Arch Linux

paraflu

Member

Registered: 2008-02-23

Posts: 53

Optimizing application startup or why have the head of the need to mov

Some stupid questions

When i start konqueror or firefox, i often hear that my hd move its head.
Why it has to do this. Is there a way to place the needed files which firefox
or konqueror load at startup in a linear fashion so that the hd only reads linear?
Like some disk optimizing process and maybe placing the files at the outer end of
the hd to increase read speed.
Question is if the appllication really read the same files at every startup or not.
I know that this is mostly noexistend at flash storage but at harddsik level head movement
should be avoided or i am wrong here. It als has the possible benefit of decreasing startup time.
So has anybody more knowledge or thought about this before and had no success. That would be
interesting to know.
Thanks for your answers.

czar

Member

Registered: 2008-03-08

Posts: 115

Re: Optimizing application startup or why have the head of the need to mov

no matter what the head is going to have to move from where ever it was last to the firefox bin so is that what your hearing?

11010010110

Member

Registered: 2008-01-14

Posts: 284

Re: Optimizing application startup or why have the head of the need to mov

You theoretically can put stuff on the hd in optimal order (and for example Microsoft did it to speed up the boot of Windows XP)

I dont know the tool to do in in linux

Second reason why this happens - Most apps read the binaries from the root partition and configs from your home. Unless they are on the same partition the drive will have to travel like this

Caching may help here

paraflu

Member

Registered: 2008-02-23

Posts: 53

Re: Optimizing application startup or why have the head of the need to mov

@11010010110
Yes you are right, i did not thought about the configs and their location.
Yes i know about the ms tool and if i remember right there was also a 3rdparty application.

@czar
No not quite , my thoughts were more the following head movement not only the head
movement from `is` to `should`.

After thinking about the cache , i have some questions.
When i use my computer i have most of the time the same applications i would start.
So how can i load applications before, to get them into cache. Is there even a possibillity
to write directly to the cache. Another interesting thing about this is: What is the cache? Is it
protected memory (maybe kernel-memory) or is it user-memory. How does the cache know if
i start the apllication again , that it is the same file in the cache (md5 :-) ). What is the rule of the
cache ,how does it handle its memory if it is full, does it delete the first used application or does
it look for the running programs which are unlikely to start again (because they are running now).
What about the security? If a attacker could reach root and then use the cache to insert his code as a
regulary started apllication like cron, he could has a very nondetectable change od the system which
is gone after reboot. This thoughts gets me more interested in the cache.
So how can i get the application into cache. Gnome, bash and .xinitrc have the ability to start programs.
Maybe there is a parameter to load the applications stealth/quiet. But i really don`t want to have the
applications start i want them only in cache, maybe some application starts with big harddisk or cpu usage,
That would result in a less responsive system. I don`t like that. So i thought, what about loading the
application and then directly afterwards kill it. Now it should be in the cache or i am wrong here.
What do think about that and what can you tell me about the cache
Oh i got something other to ask does anybody know what is the reading speed difference of
the inner side of the hd plate and the outer side, with constant rotation speed?

Thanks for your answers.