Modern external computer data storage technologies (DAS, or Direct Attached Storage) run the gamut from USB hard drives, to optical discs (yes, still), to USB thumb drives, to the latest, greatest NVMe SSDs in high-speed Thunderbolt or USB 4 enclosures. PCWorld has been reviewing external storage since the 1980s and the era of floppy drives, though these days we stick with SSDs and the occasional hard drive. Everything else seems, well… quaint. Not to mention, drearily slow. What does PCWorld look for in an external storage device?CapacityGenerally speaking, more capacity is better, but determ…