Tag: Best Posts

EC2 and IP Addresses

One of the exciting things about having a cloud computing service is how to talk to the rest of the world. It’s all very well to have a varying number of machines in various locations, but you need constant DNS names at least (and sometimes constant IP addresses) to do most useful things. I have […]


Basics of EC2

I have previously written about my work packaging the tools to manage Amazon EC2 [1]. First you need to login and create a certificate (you can upload your own certificate – but this is probably only beneficial if you have two EC2 accounts and want to use the same certificate for both). Download the X509 […]


Integrity and Mailing Lists

One significant dividing factor between mailing lists is the difference between summary lists (where the person who asks a question receives replies off-list and then sends a summary to the list) and the majority of mailing lists which are discussion lists (where every reply goes to the list by default). I have seen an argument […]

Misc Computer

Upgrading a server to 64bit Xen

I have access to a server in Germany that was running Debian/Etch i386 but needed to be running Xen with the AMD64 version of Debian/Lenny (well it didn’t really need to be Lenny but we might as well get two upgrades done at the same time). Most people would probably do a complete reinstall, but […]


Kernel issues with Debian Xen and CentOS Kernels

Last time I tried using a Debian 64bit Xen kernel for Dom0 I was unable to get it to work correctly, it continually gave kernel panics when doing any serious disk IO. I’ve just tried to reproduce that problem on a test machine with a single SATA disk and it seems to be working correctly […]


Programming and Games for Children

The design of levels for computer games is a form of programming, particularly for games with deterministic NPCs. It seems to me that for a large portion of the modern computer user-base the design of games levels will be their first experience of programming computers, the people who don’t start programming by creating games levels […]


Some RAID Issues

I just read an interesting paper titled An Analysis of Data Corruption in the Storage Stack [1]. It contains an analysis of the data from 1,530,000 disks running at NetApp customer sites. The amount of corruption is worrying, as is the amount of effort that is needed to detect them. NetApp devices have regular “RAID […]

Misc Computer

EC2 Security

One thing that concerns me about using any online service is the security. When that service is a virtual server running in another country the risks are greater than average. I’m currently investigating the Amazon EC2 service for some clients, and naturally I’m concerned about the security. Firstly they appear to have implemented a good […]


RPC and SE Linux

One ongoing problem with TCP networking is the combination of RPC services and port based services on the same host. If you have an RPC service that uses a port less than 1024 then typically it will start at 1023 and try lower ports until it finds one that works. A problem that I have […]

Networking Security

Getting Started with Amazon EC2

The first thing you need to do to get started using the Amazon Elastic Compute Cloud (EC2) [1] is to install the tools to manage the service. The service is run in a client-server manner. You install the client software on your PC to manage the EC2 services that you use. There are the AMI […]