Virtual Memory allows you
to pretend you have more memory (RAM) than actually
exists on your machine. In the old days, all of an
application would be loaded into memory so you
couldn't have more apps in memory than your RAM
could take, so for instance using that model a
Windows machine with 64MB of RAM could probably
only have MSIE and Word open before using up all of
system memory. With virtual memory, you pretend you
have a whole bunch of memory by only loading parts
of each app at a time yet the app thinks that it's
all in memory at once. That way I can have Word,
IE, Excel, Powerpoint and Emacs open at the same
time without using up all of my system memory. The
way this is done is via a process called paging
where parts of the program are retrieved from disk
when needed and older uneeded parts are unloaded
and written back to disk if modified.
The post I linked to is claiming that we should go
back to a model where all of an app is loaded into
memory. This would eliminate the constant reading
and writing to disk involved in paging but now
people would have to run fewer apps with the same
amount of memory and program startup would balloon
since all of a program would have to be loaded into
memory first before running, plus unloading an app
would also involve much longer writes to
disk.
Anyway, speaking of operating system stuff, the
Linux kernel sucks. Not for any reasons of
performance or quality mind you but because of
the problems highlighted in this post. No one
thinks of commenting anything and instead just
throws in their hacky code with comments
like/* You aren't
supposed to understand this */
The projects in my operating systems class have
all been fairly trivial to implement BUT have taken
days to do because we've wasted so much time trying
to figure out what anything does simply because no
one bothers to comment anything. Whenever comments
do occur they are completely arbitrary (one
commented function in a file with 10 or 15) and
contain miniscule amounts of information.
*sigh*
By the way, Yes I know that this isn't much better
in commercial products (and in fact is typically
quite worse) but that doesn't make it right.
By the way,
Steve Gibson is a fraud.