Friday 30 May 2008

Popups

Recently I was working on my brother's computer, when I found the following popup from the antivirus. Evidently the real time protection worked as it came when I was working online.



The malware (I choose to refer in a generic fashion as different vendors differ on whether it is a trojan or a virus) Trojan.Clicker.CM comes from adsrevenue.net. Now, I was working in a different site and I tried a download. The download was supposed to be initiated from another window and along with that new window came the popup which was blocked by the antivirus.

Some googling yielded that http://www.adsrevenue.net/ is the website of a company that lives on ads. However, it also hints at the grim prospect that malware are used by companies to make money, that cybercrime secretly thrives on companies like this one.

Sunday 4 May 2008

Memristor

Basic electronics tells us that there are three passive components :
1. Resistor
2. Capacitor
3. Inductor.
Now the trinity has been joined by a new member - the memristor.

In 1971, an IEEE fellow and pioneer of non-linear circuit theory, Leon Chua, working as an engineer in the University of California, Berkeley, predicted that there should be a fourth element: a memory resistor, or memristor. But no one knew how to build one. Now, 37 years Hewlett-Packard researchers have finally designed one.

Earlier it was conceived only from a mathematical perspective and no real manifestation was existent. According to Chua, memristor provides a similar relationship between magnetic flux and charge that a resistor gives between voltage and current. That it acts like a resistor whose value varies according to the current passing through it and which remembers that value even after the current has disappeared. This hints at using the device as a memory resistor.

The team was lead by R. Stanley Williams. They were working on molecular electronics. The memristor is fundamental circuit element as no combination of other fundamental passive elements can make a device remember the current flowing through it earlier. The effect can be produced using transistors and capacitors but a large number of them is needed to produce the effect of a single memristor. The symbol for memristor is as follows.


Looking into the practical applications, we see that with the use of memristors we might never need to boot up again; everything that was in memory while we turned off would be in memory when we turn the system back on. Moreover, memristors are likely to help hardware based implementations of neural networks and fuzzy logic. According to Williams, computations may no more be in Boolean fashion only. Also there can be designs of non-volatile memory based on memristors that could be 1000 times faster than traditional magnetic disks yet consume quite less power.

This is an achievement of nanoscience. For those who could not welcome nanoscience due to prejudices of privacy breach by nanorobots, here is a view of how much easy nanoscience can make your lives.

Some time ago I had read a Linux kernel developer saying that we are not having enough development in hardware. Well here is one.