Sen Computing: 2015

Monday, 21 December 2015

IMEI Number

IMEI stands for 'International Mobile Equipment Identity', is a unique (15 or 17 digit) number assigned to mobile phone. It can also be found in 3G/4G tablets, laptops with PCMCIA wireless internet cards, and other mobile equipment. In a dual-SIM phone, you’ll see two IMEI numbers, one for each SIM slot. The IEMI is also known as 'International Mobile Station Equipment Identity'. In the case of CDMA network there is also a MEID number.

The main purpose of using this number is to trace the device. As the number is unique, it helps us to identify the device and therefore it can be used for stopping a phone from accessing that network if it is theft. We can use this number to block a mobile phone from being used by another person.

How to find this number:

Dial *#06# on your keypad and press call or send button, your IMEI number will be retrieved and displayed on your screen.
On the back or bottom of the device or under, IMEI number can be found printed.
IMEI numbers can also be printed on the original packaging of your device.

The Structure of an IMEI Number:
IMEI numbers either come in a 17 digit or 15 digit sequences of numbers. The IMEI format currently utilized is AA-BBBB-CC-XXXXXX-Z:

First 8 digits of IMEI number are TAC (Type Allocation Code) which will give you the mobile phone brand and model. Other 7 digits are defined by manufacturer (6 are serial number and 1 is check digit).

For example a IMEI number: 354230061155201

Here TAC: 354230 | FAC: 06 | SNR: 115520 | CD: 1

Monday, 23 November 2015

CSS

According to W3C , CSS is a simple mechanism for adding style (e.g., fonts, colors, spacing) to Web documents. The elaboration of CSS is Cascading Style Sheets. It describes how the markup language will be demonstrated in the screen.

CSS separates the document content from document presentation. This separation improves to write markup language in a clean way. Moreover, it enables to use same design style in various part of the document which reduces the redundancy of writing more style languages.

Håkon Wium Lie first proposed about CSS in 1994 when he was working with Tim Berners-Lee at CERN. Gijsbert (Bert) Bos also proposed similar type of idea at that time. W3C released first CSS Recommendation (CSS1) in 1996 after much discussion on various mailing list.

CSS have simple syntax. A CSS rule-set consists of a Selector and a Declaration Block. Selector points to the markup language (i.e HTML element) element and Declaration block contains a list of declaration in braces. Each declaration consists of property and value and separated by colon. Each declaration ends up with semicolon. Markup language elements are may be specified with attributes like Id or Class.

Example:

Suppose H1 is a HTML tag and the document can be written as:

<h1> Sen Computing </h1>

It can be associated with CSS ----

<h1 style="color: red; font-size: 15px;"> Sen Computing </h1> [Inline stylesheet]

h1{color: red; font-size:15px} [External stylesheet]

External stylesheet can be written in file that have .css extension and can be linked up with the HTML file.

The current version of CSS is CSS3.