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This QuickFire article details what’s the difference between Physical and Logical in computers.  Physical is pretty much what it means, Physical for computers is the actual hardware itself.  For example, Routers, Sega Genesis, and SATA hard drives are all examples of physical hardware.  Logical is how the hardware is presented to the software that uses it.

     If that router for example, is simulated on my PC, it’s only a logical (or Virtual) router and not a physical router. It still works just like a physical router. The only difference is that the connections to it are made via software and the code that handles the routing is being executed on a machine that’s not a router. The code itself does not actually know or care that it’s being run on a PC.

     Going on that Sega Genesis example, should a team decide to program a game for it now as a fun challenge, they’d use the tools to do so.  Once they finish, they can put the final code on a cartridge for the system and insert it into the console to play. The finished code can’t natively run on a PC, but thru the concept of something known as an emulating, a PC user can use it.  The emulator is taking the role of the Sega Genesis hardware, but said emulator is translating the finished code to something that can be used on a PC.  To the finished code, the emulator is actually a Sega Genesis and is just running. 

      That emulation example goes deeper.  Modern day PCs (and Servers) have the ability to create virtual machines – special software that abstracts the hardware away and isolates the virtual machine from the rest of the physical machine.  These machines can run full blown Operating Systems inside them that can communicate with the host OS.  For example, I could use the demo version of Windows Server inside VirtualBox and take it for a test drive on a Windows 10 PC without disturbing my PC.   One thing to note: Should the software chosen to create virtual machines have bugs or vulnerabilities- ensure that they are patched so that the guest OS (such as Windows Server) can’t accidentally access the direct hardware.

    Finally, we get to SATA Drives.  Those are just hard disks that use the SATA protocol to communicate with the machine’s motherboard.   There are tools to virtualize these even too. Two potential ones are RAID — Redundant array of independent disks – and Virtual Hard Disks.      The Virtual Hard Disk is functional a file on a real true hard disk.  It can be mounted into a system via the OS to act are a real hard drive and be used just like one.  When one is finished it with, they can unmount the drive and just copy the file to go.   Virtual Machines will typically also use Virtual Hard Disks.

 RAID is a bit of a stretch.  It’s a collection of real physical hard drives that through either hardware or software are presented to the operating system as a single disk like any other.  When a file gets written to a RAID drive, the code that presents the collection of disks as one takes care of writing he file according to what mode it is in.   RAID is also used to prevent redundancy so that no hard drive is a single point of failure.  If a drive fails, the rest of the data can be recovered from the other drives to rebuild the missing data depending on the setting.

That wraps this QuickFire post up. Thanks for reading. Do you have an idea or suggestion for me to write about? Any feedback for it? Please Email suggestions@itlessonslearn.com or leave comments below.