Error while running diskspd - testing

Question

I am running diskspd.exe tool which you can download from:
Diskspd Utility: A Robust Storage Testing Tool (superseding SQLIO)
https://github.com/Microsoft/diskspd
Operating system: Windows 2016 standard
I first get this:
D:\Diskspd\amd64fre>diskspd.exe -d15 -o4 -t4 -b8k -r -L -w50 testdiskspd.dat
Error opening file: testdiskspd.dat [2]
Error opening file: testdiskspd.dat [2]
Error opening file: testdiskspd.dat [2]
Error opening file: testdiskspd.dat [2]
After 15 seconds I get this:
There has been an error during threads execution
This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.
At the same time I get following pop up window:
I have write permission in folder D:\Diskspd\amd64fre\. I tested this by creating a .txt file.
This is what I can see in my windows log.
Faulting application name: diskspd.exe, version: 0.0.0.0, time stamp: 0x54b9a313
Faulting module name: msvcrt.dll, version: 7.0.14393.0, time stamp: 0x57899b47
Exception code: 0x40000015
Fault offset: 0x000000000000c2c2
Faulting process id: 0x4b40
Faulting application start time: 0x01d3e2437778fe7f
Faulting application path: D:\Diskspd\amd64fre\diskspd.exe
Faulting module path: C:\Windows\System32\msvcrt.dll
Report Id: 2190f963-f533-4805-b23a-e3224c56e72d
Faulting package full name:
Faulting package-relative application ID:
Any suggestions?

Answer 1

I needed to provide the file size switch and a value. Then it ran fine. From the document it was not clear that it was a mandatory parameter.
D:\Diskspd\amd64fre>diskspd.exe -d15 -o4 -t4 -b8k -r -L -w50 -c1G testdiskspd