An external drive is the same as an internal drive just not installed inside the case. Meaning you can use it in exactly the same way as an internal drive.
A backup drive is usually a zip drive designed to back up you hard drive and isn't used as a hard drive itself. It is usually in the form simalar to a floppy disk that the backup information is copied to. You can then use the backup disk and drive to reinstall all of your information from your original hard drive back to the hard drive in case of a virus or manually removing something that was needed for the system to run.
A USB flash drive is a type of external drive. If you meant external drive as an external hard drive, then no, there won't be any difference in the pictures. However, if you're archiving, I'd suggest an external hard drive, because they work best for archiving.
The main difference is size and speed, and do not forget prize. In addition, the fact that external disks are connected to the computer at all time may cause the disk to be infected. Therefore, I would recommend you to use a portable disk, and do a backup once a week or month.
backup
Purchasing an external hard drive would be the best and the most inexpensive way to backup your home data. You can purchase an external hard drive for around $70
If one is looking for a good storage backup drive for a laptop, there are many very good external drives that will provide this. Some of the higher rated ones are the Seagate Backup Plus and the Buffalo Ministation Thunderbolt.
Do you have backup software installed that is mapped to an external hard drive? The software might be automatically trying to backup your files, but the external hard drive is not plugged in.
No.
I use and recommend Handy Backup, it's easy and reliable backup software for home use.
If you store your backup of your C:\ drive (which is usually where all your files, photos, etc are stored) on another (logical) partition on the same physical drive (C:\) and this is where you store your backup, if the drive should fail you would lose both the original files AND the backup as well. This is because they both reside on the SAME physical drive. Buy an inexpensive thumb drive or external hard drive and store your backups there. This way is the C:\ drive fails, you still have your backup files (on the external or flash (thumb) drive).
One can perform a system backup several different ways. One can backup their system to an online service. You can also do a backup to an external hard drive.
You can copy data to an external hard drive to create a backup of files on your computer. The simplest option is to drag and drop from your computer to the external drive so that you have a copy. Backup software such as Apple's Time Machine does that automatically and can also keep track of different versions of a file so that you can undo accidental changes.
Backup software is not recommended since if your hard drive fails, your backup fails. It is best to get an external hard drive or to back up your computer in the cloud.