Monday, June 26, 2006

Another hard disk dead

I had a Freecom Classic Mobile HD 2.5" 40Gb external USB hard drive on which I had installed Office 2007 & VS2005. It stopped working today despite only having bought it a couple of months ago.

Tuesday, June 20, 2006

Desktop background

Here is my favourite 1900 x 1200 photo of Meribel that I took earlier this year. Feel free to use it as your desktop background.

Download File

Monday, June 19, 2006

10GBaseT & Cabling Standards

Last week I was at the British Standards Institute TCT7 committee meeting reviewing several important changes to the UK & European cabling standards. I thought I would provide a quick summary, if you would like any further details please ask.

10GBaseT – Ethernet Standards
The IEEE have finished the 10 Gigabit Ethernet over copper cabling standard on time and it will be officially published very soon. However there is widespread concern that important elements have been omitted in a rush to finish the standard “on time”. Please remember the 10GBaseT standard is an electronic protocol standard NOT a cabling standard. 10GBaseT will support a channel length of 100m over Cat 6 FTP and Cat 7 FTP (both available today) and over 100m of Cat6a UTP (in the future – standard work is just starting now). The chipset manufacturers are having problems with the large amount of power needed for each chip. They currently need about 15W per port, unfortunately the chips themselves will only support 4W without overheating. As a result the pre-production chips are having to be manufactured in a larger package so they can disperse the heat better. The amount of power required is a big concern as a typical 24 port 1U switch will get very hot and thus un-reliable. The electronics industry is hoping that by making the chips smaller they can reduce the heat output, unfortunately this technology is not currently available but should be within 4-5 years. Some manufacturers have introduced pre-standard chipsets but they do not work with each other as they use different techniques to reduce power requirements. The current non-standard chipsets have only been able to manage a 30m link over Cat 6 as these can be produced more easily as they do not need as much electronics and so stay cooler. There is significant work to do before 10GBaseT becomes mainstream, do not expect widespread desktop deployment for 5-7 years.

European Cabling Standards
Firstly it’s important to remember that there are two cabling standards the American TIA/EIA who define Cat 5, Cat 5e, Cat 6 and will define Cat 6a in the future. The rest of the world uses the ISO 11801:2002 Class D, Class E (and Class Ea in the future) series of standards. Until now Cat 5e and Cat 6 have been almost identical to Class D and Class E however the American Cat 6a standard is looking as though it will be much less stringent than the Worldwide Class Ea standard. This problem of Cat 6a not being equal to Class Ea is a big issue that will hopefully be resolved before either standard is published. The very earliest these standards could be published is Q2 2007 but this would mean several important items would have to be left out and added later.

Official work on the cabling standard could not start until the 10GBaseT standard was published. Today we reviewed some of the proposed amendments to ISO 11801:2002 to add Class Ea limits. The amendments proposed will probably be rejected by the UK committee because they are very incomplete and in places simply wrong. Some of the cabling manufacturers are pushing to get this amendment published to support their “10Gig” product story. However the amendments include parameters for the “Channel” only, there are no “Permanent link” limits. This has been done in an attempt to speed up the process, adding permanent link parameters will take an extra 12-18 months. Without any “Permanent link” limits there will be nothing that installers can use to test a system. In my view there is no point publishing a new standard if it does not have any parameters that can be used to test against. The standard needs to be done properly with both channel and permanent link limits, it is likely that this process will take until at least Q2 or Q3 2008.

Any cable manufacturer pushing a “10 Gig” story now is really selling something that is still 18-24 months from being completed. (and that assumes everything goes to plan... history shows that this seldom happens and the process will take much longer)

XML Test Result Export
My initiative to create a standard file format for exporting test results from handheld testers is now a European EN50346 draft format and will be fully reviewed at the September meeting.