Sharing a CD/DVD drive over the network with OS X

Problem

I’ve got a Mac Mini with a broken DVD drive, but I wanted to install iWork on it from the installation DVD.

Solution

I used the Remote Disc feature of Leopard that Apple developed for the diskless MacBook Air to share another machine’s drive over the network.

Instructions

On the client machine were you would like to use the CD / DVD, you need run 2 commands on the terminal.

defaults write com.apple.NetworkBrowser EnableODiskBrowsing -bool true
defaults write com.apple.NetworkBrowser ODSSupported -bool true

Then restart your computer.

Next on the server machine where you will be inserting the physical disk, you must enable CD / DVD sharing in System Preferences > Sharing.

CD & DVD Sharing with Remote Disc

Once you’ve done that, insert your CD or DVD and then you should be able to connect to it via finder on the client machine.

Cloud Hosting Providers

Over the past year or so there has been a massive surge in the amount of companies offering Cloud Hosting services. In this post I’m going to outline the key players.

Go Grid
Amazon Web Services (EC2, S3, and CloudFront)
Google App Engine
Mosso
Slice Host
Media Temple
Flexiscale
Joyent

There are also some Cloud Management Platform providers, who generally offer tools to help you work with other Cloud Hosting services, these include:

And there are even some open source projects to help you build your own cloud:

Eucalyptus – Elastic Utility Computing Architecture for Linking Your Programs To Useful Systems – is an open-source software project for implementing “cloud computing” on clusters. Essentially a vendor neutral, EC2 compatible cloud platform.
Nimbus – An open source toolkit that allows you to turn your cluster into an Infrastructure-as-a-Service (IaaS) cloud.

Go Grid

Go Grid allows you to deploy and manage your own virtual servers from their control panel. The servers can be of 4 main types: Load Balancer, Web / App Server, Database Server and, Cloud Storage.

The site doesn’t give a lot of detail about what happens once you’ve created your servers, apart from to say they are Real servers with Full Access. Presumably you would then need to configure the software (Apache, IIS etc..) on each server individually.

Billing Model

GoGrid charges based on Server Ram Hours and outbound data transfer. CPUs and Storage are fixed relative to the RAM chosen for each vserver.

CPU’s are guaranteed at a minimum ratio of 1 Xeon Core per 4 GB of Ram, therefore if you create a server with 1GB of RAM, it will have 1/4 of Xeon Core reserved for it’s use.

Server RAM	Core Guaranteed (P4 2.0 GHz equivalent)	Core Burst
512 MB	1/8	1
1 GB	1/4	1
2 GB	1/2	1
4 GB	3	3
8 GB*	6	6

Storage is also determined by the amount of RAM chosen for each vserver, however additional storage can be made available through the Cloud Storage system.

Server RAM	Storage
512 MB	30 GB
1 GB	60 GB
2 GB	120 GB
4 GB	240 GB
8 GB	480 GB

1 x 1GB RAM x 24 hours x 30 days = 720 Server RAM/hours.

Prices start from $0.19 per Server Ram hour, therefore a 1 GB / 0.25 Xeon Core machine would cost $136.80 per month. However this would drop as low as $57.60 on their Enterprise plan, with a minimum commitment of $2499.99 a month. Bandwidth charges would be on top of this, and they start from $0.50 per Gigabyte dropping to $0.17 per Gigabyte if you commit to 6 TBs a month ($999.99).

Summary

Go Grid is currently very much a “build your own cloud” solution. The system will not scale automatically to adjust to spikes in demand, you would need to anticipate them and create spare capacity in advance.

Amazon Web Services

Amazon Web Services consists of 3 main products:

Elastic Compute Cloud (EC2) – A xen-based virtual server hosting platform. You can upload machine images to their platform, and then run them as virtual servers.
Simple Storage Service (S3) – A cloud storage solution. Let’s you store files safely and reliably in the cloud.
CloudFront – A content delivery network enhancement to S3 that copies your files to a global network of edge servers. Requests for files are automatically routed to the nearest edge location, so content is delivered with the best possible performance.

Billing Model

CPU power is measured in EC2 Compute Units. One EC2 Compute Unit provides the equivalent CPU capacity of a 1.0-1.2 GHz 2007 Opteron or 2007 Xeon processor. There are 5 main instance types, each providing a different level of processing power, storage and memory.

Prices for EC2 Unix / Linux instances hosted in the United States are as follows:

Standard Instances	Price	CPU	Memory (GB)	Storage (GB)
Small (Default)	$0.10 per hour	1	1.7	160
Large	$0.40 per hour	4	7.5	850
Extra Large	$0.80 per hour	8	15	1690
High CPU Instances
Medium	$0.20 per hour	5	1.7	350
Extra Large	$0.80 per hour	20	7	1690

A small instance running continuously would therefore cost approximately 0.10 x 24 x 30 = $72 per month.

Bandwidth is charged on top of this at the following rates:

Data Transfer In
All Data Transfer	$0.10 per GB

Data Transfer Out
First 10 TB per Month	$0.17 per GB
Next 40 TB per Month	$0.13 per GB
Next 100TB per Month	$0.11 per GB
Over 150 TB per Month	$0.10 per GB

Summary

Amazon web services is a very competitively priced platform that offers a great deal of flexibility, however it also requires a fair amount of technical expertise to get up and running and it doesn’t come with any load balancing system, so you would have to build your own.

To address these problems, some third party companies have emerged who offer control panel and management systems for AWS. Examples of such companies include RightScale and 3tera. Their products are sometimes referred to as Virtual Private Data Centres, or Cloud Management Platforms.

Rightscale offer Website Edition package, which comes with all the tools and images you need to deploy a load balanced web / database cluster on AWS. For $500 a month, it will let you manage up to around 20 servers.

Installing Zend Framework on OS X (Leopard)

Today I needed to use Zend Framework on my iMac’s local web server, so here’s how I installed it.

I prefer using subversion where possible to download any open source projects, and since Zend have an svn repository available I decided to use that.

sudo svn co http://framework.zend.com/svn/framework/standard/branches/release-1.7/library/ /usr/lib/php/libraries/zend-framework-1.7/

This will follow the latest updates to version 1.7 – you can simply run svn update anytime a minor version is released.

You can then include this in any of your projects with:

set_include_path(
get_include_path().PATH_SEPARATOR.
'/usr/lib/php/libraries/zend-framework-1.7/');

Although I’ve gone through these steps on my OS X Leopard workstation, they would also work equally well on other Unix / Linux distributions like Ubuntu, Centos, Fedora etc..

Mollom beats Akismet at blocking spam

I’ve been using the WordPress Mollom plugin for about 6 months now, and I have say that I’m very impressed. In that time, I can count on one hand the number of spams that have slipped through the net. When I was using Akismet, spam comments were getting through daily.

Here are the stats that Mollom produced for my blog:

mollom-statistics

Which anti-spam plug-ins do you use on your blog? and how successful are they? Let us know by posting a comment!

Granting site administrator permissions with WPMU

It took us a while to work out how you grant additional users the Site Administrator permission in WordPress MU. We were expecting this to be in the users page, but actually it’s hidden on the Site Admin > Options page.

WPMU Site Administrator Permissions

However, once you realise where the option is, it’s actually incredibly simple. You simply specify all the administrator usernames in a space separated list, and press save.

On the edit user page you should then see that the users have Additional Capabilities: Administrator displayed.

Fixing a blank screen with the WordPress Mollom Plugin

If you get a white screen after the Mollom Captcha step when trying to add a comment to your blog, then check your PHP errors logs. I was experiencing this problem, and looking into the logs showed the following:

[09-Feb-2009 11:11:53] PHP Fatal error:  Call to undefined function mb_convert_encoding() in /sites/pyrosoft.co.uk/http/blog/wp-content/plugins/wp-mollom/wp-mollom.php on line 1371

The mb_convert_encoding() function is part of the PHP mb_string module, so fixing this was relatively easy. As my server was running Centos 5, I could just use yum to install the mb_string functions:

yum install php-mbstring

And then finally, I restarted Apache:

apachectl graceful

NVIDIA ION Actual Size

NVIDA have released a computing platform that fits in the palm of your hand, and is capable of playing 1080p HD movies, with 7.1 digital surround sound. The NVDIA ION boards will power Netbooks, Small Form Factor PCs, and we will no doubt see some of them integrated directly in to TV sets.

NVIDA ION Actual Size

Specifications

Intel Atom CPU & NVIDIA GeForce 9400M GPU
Size: 100 mm x 72 mm (Pico-ITX)
Power Consumption: 18W
Max resolution: 2560 x 1600
Network: 10 / 100 / 1000 Mbps
Video Out: HDMI / DVI / VGA

I recently retired my home media server as it was using too much power (approx 200 Watts!), so with a typical consumption of less than 20 watts, the new ION platform would make a perfect replacement.

It is rumored that the NVIDIA ION may power a refreshed version of Apple’s Mac Mini, potentially as soon as March 2009, and with Apple’s Snow Leopard OS designed to take advantage of the power of GPU cores for ordinary desktop operations – we may soon see these start to replace large inefficient workstations.

It happened to the laptop market with netbooks, now it’s time for desktops with nettops.

Install WordPress and WP plugins with Subversion

In my opinion, the best way to install WordPress (WP) is by using subversion (svn). This can also be used to install WP plug-ins. Subversion makes it incredibly easy to upgrade / update when future versions of the software is released. You simply run either svn update or svn switch.

The following instructions assume you have shell access and subversion installed on your system.

WordPress

Installing WordPress with Subversion

Run the following command to check out the WordPress code to your blog directory:

svn co http://svn.automattic.com/wordpress/branches/2.7/ /path/to/blog/

Follow the 5 minute installation instructions, ignoring steps 1 & 5.

Updating WordPress to the latest minor release with Subversion

Navigate to your wordpress installation directory and run:

svn update

Upgrading WordPress to a new major release with Subversion

Navigate to your word press installation directory and run:

svn sw http://svn.automattic.com/wordpress/branches/2.8/

Replacing the repository url with the version you wish to upgrade to.

Plugins

Installing a plugin with svn:externals

If you install WordPress using subversion, it should already be set up with akismet as an svn:external plugin. If you want to install any other plugin this way, just follow these steps:

cd wp-content/plugins

svn propedit svn:externals .

If this command complains about not having an editor set you may need to run something like

export SVN_EDITOR=vim

before trying again. Otherwise, you should now be in your favourite text editor with the svn:externals file open for editing. Add an additional line for the plugin you wish to install. In this example, I’m going to use the Mollom comment spam protection system. The line should look like:

wp-mollom http://svn.wp-plugins.org/wp-mollom/trunk/

Save and exit the text editor, then run:

svn update

This should check out all the plugin files. You can then configure the plugin in the WordPress admin panel.

Updating a plugin with svn

The beauty of using subversion to install your plugins is that it’s a breeze to update them. From your the top level WordPress directory, just run:

svn update

This will update all of your plugins along with your main WordPress installation. If you want to update the plugins on their own, then just run that command from inside the plugins folder.

Fubra Investment Roundup Feb 09

Since the summer of 2008, we’ve invested in a number of start-up companies. We’ve been looking for businesses that compliment our own, and specifically where we could leverage our existing assets and benefit from the economies of scale. As I’ve mentioned before, we look for people with a unique idea, who are prepared to work hard and who can build the product/service themselves. All of the following companies met that criteria:

Clear Books Limited

Clear Books is an online accounting software service run by Tim Fouracre. He’s a chartered accountant, entrepreneur and programmer and has been working on the system for 6 months now. We’ve been beta testing it for our Fubra Accounts, and we’re really happy with its progress. The intelligent bank statement import feature has already helped us cut down the amount of time we spend book keeping from 10 days a month, to 2 days a month! We’ve also used it to complete our quarterly VAT returns, and our 6 monthly FSA regulatory reporting.

Screenshot of Clear Books home page.

UMPC Media Limited

UMPC Media is a joint venture between Fubra, Matthew Dunham and Steve Whiteley. The company aims to develop a number of web based communities, mainly in the area of Ultra Mobile PCs. The first site in the portfolio is a forum about Dell Mini PCs called MyDellMini.com

Niggle Limited

Niggle specialises in providing customer feedback systems for businesses. They offer a comprehensive service which spans both the online and offline worlds, with everything from paper based postal feedback cards, to mobile / SMS and online feedback forms. In a recession consumers will be especially picky as to where they spend their hard earned cash, and we believe the best placed companies will be those that listen to their customers.

Bytewire Limited

Bytewire is a games development company run by Dave Heward and Elliot Reeve. They are working on a number of online multiplayer browser based games, the first of which is a Mafia type game called Street Crime. The game has been running for just over a month now, and already has 2000 players!

Renegade Games Limited

Renegade Games is another games development company run by Pete Zaborszky. The company is in the early stages of developing a number of projects, so watch this space for more information.