I’ll try to make this as easy to understand as possible. There are way too many websites out there that make assumptions about the “average” person.
I’m not aware of any USB drives that can be treated like internal drives. Even if they exist, I’m focusing on those used as external drives. I’m covering flash drives, SD cards, hard disk drives (HDDs) and solid-state drives (SSDs).
Over the years, flash drives have been called all sorts of things, with confusing labels to match: Jump drives (with or without a space between the words), flash disks, flash drives, memory sticks and thumb drives. Those are just the terms I can remember.
I believe SD cards were originally designed for cameras, but I could be wrong. When you look for an SD card today, you’ll most likely end up with a micro SD card with an adapter. Micro SD cards are better suited for cell phones and tablets.
External HDD enclosures tend to double as enclosures for SSDs as well. I’m talking about the 2.5-inch form factor, commonly used in laptop computers. SSDs started off small but are now sufficiently large for most uses. Today, a 120-gigabyte SSD costs around USD $20.
Flash drives and micro SD cards continue to grow in capacity. I’ve had various sizes of both and I currently use a 256-gigabyte micro SD card more often than the 32-gigabyte flash drive I’ve had for a long time. 256 gigabytes is more than I allow for the Windows 10 partition on my HDD, which I shrunk to 100 gigabytes shortly after installing it.
While USB drives are most often used for storage, you can run operating systems from them with the right computer configuration and the right software.
There are multiple software titles that can create bootable USB drives, but I’m only mentioning those I’m familiar with and have used in the past. For Windows, it’s Universal USB Installer and Rufus. Yes, there are more but again, I’m not familiar with them.
For Linux, there are more than I’m familiar with as well. Most of the distributions have one title or another preinstalled.
If you want a persistent installation, Universal USB Installer on Windows works well enough, provided the Linux distribution supports persistence (most Debian and its derivatives like Ubuntu and Linux Mint support it). I prefer mkusb on Linux Mint. I’ve tested it with a flash drive and a micro SD card and it works for both, but I don’t have a USB HDD or SDD to test any further.
You can install the distribution of your choice on one USB drive or another, use it to install the distribution on an internal drive, or run it as a persistent distribution on the USB drive without installing it. Linux Mint runs well from my micro SD card, even though it’s much slower than on my internal drives.
You can find most distributions at DistroWatch.com. If you have no experience with Linux distributions, take your time and check out the most popular ones. Your computer most likely has a 64-bit processor (unless you have a computer more than 10 years old). You should always install the 64-bit version of a distribution to go with it.
Or whatever it’s called these days. When you boot up your computer, there are hot keys you can use to access the BIOS before the installed operating system boots up. On all the computers I’ve used, it’s F10. Others use F2 or the DEL key.
When you get into the BIOS, the item that shows for your USB ports might come up as anything. On the laptop computer I’m using today, it shows “USB Diskette on Key/USB Hard Disk”. If I always want either a flash drive or micro SD card to boot up first, I have to move that to the beginning of the UEFI settings and the beginning of the legacy settings. It can only be used to boot whichever one is recognized first while booting up.
Some computers with other BIOS software than mine will let you choose which drive to boot up from there. On my computers, I have hit F9 while booting up to make an alternate selection. When I have my micro SD card in the slot, it’ll appear as “USB Hard Drive (UEFI) Generic - SD/MMC/MS Pro (Generic - SD/MMC/MS Pro)” (no, I didn’t mistakenly type it twice) and “USB Hard Drive Generic - SD/MMC/MS Pro”.
In no particular order:
This is all simple for me but it could be confusing for you. Feel free to ask me any questions you might have. Having a “live” Linux distribution can help you fix a regular Windows or Linux installation on an internal drive, with or without persistence. Someday, an internal drive may no longer be necessary.
Newer Android phones (like mine) and computers have USB-C connectors. Some computers may have old USB connectors as well. I don’t know if any phones or computers support the new USB4 protocol standards, but they’ve been out for more than a year.
The USB4 protocol standards dictate a minimum of 20 gigabytes for transfer speed, up to 40 gigabytes in certain situations. That’s nearly a thousand times faster than USB2. I have two USB3 ports and one USB2 port on the laptop computer I’m currently using.
I don’t know how fast my SD card reader is, but I’m sure it’s much slower. It will never be as fast or reliable as solid-state drive at USB4 speed, which should be capable of running an operating system at full speed.