Posts by Stephen Beynon

9 posts • joined Thursday 24th May 2007 12:08 GMT

Posted in US Navy preps railgun for tests

Posted Thursday 9th February 2012 19:07 GMT

Stephen Beynon

No need for a reactor

There is no need for a Nuclear reactor. Any ship with electric propulsion will have bloody large generators on board that can charge the rail gun capacitor bank.

Posted in But it said so in the manual

Posted Tuesday 28th September 2010 20:20 GMT

Stephen Beynon

Linux with 1 Billion files

Linux seems to scale far better than windows with large numbers of files. This article on LWN covers experiments to put 1 Billion files onto linux filesystems.

http://lwn.net/Articles/400629/

The basic conclusion is you can put 1 Billion files on a linux filesystem, but you require a lot of memory to check the filesystem (10-30 GB depending on filesystem type) That is far less than the requirement listed above for a mere 60 million files on Windows.

Posted in Linux kernel purged of five-year-old root access bug

Posted Friday 20th August 2010 11:05 GMT

Stephen Beynon

An X design flaw surely

The root exploit works because the X server (running as root) allows unprivileged process to direct access to its memory space, and permits those unprivileged processes to allocate so much memory that it gets dangerously close to the stack. The X server also allows those processes to send commands causing the X server to use large amounts of stack space.

This sounds entirely like a design flaw in X to me. The new kernel stack guard page is a good way of protecting against this design flaw (and other similar ones in as yet unknown programs). It would have been nice if the kernel stack guard had happened 5 years ago when a possible weakness was identified.

It is worth noting that the stack guard reduces the exploit from being a root exploit to being a X server crash (with SIGBUS) so it is still a denial of service attack in X.

Posted in India's Reva to pitch 'invisible' e-car reserve battery

Posted Tuesday 8th September 2009 13:49 GMT

Stephen Beynon

Battery Warrenty Issues

The batteries tend to last longer if you never let them fully discharge, so the real reason for keeping a reserve is to maintain battery life. Clearly it is good PR/customer service to let the customer tap that reserve rather than being stuck by the side of the road with a dead car.

I imagine the reason that they make it require a text message to enable the reserve it to stop people using the reserve every journey, and killing the battery would lead to unacceptable warrenty claims and a bad reputation for battery life time.

Posted in Date bug kills VMware systems

Posted Tuesday 12th August 2008 14:43 GMT

Stephen Beynon

@AC Testing for date problems

Testing for date problems is not exactly rocket science. I would suggest having a list of random dates you try during testing. In addition to that have several systems running with dates set in the future in test. Maybe 1 week in the future, 3 months in the future and 6 months. Hopefully the 3 and 6 month systems will catch date related bugs before shipment. The 1 week system will give you 1 weeks warning of a test escape.

I wonder why VMware did not do this.

Stephen

Posted in Virgin Media in premium rate U-turn

Posted Thursday 20th March 2008 14:09 GMT

Stephen Beynon

To be fair

Every time I have called the 25p/min support line (4 times) the cost of the call has been refunded, because the problem has been their fault. I did not know this would happen before my first call, so I can see why people would be annoyed about the idea of having to pay to report a fault.

Posted in Lenovo ThinkPad T61

Posted Sunday 17th February 2008 01:01 GMT

Stephen Beynon

Active Protection

The Thinkpad Disk protection works by having an accelerometer in the laptop to detect if the laptop goes into free fall (i.e it is dropped). It then parks the hard disk while the laptop is in mid-air. I am not sure what hard drives Thinkpads currently use, but the Seagate datasheet states that their drives are good for a 250G shock while operating or a 900G shock when they are not operating. This significantly increases the chances of your data surviving the impact, even if the laptop does not.

Posted in Spam King arrested in Seattle

Posted Thursday 31st May 2007 17:13 GMT

Stephen Beynon

SPF

Andy: since I enabled spf on my domains I have had a vastly reduced number of bounces from messages that were faked from my domains. While spf is by no means perfect it has helped me.

Stephen

Posted in Fancy a nuclear power station in your backyard?

Posted Thursday 24th May 2007 12:14 GMT

Stephen Beynon

No reactors up north

I believe that most of the North-South electricity lines are running at close to maximum capacity taking electricity South, so I am assuming that if Scotland were to pick up more nuclear powerstations that more pylons would be required to bring the power south. I can see that being popular .....

As for the cooling towers - it is rather important to keep a nuclear reactor cooled, so I assume that there would have to be sufficient towers to keep the reactor cool even if some were out of action, or some way had been found to use the waste heat elsewhere.