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reinob is offline reinob
2012-10-26 , 07:43
Posts: 1,808 | Thanked: 4,272 times | Joined on Feb 2011 @ Germany
#11
Originally Posted by pichlo View Post
Sorry in advance about the verbosity. I am typing this in a hurry. It might have found a more concise way of expressing myself if I had more time.
I found it just fine. Interesting observations!

Yes, that is the most common assumption. The whole American (and, since we monkey everything after the Americans, European too) production system is based on that. However, there was once a company that stopped assuming and started measuring. They found that, perhaps counter-intuitively, utilizing your production line close to full capacity is detrimental to its throughput. Any small variation at any link in the chain causes huge dropouts in productivity. Their findings were one of the bases for the Toyota Production System, or TPS as it has become commonly known.
When I was a child my father installed a game on our PC. It was made by some economist. You had a number of "production lines" (it was all a text-mode GUI) and you had to fiddle with some parameters, with the goal of maximizing production.

Without really understanding what the whole thing was about, I just played it like a game (most kids don't need instructions, they just find a way to, "evolutionarily", play better each time). After a few days I went to my father and said "that's weird, in order to get a better result, I have to stress a single line, where I would have thought that I need to distribute the load equally" (being a 10 year old, I used different wording, but the message was clear). His reply was that I was doing the right thing, and then showed me the book accompanying the software (no, we could not afford "cool" games) and there it was all explained.

Obviously *you* are right. Nothing is perfect, and the above only applies when no "slack" is needed, i.e. when everything happens deterministically and with no possibility of random delays or defects.

Still, in the particular case of the N900, or any computer for that matter, it seems counter-intuitive to "waste" resources (e.g. killing background programs to save memory, even if you will periodically need to start those programs again; moving stuff away from rootfs when you don't actually need that space for anything, etc.)
 
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pichlo is offline pichlo
2012-10-26 , 14:24
Posts: 6,445 | Thanked: 20,981 times | Joined on Sep 2012 @ UK
#12
Shortly after I wrote my long post, I thought, now hang on a minute, how about burning a CD, for example? Filling it to only 75% is wasteful, is it not? Then I realized what the answer was. Yes, it was wasteful, but... a burnt CD is not a dynamic system! Once burnt, the content is static. So you do not need any slack.

So I guess the real answer depends on your usage pattern. If you do not experience any problems as it is, consider your N900 more-or-less set up and do not expect any changes in a foreseeable future, then it really does not make much sense to free up any rootfs space at all. Do not try to fix what ain't broken.

FWIW, here is my real life example: I bought my N900 second-hand. It had 67 MB rootfs free. I upgraded to CSSU and suddenly I only had 40 MB. I did not like the change but thought, what the heck, I'm not gonna need much space anyway. Until I decided to upgrade again, to CSSU-T and the damn thing complained that I needed at least 48 MB. I resolved it by running the upgrade from xterm instead of HAM but decided to set 40 MB as my limit. Come to think of it, it is only 17.6%, a bit short of 25% I preached before
 

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bozoid is offline bozoid
2012-10-26 , 19:37
Posts: 95 | Thanked: 66 times | Joined on Mar 2012
#13
i started hitting problems with my n900 had less than 5MB in rootfs.
apps wld often crash when below that.
i stuck with that for about a few months & noticed that remaining space would always fluctuate by abt a few megs.
hope the info helps.

anyway, i've modified my n900 since then.
directories /usr/bin, /usr/share, /usr/lib, /lib, are all mounted from corresponding directories i created in emmc during /sbin/preinit.
lots more storage for me now...

kh
 
bozoid is offline bozoid
2012-10-26 , 19:39
Posts: 95 | Thanked: 66 times | Joined on Mar 2012
#14
oh jst a note...
it would be most strategic to keep things that often run in NAND/rootfs.
those that are huge & not often invoked, keep them in emmc.
note: it's a lot of work...

kh
 

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pichlo is offline pichlo
2012-10-26 , 20:20
Posts: 6,445 | Thanked: 20,981 times | Joined on Sep 2012 @ UK
#15
Originally Posted by bozoid View Post
oh jst a note...
it would be most strategic to keep things that often run in NAND/rootfs.
those that are huge & not often invoked, keep them in emmc.
Amen. One would hope that developers keep that in mind, but experience shows that this is not always the case.

note: it's a lot of work...
That might be why...

BTW 5 MB? I never dropped that low. The lowest I got was 29 MB - and heard alarm bells ringing
 
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peterleinchen is offline peterleinchen
2012-10-26 , 20:26
Posts: 4,118 | Thanked: 8,901 times | Joined on Aug 2010 @ Ruhrgebiet, Germany
#16
Have atm only 15MB left (and yes my alarm bells are on), but still everything is smooth. Just an update to system software from Nokia (err. CSSU ) would not run anymore...

But have lots of kernels, modules, maps backups and so on on rootfs, so there is enough MB to move fast and easily, if necessary

--edit
one noticed flaw:
when downloading simultaneously from different browser windows, one of the downloads may stop/fail
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Last edited by peterleinchen; 2012-10-26 at 20:30.
 
reinob is offline reinob
2012-10-27 , 19:08
Posts: 1,808 | Thanked: 4,272 times | Joined on Feb 2011 @ Germany
#17
Originally Posted by bozoid View Post
anyway, i've modified my n900 since then.
directories /usr/bin, /usr/share, /usr/lib, /lib, are all mounted from corresponding directories i created in emmc during /sbin/preinit.
lots more storage for me now...

kh
Care to explain what exactly you've done? Would be nice if you could post your /sbin/preinit!
 

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bozoid is offline bozoid
2012-10-28 , 14:40
Posts: 95 | Thanked: 66 times | Joined on Mar 2012
#18
Originally Posted by reinob View Post
Care to explain what exactly you've done? Would be nice if you could post your /sbin/preinit!
Basic idea: /lib, /usr/bin, /usr/lib, /usr/share are all from eMMC. ie: I do a "mount -o bind /home/mnt/.emmcfs0/lib /lib" etc in /sbin/preinit. There's a /lib-nand that still resides in NAND, & which was the original /lib. Same for usr/bin, /usr/lib, /usr/share. Files in /lib-nand are soft linked over to /lib (on eMMC). Due to the way it is, install of new apps would install into eMMC.

My /sbin/preinit attached. Not the latest yet as there's one small bit I'm fixing.

There's actually some more details... will post later if you want.

I did all that on a new flash image, & then reinstalled my apps.
Found out FAM lets one export list of installed apps & can reinstall all of them using that same list! But I decided to scrutinize each deb being installed this time to control mem usage (separate story; but basically, with only BT & GSM turned on, after 20 hours of idle time, I still have 80% batt left).

kh
Attached Files
File Type: zip preinit-20120903.zip (4.1 KB, 75 views)
 

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tonypower88 is offline tonypower88
2012-10-28 , 15:25
Posts: 96 | Thanked: 29 times | Joined on Jun 2011
#19
Originally Posted by bozoid View Post
Basic idea: /lib, /usr/bin, /usr/lib, /usr/share are all from eMMC. ie: I do a "mount -o bind /home/mnt/.emmcfs0/lib /lib" etc in /sbin/preinit. There's a /lib-nand that still resides in NAND, & which was the original /lib. Same for usr/bin, /usr/lib, /usr/share. Files in /lib-nand are soft linked over to /lib (on eMMC). Due to the way it is, install of new apps would install into eMMC.

My /sbin/preinit attached. Not the latest yet as there's one small bit I'm fixing.

There's actually some more details... will post later if you want.

I did all that on a new flash image, & then reinstalled my apps.
Found out FAM lets one export list of installed apps & can reinstall all of them using that same list! But I decided to scrutinize each deb being installed this time to control mem usage (separate story; but basically, with only BT & GSM turned on, after 20 hours of idle time, I still have 80% batt left).

kh
how do I use the it ?

do I just execute it or use it as startup script?
 
reinob is offline reinob
2012-10-28 , 17:05
Posts: 1,808 | Thanked: 4,272 times | Joined on Feb 2011 @ Germany
#20
Originally Posted by tonypower88 View Post
how do I use the it ?

do I just execute it or use it as startup script?
Don't even think about using the posted /sbin/preinit if you are asking this question. Not meaning to sound arrogant or anything, but this is not a plug-in replacement for anything.

I wanted him to post his preinit to *read* it, not to *install* it. You can do the same and take it from there.
 

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