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46  General Category / General Discussion / Re: Ways to save ram usage on: January 01, 2010, 05:35:03 PM
Most of that is cached and shared anyway.

And a lot of it has to do with what libraries your applications are compiled for. Glibc is a massive, bloated hog.  Most people could use the trimmed down uclibc.  Everything you see there could get away with using 64MB very well and have plenty left over.

Also, protected mode memory allows more memory than exists to be mapped.  Applications need to tell the kernel how much memory they need before its used, otherwise currently used areas could be clobbered.  Its easy to ask for more than you need now  than to go over budget later.
47  General Category / General Discussion / Re: pdflush and syslogd 100% CPU usage on: January 01, 2010, 05:20:50 PM
From my experience, the slow storage device might have been mounted synchronously, or some log files might have the sync file attribute set.  That means the writes are immediate.  Good for log files when debugging crashes, because the last events before impending doom are saved.  Bad for slow sdcards!

You can tune the kernel to flush every minute, hour, day, or never. Check to see how often:

cat /proc/sys/vm/dirty_writeback_centisecs

and if its 500, you can increase it to 50000 by "cat 50000 > /proc/sys/vm/dirty_writeback_centisecs"

and give your storage systems a rest.  But if the power ever goes out without a "sync" command, massive data is lost.

You can also check the mounted file systems for the any sync options by checking /etc/mtab:

cat /etc/mtab

You can check the rarely used, but sneaky file attributes with lsattr and set them from chattr...

from "man chattr"
"When  a  file with the `S' attribute set is modified, the changes are written synchronously on the disk; this is equivalent to the `sync' mount option applied to a subset of the files.

All kinds of ways to tune the system and make it fast or force data updates.
48  General Category / General Discussion / Re: Setting Up Mail Server on: January 01, 2010, 03:40:32 PM
Mail servers have traditionally run on all kinds of processors without changes between config files.  I'm running Sendmail on mine.
49  General Category / General Discussion / Re: pdflush and syslogd 100% CPU usage on: January 01, 2010, 03:35:09 PM
Any chance they are writing to a slow sd card?
50  Linux Stuff / Linux distributions / Re: Do you still need to install the SheevaPlug Installer if you just bought a Plug? on: January 01, 2010, 07:25:17 AM
Plug in, log in!
51  Hardware and U-Boot firmware / Hardware / Re: Intel to build 30w "Microserver" on: October 30, 2009, 04:03:01 PM
30 watts a "low power microserver?"  I'd hate to see their high powered servers.
52  Linux Stuff / Kernel / Re: Weird Kernel modprobe issues on: October 20, 2009, 08:19:01 PM
Looks like a few people have...

http://www.google.com/search?q=zd1211rw+kernel+oops
53  General Category / General Discussion / Re: Sun Virtual Box? on: October 18, 2009, 07:25:36 PM
If you don't mind emulating a x86 machine with Bochs, in theory it can be done.
54  Hardware and U-Boot firmware / Hardware / Re: Corrupted filesystem just after mkfs? on: October 15, 2009, 09:01:15 PM
mkfs.ext3

Simple, yet effective alternative command compared to forcing mkfs.ext2 to create a journal.
55  Hardware and U-Boot firmware / Hardware / Re: Can't get USB Audio to work on: October 11, 2009, 08:47:19 PM
Have you used the alsamixer utility to adjust the output?
56  General Category / General Discussion / Re: Sheevaplug installer - version 1.0 on: September 12, 2009, 03:16:11 PM
Any issues with having the host PC be 64-bit Linux?

If your PC can talk USB and has the ftdi libs with ftdi_sio kernel module installed, it will work.
57  Hardware and U-Boot firmware / Hardware / Re: SheevaPlug v2 - Hardware Requests on: August 24, 2009, 12:18:02 PM
What is heating?

My guess is a device to be used in extreme environments.  I work in refrigeration and see most of the failures due to cold and condensation.  Its a whole different world at -20F.
58  Hardware and U-Boot firmware / U-Boot stuff / Re: U-Boot not responding to keyboard input on: August 24, 2009, 06:54:28 AM
Hit any key to stop autoboot: 0

does it to me too!  Can't stop u-boot.  Tried minicom and cu.

Reflashing with alpha-6 works, but this problem keeps coming up and requires a new reflash every time...
59  Hardware and U-Boot firmware / U-Boot stuff / Re: Where does u-boot store the env variables such as bootargs? on: August 19, 2009, 03:26:23 PM
# fw_printenv
# fw_setenv
60  Linux Stuff / General Linux questions / Re: cron for regular user ? on: August 18, 2009, 09:34:25 AM
You might have to set yourself in the crontab group.

usermod -g crontab you
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