speeding up disk-based laptop by moving /usr to flash?

[tmetro-blu-5a1Jt6qxUNc at public.gmane.org (Tom Metro)]

Brendan Kidwell wrote:
> My goals are to maximize the perceived performance of my Thinkpad as
> well as maximizing battery life.
> 
> 2. Keep the 60GB parallel ATA (IDE) hard drive and keep most of my stuff on
> it.
> 3. Install a 16GB "133x" (20MB - 25MB per second) CF card in a PCMCIA-CF
> adapter in my PCMCIA slot. -- I never use the slot for anything else.

I'd look around and see if you can find a software layer that will use 
the CF card as a dynamic cache for the hard drive. Some file systems 
(ZFS) will use SSDs in this fashion. There may be something more general 
that would let you couple the CF and the HD as a single block device.

With the CF being persistent storage, after a while it should mostly 
contain the 16 GB of your HD that you use most often, and let your HD 
stay spun down.


> I'm guessing this will improve my boot time...

The December "Linux Journal" on embedded systems had an article on 
improving boot times, though the majority of the suggestions are 
probably too low-layer to be practical here.


> - Will keeping a CF card in a PCMCIA adapter online consume a lot of
> additional power?

I wouldn't expect so. If you succeed in increasing the spin down time 
for the HD, it should be a win.


> Would I get different performance from using an SD card in the SD slot? From
> what I read tonight it seems the "Secure Digital" interface has even more
> limited bandwidth than a typical CF card.

Memory card readers are often internally interfaced via USB, so it seems 
logical that the CF card could outperform it, but why not test it, if 
you can.

  -Tom

-- 
Tom Metro
Venture Logic, Newton, MA, USA
"Enterprise solutions through open source."
Professional Profile: http://tmetro.venturelogic.com/