Physical address vs. Virtual address

[mikeshn]

What is the difference between a physical address and a virtual address?

 

[AndyHui]

Have a look at what I wrote regarding swap files and virtual memory last time.

With virtual memory, you have up a 4GB address space available to an application. However, all of these addresses in the 4GB are virtual. The Virtual Memory Manager then maps these addresses to the RAM and/or swap file as a physical address.

 

[Nothinman]

I'll assume you mean in memory management.

The physical address is a number that refers to a specific page in memory that the hardware can address.

A virtual address is a number within the address space of your program (every process believes it has 2G or 3G of memory to work with on 32-bit arches, depending on how the OS splits the 4G available) that corresponds to a physical address. The physical address can be a real page in memory or it can be paged to disk and the VM has to read the page in and point the program to the new physical address.

 

[ScottMac]

OR, if you're talking about networking, the Physical address usually refers to the "MAC" address (sometimes called the "hard coded" or "hardware" address, and the virtual address refers to the Layer 3 address (like the IP or IPX address).

FWIW

Scott

 

[freebsddude]

Sometimes people also use this physical and virtual address terminology when talking about physical IP address(es) of a box/machine vs. a virtual IP address (like one that you would configure as a 2nd IP for virtual domains, etc).

OK, you have raised everyone's curiosity enough .... which context is the most pertinent ? (or did our interpretation(s) make you forget the question altogether )

 

[n0cmonkey]

virtual address could be the ip and the physical could be the location

(Sorry, silly screw up at work by a sales guy, luckily he didnt get GPS equipment...)