Powershell adding file sizes, unexpected result - powershell

Question

I am currently working on a powershell script to copy a random selection of songs from my NAS onto an SD card. As an added complication, I can have no more than 512 songs per folder and also obviously, need to stop the process before I run out of free space on the card.
I have written a nearly complete script (with reduced amounts of songs for testing purposes), but am struggling with keeping track of the total size of the files I have copied. As an example, a test run with a total of 112MB of files gives a recorded value (in $copied_size) of 1245. I don't know what that value means, it doesn't seem to be a realistic value of GB, Gb, MB or Mb. I am obviously missing something here. Any ideas?
Here is the script, I haven't put in the size restriction yet:
$j = 1
$i = 0
$files_per_folder = 5
$sd_card_size = 15920000000
$copied_size = 0
$my_path = '\\WDMYCLOUD\Public\Shared Music'
$random = Get-Random -Count 100 -InputObject (1..200)
For ($j=1; $j -le 5; $j++)
{
md ("F:\" + $j)
$list = Get-ChildItem -Path $my_path | ?{$_.PSIsContainer -eq $false -and $_.Extension -eq '.mp3'}
For ($i=0; $i -le $files_per_folder - 1; $i++)
{
Copy-Item -Path ($my_path + "\" + $list[$random[(($J - 1) * $files_per_folder) +$i]]) -Destination ('F:\' + $j)
$copied_size = $copied_size + ($my_path + "\" + $list[$random[(($J - 1) * $files_per_folder) +$i]]).length
}
}
Write-Host "Copied Size = " $copied_size

Answer 1

Here's a way to solve your problem using some more powershell-like patterns. It compares the current file to be copied with space remaining and will exit out of the top-level loop if that condition is true.
#requires -Version 3
$path = '\\share\Public\Shared Music'
$filesPerFolder = 5
$copySize = 0
$random = 1..200 | Get-Random -Count 100
$files = Get-ChildItem -Path $path -File -Filter *.mp3
:main
for ($i = 1; $i -le 5; $i++) {
$dest = New-Item -Path F:\$i -ItemType Directory -Force
for ($j = 0; $j -le $filesPerFolder; $j++) {
$file = $files[$random[(($j - 1) * $filesPerFolder) + $i]]
if ((Get-PSDrive -Name F).Free -lt $file.Length) {
break main
}
$file | Copy-Item -Destination $dest\
$copySize += $file.Length
}
}