Windows FAT32 = 65,534
Windows NTFS = 4,294,967,295 (unlimited)
Max files using hash storage: one hundred and thirty-seven billion, four hundred and thirty-eight million, nine hundred and fifty-three thousand, four hundred and forty

Linux (uname -r to find ext):

ext2/ext3 = 10,000
ext4 = unlimited

// Test storage of multi files in multi folders
$oStorage = new HashFileStorage();
for($i = 0; $i <= 1000; $i++){
$sTestFilename = uniqid("store_");
$sTestFileText = "This file contains text for file: " . $sTestFilename;
$bSave = $oStorage->file_put_contents($sTestFilename, $sTestFileText);
error_log("Saving HashFileStorage file: " . $sTestFilename . " (" . var_export($bSave, TRUE) . ")");
}