“What is post-PC”?

The market is changing. PCs are lasting longer, and people are finding acceptable utility in replacing casual-use, low-end PCs with smartphones and tablets.

Again, it’s about the total compute time across all of society. The PC is just becoming a smaller chunk of a larger whole, the majority of which will be post-PC devices.

via “What is post-PC”? — The Post-PC FAQ | The Platform.

Which SSL certificate should I buy?

SSL certificates that most web browsers can accept without grief are sold by a relatively small number of companies. That’s because the major web browsers are shipped with a certain set of “root certificate authorities” that they trust… and if your certificate isn’t signed by one of those authorities, or by a certificate “chained” from one of them, then you’re out of luck— the web browser will display a scary warning to the user or, in some cases, refuse to work with your site at all.

The cost of SSL certificates varies quite a bit, from as little as $20 to as much as $1,000 or more. Why such a big difference? There are three main reasons:

via WWW FAQs: Which SSL certificate should I buy?.

2. Some certificates are directly signed by a trusted root certificate, while others are “chained” from another “intermediate” certificate. This isn’t really a problem, as long as the company selling you the chained certificate really does own the root certificate. But some webmasters get confused by intermediate certificates, fail to install them correctly, and mistakenly think they have purchased a bad certificate. So chained certificates are usually less expensive to allow for this inconvenience, even though there is no real technical disadvantage.

MQTT: MQ Telemetry Transport

MQTT stands for MQ Telemetry Transport. It is a publish/subscribe, extremely simple and lightweight messaging protocol, designed for constrained devices and low-bandwidth, high-latency or unreliable networks. The design principles are to minimise network bandwidth and device resource requirements whilst also attempting to ensure reliability and some degree of assurance of delivery. These principles also turn out to make the protocol ideal of the emerging “machine-to-machine” (M2M) or “Internet of Things” world of connected devices, and for mobile applications where bandwidth and battery power are at a premium.

via FAQ – Frequently Asked Questions | MQTT: MQ Telemetry Transport.

I see RIM phones using this.

Are there standard ports for MQTT to use?

Yes. TCP/IP port 1883 is reserved with IANA for use with MQTT. TCP/IP port 8883 is also registered, for using MQTT over SSL.


Pacemaker keeps your applications running when they or the machines they’re running on fail. However it can’t do this without connectivity to the other machines in the cluster – a significant problem in its own right.

Rather than re-implement the wheel, Pacemaker supports existing implimentations such as Heartbeat. Heartbeat provides:

  • a mechansigm to reliably send messages between nodes,
  • notifications when machines appear and disappear
  • a list of machines that are up that is consistent throughout the cluster

Heartbeat was also the first stack supported by the Pacemaker codebase.

via FAQ – ClusterLabs.

Virtual Disk Development Kit FAQ

VI API is a Web Service and XML interface focused on management of virtual machines and ESX server configuration.

VCB offers command-line tools to integrate with backup products on SAN.

The VDDK is focused on efficient access and transfer of data on virtual disk storage. The VDDK can be used in conjunction with other APIs to offer a complete integrated solution for management of virtual infrastructure.

via Virtual Disk Development Kit FAQ.