iPhone 2.0 screenshots (and why GPS on an iPhone is worthwhile)

Posted on By Mark Wilson

For a while now, there have been various third party screenshot utilities around for jailbroken iPhones but there is also a built in function in the iPhone 2.0 software (I haven’t tried on earlier versions). Just press the home and sleep keys together, the screen will briefly flash which, and a .PNG file will be created in the camera roll. Then hook the iPhone up to a computer with the supplied USB cable and use your chosen application to download the picture to the computer (just as you would for camera images). (via Alex Coles)

iPhone screenshot with GPS traceThe example image in this post showing the GPS trace for where I am sitting right now… and it’s only about 4 metres north-east from where I really am. For those people who say that GPS on the iPhone is unnecessary I’d point out that it’s a lot better than my v1.1.4 iPhone which thought I lived in a field about a mile and half south-east of here…

If I’m going to use location-aware services, I’d like them to be aware of where I am (rather than where the local farmer’s sheep are). That’s why GPS in an iPhone is worthwhile – regardless of time it takes to lock on (which seems to be a very long time) and the conseqential hit on battery life.

Microsoft infrastructure architecture considerations: part 6 (high availability)

Posted on By Mark Wilson

In this instalment of the series of posts on the architectural considerations for designing a predominantly-Microsoft IT infrastructure, based on the MCS Talks: Enterprise Infrastructure series, I’ll look at some of the architecture considerations relating to providing high availability through redundancy in the infrastructure.

The whole point of high availability is ensuring that there is no single point of failure. In addition to hardware redundancy (RAID on storage, multiple power supplies, redundant NICs, etc.) consideration should be given to operating system or application-level redundancy.

For some applications, redundancy is inherent:

  • Active Directory uses a multiple-master replicated database.
  • Exchange Server 2007 offers various replication options (local, clustered or standby continuous replication).
  • SQL Server 2008 has enhanced database mirroring.

Other applications may be more suited to the provision of redundancy in the infrastructure – either using failover clusters (e.g. for SQL Server 2005, file and print servers, virtualisation hosts, etc.) or with network load balancing (NLB) clusters (e.g. ISA Server, Internet Information Services, Windows SharePoint Services, Office Communications Server, read-only SQL Server, etc.) – in many cases the choice is made by the application vendor as some applications (e.g. ISA Server, SCOM and SCCM) are not cluster-friendly.

Failover clustering (the new name Microsoft cluster services) is greatly improved in Windows Server 2008, with simplified support (no more cluster hardware compatibility list – replaced by a cluster validation tool, although the hardware is still required to be certified for Windows Server 2008), support for more nodes (the maximum is up from 8 to 16), support for multiple-subnet geoclusters and IPv6 as well as new management tools and enhanced security.

In the final post in this series, I’ll take a look at how to build an infrastructure for data centre consolidation.