Blog about the Net, Pakistan and more

Saturday 20th September 2008

Huge bomb blast in Islamabad


Was shaken by a huge explosion a few minutes back. Felt like the building was about to come down, but initial reports indicate the bomb blast was at least a couple kilometers from where I am, around the Marriot Hotel area.

Must be a really big one to be felt so badly at such a distance and I hope the damage wasn't too great.


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Posted at 20:16pm PKST  Comments(4) |

Monday 8th September 2008

Recovering data from a shredded hard disk

Hardware Technology

Ever since I got into system administration, hardware security to narrow it down, I have been led to believe that virtually any data written on a hard disk drive can be easily recovered, even if the bits have been overwritten. This is the reason many organizations destroy Hard disk platter their old, perfectly good hard drives completely instead of discarding them whole.

Though I myself have recovered lost or deleted data a number of times, recovering overwritten or "zeroed" bits was something you would leave to data recovery services with the right hardware tools. The theory is that the data itself is binary, either a 1 or a 0, but when written on magnetic media, it leaves a pattern that can be extracted even if the values have been overwritten.

To be very safe with my own data, I've always "shredded" (using the shred or dd utilities) any hard disks that had any of my data and now needed to be returned or passed on to someone else. This involves writing random bits of data on the whole hard disk with up to 25 passes or cycles (default for shred) which can take quite a while on very large or slow drives and can possibly wear them down.

The Great Zero Challenge aims to confirm whether or not a professional, established data recovery firm can recover data from a hard drive that has been overwritten with zeros once. The challenge, which started on January 15th 2008, will expire in another four months yet not even a single contender has taken it up. The prize has been raised to $500 from $40, but I doubt anyone will step forward.

Reading up more on this, I've found that you require a powerful electron microscope to get any meaningful results and even then, the chances of recovering useful and complete data are very slim. So unless the government is after it, or your aging drive contains evidence of which planet Michael Jackson is really from, a single course of zeros will make sure the data is gone and that the drive is safe to .


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Posted at 11:22am PKST  Comments(102) |

Wednesday 3rd September 2008

Start of Ramadan fasting


As of yesterday, the Islamic month of Ramadan has started in Pakistan (there is a difference of a couple of days for the sighting of the new moon in different regions) which marks the start of a month of prayers and fasting. Best wishes to all in this blessed month.

Things tend to slow down a lot in this month so I hope everyone gets the most out of it. It does change the normal routine entirely, though it is more or less up to us to decide if the change will be a positive one or a negative one. Those in need of weight loss should be more careful since fasting can actually put weight on some people instead of removing it (though I have yet to see anyone fall sick due to it).


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Posted at 14:35pm PKST  Comments(6) |

Monday 1st September 2008

Pakistan Daylight Savings Time extended

Pakistan Linux

Daylight savings time in Pakistan, which was initially planned to be in effect till the 31st of August, has been extended for another two months. This means that the clocks will now be reverted back an hour on the 1st of November instead of the 1st of September.

DST hasn't resulted in any noticeable lowering of the overall power consumption (research shows this isn't a significant benefit), but it has had a positive effect on a number of things. It left ample time for outdoor activities after office hours. The extra daylight made it easier to fit in more business meetings and attend various events.

Overall, I've loved the idea of daylight savings time and am happy that it has been extended. However, it has caused some issues with computer systems and gadgets that weren't prepared for it (thankfully, nothing as disastrous as the Y2K bug, which as we all know, wiped out most of humanity ;) ).

There is an ongoing discussion about this on the Telecom Grid Pakistan and has some good suggestions. For Microsoft systems, this link has details on how to deal with the latest change (thanks to Danish for the link).

Earlier, I blogged about updating Ubuntu Linux for DST. This time, I have done it manually by editing the same asia file before running zic. On line 1526, change the end date for Pakistan/2008 from "Sep 1" to "Nov 1" and then run zic asia. To make the change live, copy the correct zone file to /etc/localtime:

cp /usr/share/zoneinfo/Asia/Karachi /etc/localtime

This update should be available soon for most distros in their respective updates, but this is a quick fix solution that you can use until that happens.

Enjoy another 2 months of extra daylight.


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Posted at 19:15pm PKST  Comments(108) |

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