Category Archives: Uncategorized

Ganglia Monitoring the ARI Cluster

Some screenshots of  the ARI cluster 11 nodes being monitored by ganglia.The node utilization of  load and network activity while running a parallel Monte Carlo simulation.



Leave a comment

Posted by on May 10, 2012 in Uncategorized


Tags: , , , ,


Nonprofit Worldreader gives Kindles to students in sub-Saharan Africa (and is working on a reading app for mobile phones). The organization just published the results of iREAD, its year-long pilot program in Ghana, and many of the findings are promising: Primary school students with access to e-readers showed significant improvement in reading skills and in time spent reading, and the program is cost-effective. The theft rate was “near-zero,” but nearly half the e-readers broke.

USAID funded the Worldreader Ghana study and independent firm ILC Africa did the research. iREAD “involved the wireless distribution of over 32,000 local and international digital books using Kindle e-readers to 350 students and teachers at six pilot schools in Ghana’s Eastern Region between November 2010 and September 2011.”

The full results are here (PDF). Some findings:

  • Kids learned to use e-readers quickly even though 43 percent of them had never used a computer before. Also…

View original post 638 more words

Leave a comment

Posted by on April 29, 2012 in Uncategorized


HPC (High Performance Compute) Cluster with MPI and ArchLinux

The following is a simple guide to setting up a cluster server and nodes using ArchLinux.The advantage of this approach is the flexibility of setting up a computer capable of high speed parallel computation using commodity hardware.
The procedure will be generally similar for most Unix based systems.The preference for Arch is driven by its philosophy of keeping-it-simple.’Simple’ is defined from a technical standpoint, not a usability standpoint. It is better to be technically elegant with a higher learning curve, than to be easy to use, and technically crap.Thus for a base system that will be as lean and fast as possible the minimalist base Arch install is perfect for the task at hand.

Open MPI

The Open MPI Project is an open source MPI-2 implementation that is developed and maintained by a consortium of academic, research, and industry partners. Open MPI is therefore able to combine the expertise, technologies, and resources from all across the High Performance Computing community in order to build the best MPI library available.

Machine setup

This guide assumes:

  • all the machines have been formatted and Arch base system installed according to the guide
  • the machines are connected via a TCP/IP network with the ip addresses and hostnames noted down as they will be required in later steps.
  • each machine has a common login account (in this case baloo)
  • all machines are using the same processor architecture i686 or x86_64

Its always a good idea to get the latest and up-to date Arch system so a quick:pacman -Syu

SSH setup

Open MPI communicates between the nodes and server over a secure connection provided by openssh secure shell.The full details of openssh options can be found from the arch wiki or the main openssh site .Here the bare minimum is given to get a cluster up and running.

Installing openssh

Accomplished by calling:pacman -S openssh
the default configuration for the sshd (server deamon) are enough for our needs.Inspect the /etc/ssh/sshd_config making sure all options are sane then continue.

Generating ssh-keys

To allow the cluster to send communication to the nodes from the server without the password being requested at every instance we shall use ssh-keys to enable the seamless logon.Using the defaults accept as given.No passphrase is selected , although inherently less secure than with one this precludes the need to setup key management via keyring.

Copying Keys to the server

Start the ssh deamon rc.d start sshd on both the server and the slave node and copy the public key from each node to the server.These will all end up in the home directory for our common user /home/baloo/.ssh/
The server publickey ( each of the publickeys copied over from the nodes are then appended to the authorized_keys file at ~.ssh/authorized_keys on the server.To enable two way communication its then possible to copy this file back to all the nodes after.
IMPORTANT:make sure the permissions for the following are all appropriate for reading and writing only by the owner:chmod 700 ~/
chmod 700 /.ssh
chmod 600 authorized_keys

logging into the remote machines via ssh should no longer require a passsword.

NFS setup

OpenMPI requires the programs that are to be run to be in a common location here .Instead of copying the program executable over and over to the slave nodes we set up a simple NFS shared directory with the actual folder on the server from which all the nodes will mirror the contents.

Server Configuration

Create the directory that will be shared /parallel in this instance and edit the /etc/exports to have the file mirrored to the remote nodes
/parallel . . . . . . . *(rw,sync)
and change the ownership permissions for the shared directory to nobody
chown -R nobody.nobody /parallel
edit /etc/conf.d/nfs-common.conf

Client Configuration

Edit /etc/fstab to include the following line so the clients can access the shared /parallel directory /parallel nfs defaults 0 0

Daemons Configuration

Setting the appropriate daemons to launch on start-up simply requires the modification of /etc/rc.conf and adding the appropriate entries.


DAEMONS=(…….sshd rpcbind  nfs-common nfs-server ……)


DAEMONS=(…….sshd rpcbind  nfs-common ……)

OpenMPI setup

With the preliminary setup out of the way we can now install the openMPI package , it comes with inbuilt wrappers for c++ fortran and c additionally the python wrappers can also be installed.It should be installed on both the server and nodes
pacman -S openmpi python-mpi4py python2-mpi4py
*the python wrappers are there if you want to implement the parallel programs in mpi for python

OpenMPI Configuration

To allow Open MPI to know on which machines to run your programs create a hostfile in the default user home directory.if /etc/hosts was set up you can use the host names here otherwise the IP addresses of the machines can work just as well.~/mhosts

#The master node is dual processor machine hence slots = 2
localhost slots=2
#The slave node is a quad core machine hence the slots=4
Or1oN slots=4

Running Programs on the cluster

To run myprogram on the cluster issue the following command from the /parallel directory:$mpirun -n 4 –hostfile ~/mhosts ./myprogram$mpirun -n 4 –hostfile ~/mhosts python

or$mpiexec -n 4 –hostfile ~/mhosts ./myprogram

$mpiexec -n 4 –hostfile ~/mhosts python

Leave a comment

Posted by on April 18, 2012 in code, Harware, Processors, Uncategorized


Tags: , , , ,

Curing Writers block

From the journal of applied behavioral sciences comes this gem.Not much can be said about it , really speaks for itself.

more at the jump

Leave a comment

Posted by on February 9, 2011 in Uncategorized


SBC(Single Board Computer) using 8086

The aim is to design and model an 8086 based computer and add several interfaced peripherals to it.The system has been designed to meet the following requirements :

Total 32Kx16 SRAM

Total 64Kx16 EPROM

I/O Ports Parallel

I/O Ports analog-digital

a block diagram of the system showing the functional units relationships to each other .The desccriptions that follow are based on this model and willthus be referrd to as per the module it currntly appears in And below is a preliminary sketch of the completed system.CAVEAT:This is how the completed system will look like however pin outs may change regarding the availiability of ICs.

I wıll be going through the different modules step-by-step in the upcoming posts .

ARES schematic

ARES Achematic of SBC

Leave a comment

Posted by on December 17, 2010 in Harware, Processors, Uncategorized


Hello world(or my god its full of quarks)!

The itch that must be scratched , ideas want to be free and until they see the light of day you’ll  never know if youve struck gold or that rancid sewer pipe that you were warned about.Long and short of it you never know until you try.My contribution to the sea of human thought on life the universe and everything.

-Allitertad Dystopia

Leave a comment

Posted by on June 21, 2010 in Uncategorized