Nik's Technology Blog

Travels through programming, networks, and computers

Cisco CCNA Revision Notes

[updated - 6th April]I've just been going through files on my computer and giving it a bit of a spring clean in preparation for installing Windows Vista. As I was doing this I came across a Cisco folder containing more notes than I thought I had. When I get time I'll sift through them and post them in my Cisco section with the others, and add a link to them here.

In the meantime, thanks for all the nice comments and remarks I receive about my Cisco notes. If you're nearing your CCNA test I wish you the best of luck!

[newly published content]

Here's my CCNA cram sheet: Cisco CCNA pre-exam cram sheet

Windows Vista Upgrade

I finally received my Vista Home Premium upgrade DVD this morning. I got an email claiming it was being shipped earlier this month and commented on my thoughts here.

Unlike the retail versions of Vista you don't get the snazzy clear box with the rounded corner. I can't complain though, it came in a clear DVD case with a quick start guide and a new OEM Certificate of Authenticity (CoA). You may remember I bought a copy of Media Center 2005 with a Vista Upgrade voucher last year.

It also comes with a slip of paper that states the following:

Licensed Device. This Windows Vista software replaces the Microsoft Windows XP software that is eligible for the upgrade to this software. You may install and use this software only on the device on which you acquired the Windows XP software.

Reassignment to Another Device.

You may not reassign the license for this software to another device.

It also goes on to talk about transferring to a third party and support services.

This goes someway to answering some of my questions. When I get around to installing Vista I'll no doubt be adding some more posts here. I need to give my hard drives a spring clean before I can do that though ;-)

Adsense and Amazon's New Context Links Beta

I received an email from Amazon Associates yesterday explaining their contextual adverts are now out of closed beta and are now available for their associates to use (although still in beta).

I checked out the demo sites they mentioned, looked at the source HTML and logged into the Associates homepage to see what customisations were available.

All it requires is a few Javascript includes at the foot of the page and all the rendering is done client-side. Essentially any word(s) on your page can be linked to Amazon or Amazon Marketplace items, and they're all relevant!

No More Manual Links!

Hold your horses! Those of you who are Adsense publishers beware! I have been reading Adsense terms and conditions and some blog posts and I'm pretty sure you can't use Adsense and Amazon Context Links ads on the same page.

Does anyone have Google's official stance on this?

What about Amazon's terms and conditions? Do they have similar terms concerning competitor contextual ads?

At the end of the day, you can't blame Google from wanting to hold on to it's huge Adsense publisher network.

Media Center Extender - Network Congestion

Media Extenders are particularly useful for streaming video to your TV. Here in the UK the only available Media Extenders you can purchase come in the form of an Xbox 360.

I have been using my Xbox 360 to stream movies stored on my main Media Center PC to my living room over a wireless network (802.11g).

Occasionally I get a "Network Congestion" message appear in the top-right-hand corner, which comes accompanied with a small amount of picture judder/stutter. It's still highly watchable, just a little annoying. Information is available to help you improve your wireless performance; however the crux of the issue is the wireless standards. The Xbox wireless networking adapter supports the following WLAN standards 802.11a, 802.11b and 802.11g. The 802.11n standard has not been ratified by the IEEE yet, but when it comes around it will improve the throughput of data.

The Xbox 360 wireless networking adapter doesn't support any draft version of the 802.11n standard however, so we are stuck with 802.11a,b,g, unless we run an ethernet cable from the router to the Xbox, but that kind of defeats the object, doesn't it?

Microsoft recommends the following:

  • Only have 1 wireless route between your PC -> Router -> Media Extender
  • Use 802.11a standard as it works at 5GHz compared to the congested 2.4GHz channel
  • Use a router designed for Windows XP Media Center Edition

I fairly certain 802.11a is not legal in the UK, can anyone confirm this?

Where does Apple TV leave the Xbox 360?

Apple have just released Apple TV, essentially a device used to wirelessly bridge the gap between iTunes on your computer (Mac, PC) and your TV set in your living room.

Apple added video downloads to the iTunes service a while back, by getting several Hollywood studios on-board. These videos have so far only be available to watch on your computer screen or on your iPod video. Apple TV aims to fix this, by allowing your iTunes library to be wirelessly streamed to your HDTV.

Xbox 360's Media Capabilities

Microsoft on the other hand have similar strategies on invading peoples' living rooms with digital content, theirs though, is in the form of the Xbox 360, which as well as being a high definition games machine is also a very capable Media Center Extender.

As a Media Center Extender it wirelessly streams content from Windows Media Center, or Windows Vista (Home Premium and Ultimate editions) computers. If you don't have a Media Center edition of Windows you can still stream your music, pictures and just recently WMV videos too from the Xbox console using Windows Media Connect.

So How Do Apple TV and Xbox 360 Compare?

Ok, here's a matrix comparision table between Apple TV and the Xbox 360, so you can make your own mind up.

Apple TV
Xbox 360
HD Games Machine
Stream Audio
Stream Video
Stream Photos
Component Video
Audio Out
Yes (optical and RCA analogue)
Yes (optical and RCA analogue)
Ethernet connection
Wireless capabilities
Yes (built-in) (pre-n)
Yes (sold separately) (a, b, g)
HD Resolution capabilities
1080i, 720p, 576p, or 480p 1080p, 1080i, 720p, 480i,480p
DVD player
HD DVD player
Yes (sold separately)
iTunes compatibility
Remote control
Yes (sold separately)
HD drive
20GB (premium package only, not needed for streaming)
Video formats supported
H.264 and protected H.264 (from iTunes Store): Up to 5 Mbps, Progressive Main Profile (CAVLC) with AAC-LC audio up to 160 Kbps (maximum resolution: 1280 by 720 pixels at 24 fps, 960 by 540 pixels at 30 fps

iTunes Store purchased video: 320 by 240 pixels or 640 by 480 pixels

MPEG-4: Up to 3 Mbps, Simple Profile with AAC-LC audio up to 160 Kbps (maximum resolution: 720 by 432 pixels at 30 fps)
WMV only, although a Windows 3rd party app called Transcode360 will allow most other formats to be streamed
Audio formats supported
AAC, protected AAC (from iTunes Store), MP3, MP3 VBR, Apple Lossless, AIFF, WAV MP3, WMA, un-encoded AAC, CD, DVD audio

Contact forms, SPAM relay email and the CAPTCHA

Back in January this year I decided enough-was-enough with increasing amounts of automated SPAM coming into my inbox and originating from my site. I decided to do something about it. My contact form has been attracting lots of SPAM bots which were trying their best to relay their SPAM through my site.

My form has always had the To: and From: fields hard-coded however, so I doubt anything ever got relayed, but they all got sent to me anyhow.

As a result I now verify that the form was actually filled in my a HUMAN each time the form gets sent! I've built an ASP CAPTCHA function to achieve this (Completely Automated Public Turing test to tell Computers and Humans Apart), more about CAPTCHAs here.

Accessibility and CAPTCHAs

There are however down-sides to this SPAM free existence. CAPTCHA images in the form that I am using are inherently inaccessible, so I intend to use another system in conjunction with my image CAPTCHA as used my Matt Cutts on his blog.

Recruiting Web Developers - Finding the right coder!

I've had a fair bit of experience employing web developers in recent years, I've also read a fair number of CVs, and posted a number of online adverts.

With recent changes to UK employment law it's more difficult than ever to attract the right candidates and get them to apply, as well as successfully convince the wannabe developers that a particular post isn't for them.

I've read a couple of articles today that interested me concerning recruitment. This article about writing a resume for developers shared some useful tips about writing CVs, most of which I can definitely recommend judging by the CVs I receive.

The second article I read, (but can't find the link!) talks about a novel way of advertising for web developers, advertise in your HTML source code of course! Only developers would look there of course, so you're audience, however small, is highly targeted.

I'd like to add to the list of what not to do while trying to secure an interview:

  • Don't SPAM companies with your CV - once is plenty for each position
  • Don't include SPAM/holding domains/dodgy sex domains on your CV unless you're applying for a job in this area
  • Do we really need to know what your late Father's name was?
  • Your National Insurance number is not necessary - haven't you heard of ID theft?
  • Weird lists of hobbies which are unrelated to the job you're applying for
  • Any lack of formatting, mixtures of fonts, font sizes, colours
  • Is a photo of you really necessary?

Cisco CCNA hands-on experience

It's been a while since I completed my CCNA course, but I've been thinking about the course recently, partly because I'm having a clear-up and I've decided to sell the Cisco 2501 router I bought to practice IOS commands on. I've also given my website a bit of a redesign and I got looking over my CCNA notes again.

I attended evening class at my local college for several years, one night a week to learn about networking through Cisco's online e-learning site. The course was thorough and included hands-on router lab experience, fault-finding etc. Subsequently when I took the exam I got a high score.

What baffles me is the fact that you get adverts on Google for 2 week intensive courses in India. How can anyone possibly learn the whole course material in 2 weeks?? Perhaps if you are already an IT professional and just wanted the certification, but a networking newbie? Beats me!

Site Redesign and Upgrade

I've finally decided to give my site a face-lift. I first built it in 2002 when the web was a different place, just recovering from a boom and bust. Since then we've seen the dominance of Internet Explorer errode slightly somewhat with the emergence of Firefox/Mozilla, Safari and Opera. Browsers have also become more standards compliant, which has made it easier to build cross-browser sites.

Advances in browser rendering engines have made it possible for more and more sites to adopt XHTML with CSS 2.0 stylesheets with presentation specific HTML consigned to the dustbin.

Moving all presentation logic to CSS is a liberating step to take, but it requires different skills and techniques compared with using tables. It's very powerful, but it also has its faults. Where before you had no option but to use JavaScript to create certain effects, often called Dynamic HTML, now a lot of those rollovers etc can be handled by a Cascading Style Sheet.

I've created a design that follows the current web vogue often associated with so called Web 2.0 sites, I'm still testing and fine tuning the design and initial template, but it will encompass this blog and my whole site, it'll be XHTML compliant using the WC3 strict DTD, my CSS will handle all presentation logic and I will aim to make it as accessible as possible to screen reading devices.

Windows Home Server

I signed up to test the new Windows Home Server Public Beta a while back and received an invitation to download and review it.

Like a lot of people I am frequently running out of storage space on my machines and needing to upgrade. I am also fairly concerned about data backups too, so much so that I upgraded my main machine a while back to include a SATA RAID 1 mirror for my core data over 2 x 320GB drives.

Most people however don't have the need or knowledge to set up a decent backup or redundancy solution, so Windows Home Server when purchased installed on a piece of purposely designed hardware should fill this gap in the market.

When I get a spare few minutes I'll download the DVD and test on an un-used machine. I'm particularly interested in the usability of the software since it will mostly likely be bought by and used by people who are not particularly technically minded.

From what I've heard it does not include Media Center (since it's a headless OS), but it features Windows Media Connect, so I'll be able to stream my music and video straight to my XBOX 360 without having to have my main machine running.