While waiting for Fedora 14, a question for the engineering types re: searching and finding
by Bill Case
Hi;
How does the cpu search and find stuff?
I am asking at the lowest abstraction level and hardware level. I have
read several operating system texts and have an overview understanding
of 'C'. There is a huge amount of searching and finding of text in
memory, conditional statements requiring comparisons, and the use of
entry points but not exact addresses from within both kernel space and
user space. It has occurred to me that a there is necessarily a lot of
physical or bit comparing going on. Too much, I would think, to keep
dumping a search criteria into a cpu register and then replacing the
contents of a second register from a block of memory until one matches.
I understand the use of hash tables. I am asking at a level lower than
that.
Is there a special unit within the cpu or memory were rapid comparison,
or partial comparisons are made during a search, before a criteria is
noted as found and moved into the cpu registers? In a generalized way,
at the hardware level, how are searched for criteria found?
I have googled for an answer and found nothing helpful. That usually
means I have somehow mis-posed the question, am working from wrong
assumptions or lack the correct terminology. Help chasing the
'searching' mechanism would be appreciated.
--
Regards Bill
Fedora 13, Gnome 2.30.2
Evo.2.20.2, Emacs 23.2.1
13 years, 6 months
Mplayer equalizer doesn't work
by Doug Wyatt
I'm setting up a 64-bit F13; mplayer is from rpmfusion. Box is
a core2 duo multiboot.
F12, 32-bit, is on another partition and mplayer works fine there.
The F13 mplayer is configured identically to the one in F12, but
in F13 the audio slides won't move; the video slides initially are
set at full scale and moving them produces no change. In F12 the
brightness and contrast are initially set at midscale - I usually
increase brightness by about 10 for dark videos.
Mplayer is set to use the Xv driver in both cases. In ~/.mplayer
config file, vo=xv, ao=alsa, vf=eq2.
Tried vf=hue=0.0:1.0,eq2=1.0:1.0:0.1:1.0:1.0:1.0:1.0:1.0, but
changes to the 3rd eq2 field (brightness) had no effect. Also,
pressing keys 3 or 4 have no effect.
Nouveau is installed on both F12 and F13. GPU is 9800GT.
Any ideas?
Regards,
Doug Wyatt
13 years, 6 months
problems with gigabit speeds on dual network card
by Genes MailLists
Anyone got any suggestions for this.
I have a linksys sr2024 Gb switch
Several things are plugged into this - all using cat 5e or cat 6 cables.
Some things are connecting with full Gb speed but the main firewall wont.
The machine has 3 intel nic's -
lspci | egrep -i ethernet
04:00.0 Ethernet controller: Intel Corporation 82573L Gigabit Ethernet
Controller (rev 01)
05:04.0 Ethernet controller: Intel Corporation 82541PI Gigabit Ethernet
Controller (rev 05)
05:05.0 Ethernet controller: Intel Corporation 82541PI Gigabit Ethernet
Controller (rev 05)
The 82573 is on board and not used - the other 2 nic's are used - one
for internal subnet and one for external.
The internet side is connected to a cisco 800 router (which I believe
is 10/100 only .. tho I cudnt swear for sure)
The inside is connected to the SR2024 Gb switch.
Both nic's come up in 100 Mb/s - I rebooted the switch, and I plugged
and unplugged the cables, I tried ethtool -r ethx a few times to no avail.
Other machines on same switch are happily running at full gigabit speeds.
Nothing in logs suggests a problem
Is there a problem with multi nics of same brand where they need to run
at diff speeds ? Or is this a quirk with some hardware somewhere ? Or ???
Appreciate any suggesions ... its getting tiring forcing renogiation!
thanks ...
gene/
13 years, 6 months
type 1400 avc denial messages
by Hiisi
Dear all!
I would like one of the computers on a LAN to send some files to another
computer on the same LAN using scp. Both computers can ping each other
without any problems and I set up ssh using keys authentication to work
without passwords. The task I'm talking about should be done in
automatic way so I wrote the following script (the part of it has been
erased for the purpose of simplicity):
...
OUTFILE=$(mktemp /tmp/out.XXXXXX)
chmod 666 $OUTFILE
...
scp $OUTFILE user@192.168.3.30:/home/user/
...
It doesn't work as expected. It creates the desired file in /tmp dir on
local machine but it doesn't copy it to remote machine. Instead I see a
lot of avc denial messages in dmesg output:
type=1400 audit(1288189100.508:9): avc: denied { name_connect } for
pid=9059 comm="ssh" dest=22 scontext=system_u:system_r:procmail_t:s0
tcontext=system_u:object_r:ssh_port_t:s0 tclass=tcp_socket
The script on the sender machine is invocated by procmail. I tested this
scp command manually and it can be done without any restriction. However
it doesn't work when it's in a script. How can I tell selinux (is it him
whom to blame?) to allow scp from a script?
TIA
P.S. Additional info:
# sestatus
SELinux status: enabled
SELinuxfs mount: /selinux
Current mode: permissive
Mode from config file: enforcing
Policy version: 24
Policy from config file: targeted
P.S.2 I don't want to disable SELinux completely because this system
is connected to the Interned and has static IP address. I see a lot of
interesting in root mail every day :-)
--
Love may laugh at locksmiths, but he has a profound respect for money bags.
-- Sidney Paternoster, "The Folly of the Wise"
13 years, 6 months
network failover; but not bonding
by sean darcy
I have a machine with 2 nic's. One nic (ETH0) is connected to a cable
modem. The other nic (ETH1) is connected to an internal lan. The
internal lan also has access to the internet.
The cable service, Time-Warner RoadRunner, is great when up, but is not
reliable. The connection through the internal lan (Verizon DSL) is
reliable but lousy. Sigh.
When the cable is down, the interface connection to the cable modem
stays up. An ifconfig shows ETH0 as up. The only way to tell is to ping
an outside address.
I thought of bonding. But that won't work since it will see ETH0 as up,
even if the cable service is down.
Is there a way to implement network failover that actually checks for
true internet connection?
sean
13 years, 6 months
wrong subject encoding in /var/mail/<user>
by Hiisi
Hi!
Looking at the /var/mail/<someuser> file I found that subject fields are
often in a wrong encoding while every other part of the message
displayed correctly. Example:
Subject: test =?koi8-r?Q?=D4=C5=D3=D4?=
Is there some settings in sendmail configuration ti prevent this
behavior? My system is:
2.6.32.21-168.fc12.i686
sendmail-8.14.4-3.fc12.i686
sendmail-cf-8.14.4-3.fc12.noarch
--
You will remember something that you should not have forgotten.
13 years, 6 months
Metamail
by Dave Close
This doesn't seem right. With Fedora 13:
$ yum info mailcap
Installed Packages
Name : mailcap
Arch : noarch
Version : 2.1.33
Release : 1.fc13
Size : 54 k
Repo : installed
>From repo : updates
Summary : Helper application and MIME type associations for file types
URL : http://git.fedoraproject.org/git/mailcap.git
License : Public Domain and MIT
Description : The mailcap file is used by the metamail program. Metamail reads
: the mailcap file to determine how it should display non-text or
: multimedia material. Basically, mailcap associates a particular
: type of file with a particular program that a mail agent or other
: program can call in order to handle the file. Mailcap should be
: installed to allow certain programs to be able to handle non-text
: files.
:
: Also included in this package is the mime.types file which
: contains a list of MIME types and their filename "extension"
: associations, used by several applications e.g. to determine MIME
: types for filenames.
$ yum --enablerepo=* list metamail
Error: No matching Packages to list
$ yum --enablerepo=* provides */metamail
No Matches found
Certainly, mailcap is used by programs other than metamail. But the
description seems to imply that metamail is the primary user. So, where
is metamail?
--
Dave Close, Compata, Irvine CA +1 714 434 7359
dave(a)compata.com dhclose(a)alumni.caltech.edu
"Email is the 'file system' for people that aren't geeks.
IMAP is NFS for your mom." --Tom Limoncelli
13 years, 6 months
Re: Intermittent freezing
by JB
Nigel Bishop <N.Bishop <at> ru.ac.za> writes:
> ...
Hi,
give us an output from an X terminal:
$ top
quit and include it in reply.
JB
13 years, 6 months
Icon for File Type
by Sawrub
Hello List,
I have a torrent file, which on double clicking correctly with
transmission, but the icon is that of a text file. Can some one point to
the way of changing the icon for all of the torrent files in my
directory with something visually appealing and meaningful.
I had been able to change the icon for a single file by going through
Properties and changing the icon, but the same does not work for all
files in one go. Also to mention the application associated is
transmission with all of the files as checked by `gnomevfs-info`.
Any help is welcome, Thanks
--
Saurabh Sharma
Linux user number: 490644
http://sawrub-blog.blogspot.com/
Open your doors.......It's time to look beyond Windows
13 years, 6 months
Sendmail Ldap routing
by Harley Race
I am using plain vanilla install of Fedora 13 and sendmail (sendmail-8.14.4-5.fc13.i686). In past versions of Fedora I was able to use sendmail to perform ldap-less routing using:
LDAPROUTE_DOMAIN(`mydomain.com')dnl
FEATURE(`ldap_routing',`hash -T<TMPF> /etc/mail/mailroutes',`null',`bounce')dnl
If I use the same settings in the sendmail.mc and try to build the sendmail.cf using the command:
./Build sendmail.cf
I get the following error:
*** WARNING: missing -T<TMPF> in second argument of FEATURE(`ldap_routing')
If I add -T<TMPF> to the second parameter like so
FEATURE(`ldap_routing',`hash -T<TMPF> /etc/mail/mailroutes',` -T<TMPF> `null'',`bounce')dnl
and build the sendmail.cf, I get the following error in maillog:
NOQUEUE: SYSERR(root): /etc/mail/sendmail.cf: line 173: readcf: config K line, map ldapmra: no map class
If I check sendmail.cf for ldapmra, where past version populated the field with null, this one will not.
What has changed in this version?
13 years, 6 months
