9.10.2009 von pit.

Jonathan Corbet presented a informative presentation about the recent linux kernel work. It was held at the 11′th realtime Linux workshop, and offers some insides and statements not always presented in the normal press, like from 2.6.27 -> 2.6.31++ rough timeframe (October 9, 2008 to September 18, 2009) 48,000 changesets was merged by 2,500 developers and 400 employers. This result is that the kernel grew by 2.5 million lines, or better 140 changesets merged per day and 7267 lines of code added every day. But he also depicts some major functionality added by each version and why it’s needed. paired with some funny pictures a nice walk through. The other papers from the conference are also a good read, take a look at them by yourself

Geschrieben in storage, net, programming, unix, performance | Keine Kommentare »

9.10.2009 von pit.

TUD presented EASY-A and achieved a record in transmission. They claim its very energy efficient in that the emitter and receiver only need one bit resolution for transmission. The signals use 4GHz bandwith and it took 6.4 seconds for 8 Gigabyte.
one have to admit, that they (still) used cable for transmission, but they’ve designed/created the demonstrator using the concept of their 60 GHz wireless transmission. They estimate about 5 years before this could be used in commercial products.

Geschrieben in net, science, performance | 1 Kommentar »

22.9.2008 von pit.

Cisco announced that they will aquire jabber Inc. Jabber which was the protocol name before it was adopted by the IETF as XMPP (extensible Messaging and Presence Protocol), is an open XML technology for real-time communication. Due to it’s open nature you find different (and many OSS) implementations for various clients and servers. I follow from time to time the progress of ejabberd, but it really depends what you have already in your environment established, so it worthwhile to take a look at metajacks article and the answers. the statement about being a memory hog seems to be much better with the recent versions. a worthwhile read about mcroblogging integration is again by Jack Moffit

Geschrieben in mobile, net, programming, web | 1 Kommentar »

18.8.2008 von pit.

impressive numbers demonstrated by Tervela, especially if you look at the latency achieved. Wonder which companies have them on the watchlist.

Geschrieben in net, performance | 1 Kommentar »

1.8.2008 von pit.

Australia’s Center for Ultrahigh-bandwidth Devices for Optical Systems explain in a research paper how they want to achive 640 Gb/s with all optical signal processing

Maybe this comes as a rescue to united states speed trap

Geschrieben in net, science, performance | 1 Kommentar »

30.7.2008 von pit.

The entry page to the conference proceedings. If you’re interested in net measurement areas, it’s wortwhlie to have a look. Thorsten just send me the link to ufsdump. good papers, even I have some things to add about this. But unfortnunatly I have to postpone this. as a remark for my self, anonymous mem, dstat.

Geschrieben in net, performance | 1 Kommentar »

22.7.2008 von pit.

announced that all online conference proceedings are now freely available to everyone. Awesome! take a look at the proceedings

Brocade to buy foundry

and an impressive demo about what’s possible with javascript

Geschrieben in net, web, unix | 1 Kommentar »

17.5.2008 von pit.

Take a look at the a presentation by Bob Metcalfe where ethernet its heading to from his perspective, the convergence between SONET and ethernet, the role of embedded devices and more about alien wavelength, missing mid span compatability. presented with a nice sense of humour

Geschrieben in net, performance | Keine Kommentare »

16.5.2008 von pit.

cedmagazine has a nice one sheet overview of the different Fiber Topologies in use in the US.

Geschrieben in net | Keine Kommentare »

16.7.2007 von pit.

even the echo service is disabled on Linux machines, it’s nevertheless an easy way to figure out spurios network delays. TIn perl the basics are already written in the NET::PING module. I only added some timing to it. If you don’t have the perl modules installed, a workaround is creating a script containing the line

echo $2 | /usr/bin/netcat -v $1 7

which you could than invoke with time scriptname host.domain.dmn string_to_use
here ist the other way

#!/usr/bin/perl
# simple tcp echo programm
# sample usage (verbose mode)
# /xxx/bin/tcp_echo.pl -v 1 -h host.domain.dmn
# /xxx/bin/tcp_echo.pl: host.domain.dmn 2
# res = 1 host host.domain.dmn time: 0.012088
# sample usage (normal mode)
# /root/bin/tcp_echo.pl -h host.domain.dmn
# res = 1 host host.domain.dmn time: 0.010903
#
use strict;
use Getopt::Long;
use Net::Ping;
use Time::HiRes;
use Time::HiRes qw(gettimeofday tv_interval);

my $program_name = $0;
my $timeout = 2;
my $hostname = “localhost”;
my $debug = 0;

sub helpMessage()
{
print “$program_name [-h|-?] [-v #] [-t #] [-h FQDM] [\n”;
print “-help|? this message\n”;
print “-v[erbose] enables debug messages \n”;
print “-t[imeout] timeout (default: 2)\n”;
print “-h[ost] hostname FQDN (default: localhost) \n”;
exit 1;
}

sub run()
{
my $t0 = [gettimeofday];
my $res = pingecho( $hostname, $timeout );
my $t1 = [gettimeofday];
my $elapsed = tv_interval $t0, $t1;
print “res = $res host $hostname time: $elapsed\n”;
}

Getopt::Long::Configure (”bundling”);
my $l_result = GetOptions (
‘help|?’ => sub { helpMessage() },
‘verbose|v=n’ => \$debug,,
‘host|h=s’ => \$hostname,
‘timeout|t=n’ => \$timeout);

print “$program_name: $hostname $timeout \n” if $debug;

&run();

Geschrieben in net, programming | Keine Kommentare »