* Posts by Ken Ryan

6 publicly visible posts • joined 13 Apr 2008

NASA working on boomless supersonic jets

Ken Ryan

Re: How about the aero-dynamic equivalent of supercavitation?


Supercavitation is solving the problem of high friction between the water and the surface of the weapon. While a supersonic aircraft feels the effect of air friction it is nowhere near the limiting factor in its speed nor does it have anything to do with the sonic boom.

A sonic boom comes about because air is getting compressed ahead of the aircraft faster than it can get out of the way. The release of the compression waves behind the A/C is where the sonic boom comes from.

Changing the geometry of trailing structures - engines being the worst offender, the wings less so - helps the air compression waves release more gently.

This could find broad application commercially in several respects - reduction of noise in helicopters (rotor tips are usually supersonic), the windmills noted above, turbine blades, and so on.

Judge: No cryptographic hash analysis without warrant

Ken Ryan

@Chris C, et. al.

FYI, any modern disk drive (anywhere in the last 7-8 years or so) does logical block mapping all the time. It's not just SSDs.

Getting capacities up has required tolerances to be so small in the magnetic domains and mechanical alignments that read errors crop up constantly. The drive starts out with thousands of spare sectors, and logically maps them in as read errors crop up.

In addition, the notion of a fixed "sectors per track" is also outdated. Outer tracks are physically much longer than inner tracks, so many more sectors are written there (this became feasible once the read channel became much faster than the linear platter speed).

The traditional cylinder/head/sector numbering is pure fiction nowadays, present only because of a certain OS and the BIOSes which support it.

'Idiot' pulls cables, downs ISPs at Telecity

Ken Ryan

Life Imitates Art? Or vice-versa?

What I want to know is did the local BOFH use the CAT5-Mains adapter, or self-locking comms cupboard?

UK appeal court dismisses mod chip conviction

Ken Ryan


The newer WRT54G is based on VxWorks, which is not a Linksys OS - it's by a company called Wind River, and is a very popular real-time embedded OS.

Also, the Linux version continues to be available as WRT54GL.

MS supplies cops with DIY forensics tool

Ken Ryan

In-RAM analysis

The purpose is the software on the USB stick can take a snapshot of critical areas in system RAM before the computer is shut down - something like decrypted strings, passwords sitting on stacks, etc. If you shut down you lose that stuff.

Of course everyone who has ever stuck a thumb drive into a Windows box knows it fiddles and churns and loads drivers and fiddles with the registry in order to be able to say "your new hardware is ready to use", and only after that can anything on the drive be executed. So much for preserving an unadulterated hard drive image, even if you do get something useful from RAM afterwards.

Of course, as other posters have noted, disabling the USB ports is pretty easy. Heck, my wife's XP box did that all by itself!

This technology is only for "investigators" who understand neither computers nor evidence rules.

SanDisk warns that unsecured flash drives are coming to get you

Ken Ryan

Windows lockin

My company requires secured drives. Alas, my primary use is moving files among engineering development and lab computers - mostly Linux with a few Windows. The secured drives are Windows-only, at least the corporate-approved ones do not support Linux.