Author: genux

Linux – memory and where is it

To find out what memory you have onboard and also where it is, here is a neat command

lshw -class memory

Here is my output

  *-firmware                                 
       description: BIOS
       vendor: Acer
       physical id: 0
       version: V2.04 (01/15/07)
       size: 103KiB
       capabilities: isa pci pcmcia pnp apm upgrade shadowing escd cdboot acpi usb agp biosbootspecification
  *-cache:0
       description: L1 cache
       physical id: 5
       slot: L1 Cache
       size: 16KiB
       capacity: 16KiB
       capabilities: asynchronous internal write-back
  *-cache:1
       description: L2 cache
       physical id: 6
       slot: L2 Cache
       size: 4MiB
       capabilities: burst external write-back
  *-memory
       description: System Memory
       physical id: 12
       slot: System board or motherboard
       size: 2GiB
     *-bank:0
          description: SODIMM Synchronous
          physical id: 0
          slot: M1
          size: 1GiB
          width: 32 bits
     *-bank:1
          description: SODIMM Synchronous
          physical id: 1
          slot: M2
          size: 1GiB
          width: 32 bits

I basically have 2GiB of memory and also L1 cache (on die cache on the cpu) of 16KiB and 4MiB L2 Cache.

Here is a wiki page that details what L1 and L2 cache are CPU cache, basically L1 means on CPU die, and L2 means slightly further away from the L1 cache. If there is a memory call L1 is the first hit, then L2 and then the memory and then swap space (harddrive), the lower down the line means slower result time.

SugarCRM add a new menu item

SugarCRM is a very nice and open source CRM (Customer relationship management) system. Being open source means that you are more than welcome to add/alter your own modules to it. I am going to do some modules which add in some basic information and how-to’s. This how to is how to add to a left menu item and in this case a account main menu left menu item.

Also going to be doing a module for it, so that you can upload to different SugarCRM’s that you may have, e.g. development version and live version.

The module consists of the main manifest.php file which holds all of the main details, module name author, description etc and also the install definitions.

Here is a basic manifest.php file that has the main details and install definitions for adding a menu item to the Accounts module.

<?php
$manifest = array(
  'acceptable_sugar_flavors' => array(
          0 => 'CE',
          1 => 'PRO',
          2 => 'ENT',
          3 => 'DEV'
        ),
    'acceptable_sugar_versions' => array (
        'regex_matches' => array (
            0 => "5\.*\.*.*"
        ),
    ),
 
    'name'              => 'Accounts insert left menu addition',
    'description'       => 'This module inserts a left menu addition',
    'author'            => 'Ian Porter',
    'published_date'    => '2009/06/01',
    'version'           => '0.1',
    'type'              => 'module',
    'icon'              => '',
    'is_uninstallable'   => 1,
    'silent' => true,
);
 
$installdefs = array (
  'id' => 'AccountsLeftMenu',
    'vardefs'=> array( ),
  'custom_fields' =>  array (  ),
  'copy' =>
  array ( ),
'menu'=> array(
array('from'=> '<basepath>/Menu.php',
'to_module'=> 'Accounts', ),
),
       'beans'=> array (
                 ),
  'language' => 
  array (
  ),
);
?>

As you can see from the above code, the acceptable sugar flavors means any of the version types of sugar, development, pro etc.. and the acceptable sugar versions means which version of sugar e.g. version 4.1.2 or 5.etc. the name etc speaks for itself really.

The installdefs are what happens with the files and such when the module is installed, id is the name of the module, the one that we are focusing in on is menu, this will insert the code below into the a set menu module (this case the Accounts menu structure).

Here is the Menu.php file

<?php
if(!defined('sugarEntry') || !sugarEntry) die('Not A Valid Entry Point'); 
 
/* licence and you stuff */
 
global $mod_strings, $app_strings, $sugar_config, $current_user;
 
/* you need to create the DetailViewPersonal.php file to communicate with */
 
if(ACLController::checkAccess('Accounts', 'edit', true)) {
    $module_menu[]=Array("index.php?module=Accounts&action=DetailViewPersonal&return_module=Accounts&return_action=DetailView&record=".$current_user->id, "Personal View",  'Accounts');
}
?>

The ACLController will check the access level of the user for editable, ACL(Access Control Level), and if so place a new menu below called “Personal View”, the action in the module_menu array is what is called and thus you will need to have a DetialViewPersonal.php in the modules/Accounts directory, but this was just a how to, of how to insert a menu item and not the underlying code.

There is more to come!.

DeVeDe – convert video files to DVD’s

To convert video files into Video DVD’s for general usage well there is allot of applications out there that can do the job, command line (bash) if you want to or just use a GUI. I personally used to use a commmand line but now I am using a GUI because personally it just is as easy and sometimes it is nice to use a gui and not have to think as such.

The application that I use is called DeVeDe and it just makes the conversion very nice. Here is a step by step guide to use it.

Here is the output types that you can choose from, I have never used anything else but Video DVD.

Type of output

Start the create of the DVD structure, e.g. files and titles names.

The Title of the film

Properties of the title name(s) that you would like to come up on the main menu of the DVD.

Add the film

Add the files that you want to associated with the title on the main menu of the DVD, these could be of any type of file Xvid, MPEG, etc.

Pick the video

Titles and the files that are associated with the DVD structure.

Create the video

Create the DVD, this will progress to where to place the ISO image of the DVD structure.

The name of the files for temporary usage

Create the Full DVD Structure

Job done!

Finished!! all done.

Create DVD Properties Properties Title Properties Titles and file Create DVD Create DVD file names Create DVD files Finish

Virtual Box

After looking over the virtualization with different setups, KVM and VirtualBox I decided to use the virtualbox method because it just appeared to be nicer and with a nice GUI per machine just felt nice.

With the additions of the Guest Additions to allow for sharing of folders from the host machine to the virtual one and also the mouse was no longer taken within the virtual machine, I just liked it and to setup a bridge for the virtual machine to use for the networking I created a small script that does the job of deleting the KVM inserting modules into K/Ubuntu.

Here it is

#!/bin/sh
 
# to remove any kernel modules for kvm and then bring up the bridge for eth0
TMP=`lsmod | grep kvm`
RESULT=`echo $TMP | cut -d \  -f 1,4`
 
if [ -n "$RESULT" ]; then
 
        for i in 1 2
        do
                rmmod `echo $RESULT | cut -d \  -f $i`
        done
else
        echo "No kernel modules"
fi
 
# setup the eth0 for working with the bridge
ifconfig eth0 0.0.0.0
#ifconfig br0 down
 
#setup the bridge and bring it up
brctl addbr br0
brctl addif br0 eth0
 
ifconfig br0 up

Constant casting

Constant casting is when you are for example calling a external library function that does not understand the const (constant) type and so you will need to take it off because the program will do something funny otherwise, crash. etc..

Here is a example code of a const_cast

#include <iostream>
 
using namespace std;
 
int exampleextenalfuction(int value)
{
	// you can alter the value if you want to, since it is not longer a constant value
	return value  + value;
}
 
int main()
{
	const int constvalue = 2;
 
	cout << constvalue << endl;
 
	cout << "Calling a external function that does not use constant types" << endl;
 
	cout << exampleextenalfuction(const_cast<int&>(constvalue)) << endl;
}

Static casting

Static casting is when you want to convert one type into another, static casting is used allot of the time without even knowing. For example

int value = 2;
float t = float(value);

the float(value) is a static casting of converting one value into another. Below is a full code example

#include <iostream>
 
using namespace std;
int main()
{
	int i = 3;
	// the float(<value)> is basically a static cast from a interger value into a float
	cout << float(i) << endl;
	cout << static_cast<float>(i) << endl;
}

It is very small since static_cast’ing is very basic in nature, but the only problem is that you have to check to make sure that there is a error e.g not NULL.

Execution order

Execution order of programs code is very much a vital thing to understand and where some fault finds will take a long while to figure out. Basically like in maths where there is a order of calculating, well in coding structures and also multitasking and multi-threading setups the execution order may be incorrect for lines of code.

Here is some examples, the first is when will a function be called and the later when post/pre incrementation will take place.

#include <iostream>
 
using namespace std;
 
int value =1;
 
int setvalue2()
{
	cout << "setting value"<<endl;
	value = 2;
	return value;
}
 
int returnvalue()
{
	cout << "renting value"<< endl;
	return value;	
}
 
int main()
{
	// depending on the order of execution the value may be
	/* setvalue2 called first
		(setvalue2 = 2 / returnvalue = 2) = 1
	   returnvalue called first
		(setvalue2 = 2 / returnvalue = 1) = 2
	*/
	cout << setvalue2() / returnvalue() << endl;
 
	int i;
	i = i++ - ++i;	// not sure what i will be because the pre/post increaments 
	i = 3, i++, i++; // i will equal 5 because in correct order.
}