Often as a developer, for testing disk performance, or perhaps your internet or network connection speed, you need to generate a large file of a specific size. Windows includes a utility that allows you to quickly generate a file of any size instantly.
This is a command line (DOS) utility, so firstly, open a command prompt (as an administrator if you need to write to protected folders).
To launch a command prompt, hit start and just type
command. You'll see "Command Prompt" appear as the closest match (Remember to right-click and choose "Run as Administrator" if you need admin priviledges). Alterntaively, use the key combination:
R, and type
cmd.exe to launch a command prompt.
Run the following command:
fsutil file createnew <file> <size in bytes>
For example, this command will create a 1GB file called
1gb.test in my temp folder:
fsutil file createnew c:\temp\1gb.test 1073741824
Note: the size of the file is specified in bytes. So, you'll need to be specific about the value you choose if you need a specific size.
Googling the converted value (e.g.
100gb in bytes) will give you a result, but to avoid answers with exponents, here are some pre-calculated equivalent values:
|Size||Size in Bytes|
If you don't like using the command line there are various GUI utilities out there that can also do this for you:
Dummy File Creator: http://www.mynikko.com/dummy/
Disk Tools Toolkit: http://www.soft.tahionic.com/download-file-generator/