All drivers and devices in Linux are simply files or folders. Usually a link to them will appear on your desktop when needed. For example if you plug in an external hard drive or insert a DVD. If not if you look in /dev/ you will find everything.
How many can you put in your computer? Linux can support massive servers with hundreds of hard drives. I believe the mainline kernel supports up to 702 hard drives, although patches are available for up to 3904 disks. You're far more likely to run into hardware limitations than you will with how Linux handles hard drives.
LVM is a logical volume manager for the Linux kernel; it manages disk drives and similar mass-storage devices.
Almost all USB Flash drives conform to the USB Mass Storage specification, which is has been supported in the Linux kernel since the 2.4 series. You would really have to go out of your way to find one that doesn't work in Linux. Any drive from Sandisk, Kingston, Lexar, or Samsung, as well as most el cheapo drives you can buy on eBay will work.
You may be thinking about ddrescue which is a Linux CLI tool for recovering damaged files and drives.
I'm assuming your using Windows. You can see the drives by double clicking "My Computer" on your desktop. From there you can double click on the drives to see the contents. If you can't see the other drive, make sure its installed properly.
Historically, hda was used for IDE drives and SDA was used for SCSI drives. Today, regardless of physical interface, all drives are treated as SCSI devices.
Usually some distribution of Linux. Go to NASA's supercomputing section of their website and you will see that their 2 supercomputers run SUSE Linux. There are other examples, but historically Unix or Linux are most popular.
I suggest installing Windows, and then Linux (preferably on different physical hard drives). When Windows is installed it tends to overwrite the boot partition, making it difficult to boot linux afterwards.
The original iPod Linux project is inactive, but there are other projects out there that still work on the iPod nano. See the related links below.
PS (see "man 1 PS") in Linux is a program that generally comes with the operating system that allows you to see information about the running processes. pstree is a program that lets you see the processes as a tree, to see which process started which other process, for example.
Linux is not a company.
A person can find reviews on SCSI hard drives from several different places. Some of these places include CNET Reviews, Linux Lookup, and The Tech Report.