Bits and Bytes

Learn to Live

Security Protection Virus — August 2, 2011

Security Protection Virus

Just had an experience with this stupid virus called Security Protection which installs itself automatically as an antivirus and then start scanning and show fake results. Had a real annoying experience with it but after almost 20 hrs finally successfully removed it.

Thanks to the following site.




suPHP — March 17, 2011


suPHP is a tool for executing PHP scripts with the permissions of their owners.

It consists of an Apache module (mod_suphp) and a setuid root binary (suphp) that is called by the Apache module to change the uid of the process executing the PHP interpreter.

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Google’s Cloud Connect to save MS Office work automatically — March 13, 2011

Google’s Cloud Connect to save MS Office work automatically

Google Appliance as shown at RSA Expo 2008 in ...
Image via Wikipedia

NEW DELHI: Each time you open a new Word file in Microsoft Word, from now on, there won’t be any need to save your work every few seconds, for fear of losing all your data with a power cut or a computer hang. Google’s newly launched Cloud Connect toolbar for Microsoft apps, sits inside a MS Word, Excel, or Powerpoint application.

Available for free download, the toolbar enables users to directly save their MS Office work into Google’s server farms located all over the world, from any device. Google’s strategy to embed its apps inside MS Office suite, which forms almost a third of its $62 billion annual sales will be a direct hit into Microsoft’s prime bread source after Windows, if successful.

Once logged in to a Google account, the toolbar automatically keeps saving any document being currently worked upon on to a Google server farm. The catch is that your PC should once in a while be connected to the internet, to get it synced with the cloud.

“We will keep documents on the cloud till eternity for a user, as long as his or her Google account is active,” Shan Sinha, Product Manager, Google Apps told ET from Google’s Mountain View headquarters. Won’t saving a large amount of private documents of users, create legal issues for Google? “All documents are stored in an encrypted fashion, and only people with the document’s weblink would be allowed to view or edit,” he says.

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CAPTCHA — February 14, 2011
8051 Microcontroller — January 28, 2011

8051 Microcontroller

What is microcontroller?

A microcontroller (sometimes abbreviated µC, uC or MCU) is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM. Microcontrollers are designed for embedded applications, in contrast to the microprocessors used in personal computers or other general purpose applications.

Intel MCS-51 or 8051

The Intel MCS-51 is a Harvard architecture, single chip microcontroller (µC) series which was developed by Intel in 1980 for use in embedded systems.

Overview of the 8051

  • Made by Intel in 1981
  • An 8-bit, single-chip microcontroller optimized for control applications
  • 128 bytes RAM, 4096 bytes (4KB) ROM, 2 timers, 1 serial port, 4 I/O ports
  • 40 pins in a dual in-line package (DIP) layout

General Physical Features

  • 4KB ROM

  • 128 bytes internal RA

  • 4 register banks of 8 bytes each (R0-R7)

  • 16 bytes of bit-addressable area

  • 80 bytes of general purpose memory

  • Four 8-bit I/O ports (P0-P3)

  • Two 16-bit timers (Timer0 & Timer1)

  • One serial receiver-transmitter interface

  • Five interrupt sources (2 external & 3 internal)

  • One oscillator (generates clock signal)

The 8051 Block Diagram


The 8051 Pin Assignments

Pinout Description

Pins 1-8: Port 1 Each of these pins can be configured as an input or an output.

Pin 9: RST A logic one on this pin disables the microcontroller and clears the contents of most registers. In other words, the positive voltage on this pin resets the microcontroller. By applying logic zero to this pin, the program starts execution from the beginning.

Pins10-17: Port 3 Similar to port 1, each of these pins can serve as general input or output. Besides, all of them have alternative functions:

Pin 10: RXD Serial asynchronous communication input or Serial synchronous communication output.

Pin 11: TXD Serial asynchronous communication output or Serial synchronous communication clock output.

Pin 12: INT0 Interrupt 0 input.

Pin 13: INT1 Interrupt 1 input.

Pin 14: T0 Counter 0 clock input.

Pin 15: T1 Counter 1 clock input.

Pin 16: WR Write to external (additional) RAM.

Pin 17: RD Read from external RAM.

Pin 18, 19: X2, X1 Internal oscillator input and output. A quartz crystal which specifies operating frequency is usually connected to these pins. Instead of it, miniature ceramics resonators can also be used for frequency stability. Later versions of microcontrollers operate at a frequency of 0 Hz up to over 50 Hz.

Pin 20: GND Ground.

Pin 21-28: Port 2 If there is no intention to use external memory then these port pins are configured as general inputs/outputs. In case external memory is used, the higher address byte, i.e. addresses A8-A15 will appear on this port. Even though memory with capacity of 64Kb is not used, which means that not all eight port bits are used for its addressing, the rest of them are not available as inputs/outputs.

Pin 29: PSEN If external ROM is used for storing program then a logic zero (0) appears on it every time the microcontroller reads a byte from memory.

Pin 30: ALE Prior to reading from external memory, the microcontroller puts the lower address byte (A0-A7) on P0 and activates the ALE output. After receiving signal from the ALE pin, the external register (usually 74HCT373 or 74HCT375 add-on chip) memorizes the state of P0 and uses it as a memory chip address. Immediately after that, the ALU pin is returned its previous logic state and P0 is now used as a Data Bus. As seen, port data multiplexing is performed by means of only one additional (and cheap) integrated circuit. In other words, this port is used for both data and address transmission.

Pin 31: EA By applying logic zero to this pin, P2 and P3 are used for data and address transmission with no regard to whether there is internal memory or not. It means that even there is a program written to the microcontroller, it will not be executed. Instead, the program written to external ROM will be executed. By applying logic one to the EA pin, the microcontroller will use both memories, first internal then external (if exists).

Pin 32-39: Port 0 Similar to P2, if external memory is not used, these pins can be used as general inputs/outputs. Otherwise, P0 is configured as address output (A0-A7) when the ALE pin is driven high (1) or as data output (Data Bus) when the ALE pin is driven low (0).

Pin 40: VCC +5V power supply.

New Software allows you to control computer commands by thought — January 8, 2011

New Software allows you to control computer commands by thought

Interface neuronale
Image via Wikipedia

MUMBAI: A new software platform, developed by French scientists , which was demonstrated at a tech fest at the Indian Institute of Technology (IIT) here allows individuals to control computer commands by just a ‘thought’.

Acting as an interface designed to translate what happens in the brain into a computer command, this software –‘OpenViBE‘– is the outcome of a project initiated in 2005 and has a multitude of potential applications.

“The OpenViBE software platform facilitates the design, testing and use of ‘brain-computer interfaces‘ – in other words, systems that process the electrical signals linked with brain activity and translate them into a command that can be understood by machines,” computer scientists Yann Renard and Laurent Bonnet said while demonstrating the software at the Department of Computer Sciences, IIT , here yesterday


The IMEI (International Mobile Equipment Identity) number — December 22, 2010

The IMEI (International Mobile Equipment Identity) number

Example of an IMEI
Image via Wikipedia

What is IMEI number of your mobile phone ?

The IMEI (International Mobile Equipment Identity) number of a mobile phone is a 15 digit number unique to a mobile handset. Just key in *#06# on your mobile phone and it will display its IMEI number in most phones. Note it down safely. It is also usually printed on the compliance plate of the handset usually under the battery.