Microsoft is making a big deal about a new kind of disk
drive that combines a regular disk with some amount
of flash memory in the same package. (See
for a presentation of this idea.
Except for speeding up booting and resuming,
I don't see why this is better than just adding
more system RAM memory, especially in OSs like
Windows and *nix where memory not needed for
processes is used as a disk cache.
The article mentions reducing the amount of time
a disk needs to spin, in order to reduce power conception,
but couldn't this be done just as easily by keeping data
in the OS cache? (I do recognize that flash memory
keeps its contents when the power goes off, but this
doesn't appear to me the major selling point of
hybrid disks in the articles I've seen).
The key issue I see is whether the OS or the disk controller
has a better conception of what to cache. Plus, what
happens, in worse case, if their conceptions conflict?
It's easy to imagine a case where the same data is
cached in both the OS cache and the on-disk cache.
Maybe a smart disk driver can prevent this from happening
but this whole approach seems anti-intuitive to poor me.
Where's the beef?