iStock keywording rant

A few months ago I've decided to start contributing to iStock. I'm not much of a photographer, but the thinking was: I can get to some places which might be interesting for others.

So I've started uploading pics of pretty datacenters, 10Gig switches and the likes. And keywording these accurately for what they are, being as specific as I can.

One thing I've noticed from the most downloaded photos is that they have all the keywords in the world, which have nothing to do with the photo, kinda like websites in the early 2000's having everything up to and including 'sex' and 'mp3', because they were popular search term.

The title pic is a very nice patchpanel, from the Signature collection of iStock.
Now let's check out its keywords:

Computer Network, Node, Cable, Fiber Optic, Router, Computer Cable, Communication, Wireless Technology, Business, Telecommunications Equipment, LED, Network Connection Plug, CPU, Control Panel, rj45, Control Room, isp, Power Line, Internet, data center, Computer Part, access point, Equipment, Light - Natural Phenomenon, Close-up, Wired, Network Security, Network Server, Modem, Rack, Midsection, Number, Connection, Support, Concepts, White, Blue, Black Color, Ideas, Technology, Macro, Computer

Most of them are far fetches, the weirdest are in highlight. Is this any use to anybody at all, from the buyers side? Buyers really never search for specific terms and they never know anything about the brands/devices they're looking for? I'm not that convinced, but I'm a novice on the platform, so maybe so. Comments are most welcome.

In the meantime, I've started to collect brand-specific lightboxes, maybe they'll be some use to some folks:

Cisco switches lightbox
HP switches lightbox

How to deny Postfix SMTP authentication from non-US clients

As the war on spam continues, one of my clients wanted to only provide SMTP AUTH capabilities to IP addresses in the states, as their employees are only located there anyway.

Postfix has a facility for this, called smtpd_sasl_exceptions_networks. It basically denies SASL auth to IP's from the specified ranges. Disregarding IPv6 for now, here's a list of IP ranges from IANA that are non-US (ARIN) allocations:

smtpd_sasl_exceptions_networks = 0.0.0.0/7
  2.0.0.0/8
  5.0.0.0/8
  10.0.0.0/8
  14.0.0.0/8
  25.0.0.0/8
  27.0.0.0/8
  31.0.0.0/8
  36.0.0.0/8
  37.0.0.0/8
  39.0.0.0/8
  41.0.0.0/8
  42.0.0.0/7
  46.0.0.0/8
  49.0.0.0/8
  51.0.0.0/8
  53.0.0.0/8
  57.0.0.0/8
  58.0.0.0/7
  60.0.0.0/7
  62.0.0.0/8
  77.0.0.0/8
  78.0.0.0/7
  80.0.0.0/4
  101.0.0.0/8
  102.0.0.0/7
  105.0.0.0/8
  106.0.0.0/8
  109.0.0.0/8
  110.0.0.0/7
  112.0.0.0/4
  133.0.0.0/8
  141.0.0.0/8
  145.0.0.0/8
  150.0.0.0/7
  153.0.0.0/8
  154.0.0.0/8
  163.0.0.0/8
  171.0.0.0/8
  175.0.0.0/8
  176.0.0.0/4
  193.0.0.0/8
  194.0.0.0/7
  196.0.0.0/7
  200.0.0.0/6
  210.0.0.0/7
  212.0.0.0/7
  217.0.0.0/8
  218.0.0.0/7
  220.0.0.0/6

ARCH Linux on a WM8850-based mini laptop

One of my purchases earlier this year was a mini laptop, powered by a Wondermedia WM8850 chip.

It's kinda handy: runs Android/Linux selectively, has a HDMI interface, wired Ethernet and fullsize USB 2.0 ports. Also, it can be charged from USB, tablet style.

Quirks include no HDMI on Linux (yet), and it takes a bit of effort to turn on the wireless. Missing the gpio binary, you can get there by using the sysfs interface:

echo 6 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio6/direction
echo 1 > /sys/class/gpio/gpio6/value

Just echo 0 there to turn it off again.

Compiling a kernel needed some scraping on the web, but can be done like this:

cd linux-3.16
nice make ARCH=arm menuconfig
nice make ARCH=arm zImage
cat arch/arm/boot/zImage arch/arm/boot/dts/wm8850-w70v2.dtb > arch/arm/boot/zImage_w_dtb
mkimage -A arm -O linux -T kernel -C none -a 0x8000 -e 0x8000 -n "My Linux" -d arch/arm/boot/zImage_w_dtb ~/uzImage.bin
make ARCH=arm modules
sudo make ARCH=arm modules_install

The kernel config is online here.

It works happy with a 8GB SD card and adding a bit of swap can't hurt as the 512MB of RAM is not that much.

Thanks for the vt8500 developers!

HTML5 video live streaming with ffmpeg and mediaelement.js, Round 2

Follow-up from this summer to the original post.

So, after not rolling out our HTML5 player last year, we've decided to give it a go again this year.
What we've learned: things have changed in Internet-land.

IE no longer requests or supports WMV anymore, which is weird but actually correct. It takes mp4 now as default.

Chrome was still ticking along happy.

Firefox was a big surprise: between version 19 and 20 they've reworked the HTTP engine, so it's a bit quirky now:

• It fetches the first 8k for metadata in a request
• It uses HTTP 206 Partial content requests now
• If it doesn't get an X-Content-Duration, it'll send a new partial request for the end of the file. As it's transcoded on the fly, this is bad for us.

So, we need to give it:

• HTTP 206 headers
• Range headers
• X-Content-Duration headers (in seconds)

This can be done with something like this:

$ua=$_SERVER['HTTP_USER_AGENT'];
$useragent='generic';
# match Firefox 1-19
if ( preg_match('/Gecko.20.*Firefox.(1){0,1}[0-9]\./', $ua) ) {
    $firefox19=true;
}
# match all Firefox
if ( preg_match('/Gecko\/.*Firefox.[1-9]/', $ua) ) {
    $firefox=true;
}
# if Firefox 20-
if ($firefox && !$firefox19) {
    $useragent='ff20';
}

# generic headers
if ($useragent=='generic') {
#header("HTTP/1.1 200 OK");
#header('Content-Disposition: attachment; filename=' . basename($file));
}

# firefox 20+ headers
#   firefox 20 wants partial content with code 206, and likes X-Content-Duration
if ($useragent=='ff20') {
header("HTTP/1.1 206 Partial Content");
header("Range: bytes=0-");
header("X-Content-Duration: $totduration");
}

I couldn't get the Flash fallback of mediaelement.js working and Silverlight was killed by Microsoft, so mediaelement.js was taken out from our setup, with a manual Flash fallback link.
We've also noticed A-V sync issues with ffmpeg, so deployment was pulled again, but we're making progress.

Thanks to Browserstack, for making life easier while testing.

Linux, Network and Datacenter contractor/freelance engineer in Dublin

New year, new-old adventures:

I'm moving back to the contract/freelance market, this time in Ireland. I'll be available as a Linux, networking and datacenter engineer in Dublin and Shannon (as necessary).

Certified to work on the following kit (the list is not exhaustive):

- Cisco

- Juniper

- Brocade

- HP

- D-Link

- Zyxel

For the full list and to contact, please check out my LinkedIn profile.

I'm happy to work through Elance, as it provides protection to all parties.

I have a nice Experts-Exchange profile as well.

Edit:

Now we do Facebook as well!

Edit2:

The website is live: d8ns.com.