot of things that might have mattered for 80s or 90s hardware don't for modern drives.

Maybe if you're trying to copy while under heavy load you could increase the priority of the process/thread above whatever is hogging the CPU/disk.

[BenJones]

You chould ue an array andd copy the file in blocks I seen a lot of this done in the old Qbasic programs and some were fast. your other option if to write a low level code in C and call it from a dll I am not to sure but you may also ue the api functions WriteFile and ReadFile, or you chould save your self some time and make a pipe to xcopy on windows that does almost what you need and more.

[Zvoni]

I would use CopyFileEx-API within an ActiveX-DLL
1) It would run in its own Thread
2) you could pass the callback via Event back to the calling Program, informing the user about progress

[fafalone]

Dont need an activex exe for something like that, just The trick's multithreading module. (Or of course, tB is thread safe and requires no hacks to call CreateThread)

[VanGoghGaming]

Being thread-safe doesn't mean much, synchronization is still a major pitfall of threading. By comparison, ActiveX EXEs are a breeze.

[fafalone]

This isn't many threads trying to coordinate the same task, it's just a single thread spun up for a single task.

Maintaining a whole separate exe, active x no less, isn't really optimal imo. Most of us get by with a DoEvents to update the GUI and check for cancel clicks in the copy callback.

[Elroy]

One question that isn't clear to me ... are these files being copied from the same "box", just different drives, or:

• Are they being copied from different drives or folders on a server?
• Are they being copied from two entirely different "boxes", possibly locally-to-server (or vice-versa)?

The answers to those questions can make a very large difference for the correct answer to your question.