harddisk

With PowerShell

param (
    [int   ] $sizeInMB    = 100,
    [int   ] $chunkSizeMB =  10,
    [string] $filePath    = "$env:temp\file"
)

$chunkSizeBytes = $chunkSizeMB * 1MB

$bytesToWrite = $sizeInMB * 1MB
$chunks = [math]::Ceiling($bytesToWrite / $chunkSizeBytes)

$byteArray = new-object byte[] ($chunkSizeBytes)
$startTime = Get-Date

$fileStream = [System.IO.File]::OpenWrite($filePath)

for ($i = 1; $i -le $chunks; $i++) {
#
#   Write the chunks

    if ($i -eq $chunks) {
      #
      # Last chunk, write remaining bytes only

        $remainingBytes = $bytesToWrite % $chunkSizeBytes
        if ($remainingBytes -gt 0) {
            $byteArray = new-object byte[] ($remainingBytes)
        }
    }

    $fileStream.Write($byteArray, 0, $byteArray.Length)
#   write-host "Chunk $i written ($($byteArray.Length / 1MB) MB)"
}

$fileStream.Close()

$endTime = get-date

$timeTaken = $endTime - $startTime

write-host "File created: $filePath"
write-host "Size        : $sizeInMB MB"
write-host "Chunk size  : $chunkSizeMB MB"
write-host "Time taken  : $($timeTaken.totalSeconds) seconds"