* Posts by Chris Lewis

13 publicly visible posts • joined 1 Jun 2008

RSA says it fathered orphan credential in Firefox, Mac OS

Chris Lewis

Breaking: it's valid

The latest news, according to this mozilla.dev news group thread, is that the certificate is valid:



Breaching Fort Apache.org - What went wrong?

Chris Lewis

@Anonymous Coward, 20:46

Oh hay, armchair admin!

Fancy posting the addresses of all the systems you're responsible for online, so that interested parties can check you're following all the "best practice"?

No? Didn't think so.

Apache are to be commended for coming clean, making amends, and explaining their policy in the way that they have.

Fake ATM scam rumbled by Defcon hackers

Chris Lewis

Re: "Why so soon." and "Why are the powers that be so thick?"

Well, pretty clearly there's no need for them to return if they can send the information they need home.

I read an interesting comment on a Wired article on this subject from an attendee who suggested there was a legitimate machine directly adjacent that was reporting a network fault. He suspected that the dodgy ATM might have been ferrying back the details over a network connection stolen from the other machine, which seems perfectly reasonable.

Cutting the cord: future mobile broadband tech

Chris Lewis


In the process of trying to make OFDM more palatable to a non-comms audience, you seem to have missed the real advantage of the technique. The real beauty of OFDM is the flexibility given by so many orthogonal low-bandwidth sub-carriers: you can avoid the problem of frequency-selective fading for one user (mitigating their bad channel) by moving their allocation in the spectrum. This leads to much more efficient usage of spectrum, and better channels for all. It is excellent at adapting to nasty channel conditions in slowly-changing channels*.

I'm not really sure what you're getting at with regards to "solving" the problem of "timing". If you're referring to inter-symbol interference, which is indeed a concern, then OFDM doesn't directly solve this by "putting [chunks] in different frequencies" - but what it does do is ensure that the symbol rate on each individual component frequency is low enough that ISI can be mitigated easily. But if you're referring to interleaving, which does indeed spread "chunks" of data amongst frequencies, then that helps solve a different problem: the issue of losing bursts of data in frequency-specific fades.

On the down side, OFDM really isn't good in channels with a great deal of doppler shift (since it breaks the orthogonality between the sub-carriers) - making it non-ideal for use in fast-moving vehicles, for instance, without specific counter-measures.

Remembering the true* first portable computer

Chris Lewis

Great article.

That's all.

Samsung unsheathes screaming phone

Chris Lewis

@those being pedantic about dB 'db' usage

Oh please, it's quite clear from context that it refers to an SPL ratio. But yes, it should be a capital 'B'.

In a circumstance where there might be some ambiguity between the units in use (in radio emissions, for instance), then your "concern" might be justified. But in this case it's sound, and failing some conspiracy to confuse you, that means it's SPL.

Brit, French nuke subs collide - fail to 'see' each other

Chris Lewis

Thanks again...

for cutting through the popular churnalism to the facts, El Reg!

Microsoft axes 5,000 staff as Q2 profit dives 11%

Chris Lewis

Re: percentage

As of 2008, nearly 90,000 employees globally: http://blog.seattletimes.nwsource.com/techtracks/2008/06/microsoft_head_count_way_up_in_last_11_months_near.html

So 5.6%, if I must do the maths. :-)

Intel stuffs Nehalem chips with joy

Chris Lewis
Thumb Up

Turbo Mode...

Glad to see it making a comeback.

I hope all new PCs with these chips come equipped with the venerable "turbo button" again, and a seven-segment display, preferably in green, for debugging said mode.

Exploit code for Kaminsky DNS bug goes wild

Chris Lewis

Stealing your money?

"When they typed bankofamerica.com into their browser, they'd have no way of knowing whether they were being directed to the real site or one designed to steal their money."

No way of knowing? Try SSL.

If your bank is relying on DNS to prove their identity for online banking, then it's time to take your cash somewhere else.

UK.gov tells throttling petition: Choke on it

Chris Lewis

re:re:Should I?

You sine it, and I'll cosine it.

iPhone 3G to be in 'very short supply for weeks' - carrier

Chris Lewis
Dead Vulture

Blaming Apple? Try not using AJAX next time

It's pretty clear O2 didn't do their sums at all, or they would've gone for something other than a totally overkill AJAX RIA and all the server-side state handling those entail.

I'd gladly have stared at the world's most boring, CSS-free, table-ridden Web 1.0 form if it actually let me place an order or, at the very least, use my browser "back" button.

Japanese woman moves into bloke's closet

Chris Lewis

@Nick Ryan

Using ^W instead of ^H might save you some time in the future.