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Showing posts from January, 2014

What is Garbage Collector Compaction in Java?

Compaction means moving objects in RAM so that objects become contiguous in RAM. There are some cases when you will get out of memory error without any memory leak . And there may be memory available but there is no place for new object because of no  contiguous availability of memory. The algorithmic difficulty in a compaction algorithm is about updating all pointers, so that they point to the new object location. GC works preferentially with young objects only. Here, this means compacting only the end of the heap. full compaction being applied  rarely.  .Lets see with an example :-

The point here is that a full compaction,  could  induce a noticeable pause. Generational GC tries to make such pauses rarer . In GC pause all threads of your application will be suspended

What is difference between Web Server and Application Server ?

Hemant
Kurmi Web Server Definition

A web server is a service that handles specifically requests in the HTTP protocol format. The server responses to requests made using the HTTP format, and in turn responds using a valid HTTP response. All responses from a web server follow the W3 standards for HTTP protocols.Web server can be either a computer program or a computer running a program that is responsible for accepting HTTP requests from clients, serving back HTTP responses along with optional data contents, which usually are web pages such as HTML documents and linked objects on it.This is mainly used for Servlets and JSP.

Or we can say Web server can be either a computer program or a computer running a program that is responsible for accepting HTTP requests from clients, serving back HTTP responses along with optional data contents, which usually are web pages such as HTML documents and linked objects on it.
The Web Server does not support the concept of multi-threading

As web servers are w…

What is the maximum ram for 32 bits and 64 bits computer?

To bet the answer lets begin with our running 32 bits computer .
As we know the maximum ram is the locations that OS can handle
and for a processor it is the register bus. so we can make a simple formula for this

2^(width of data bus in bits)
or
 2^(how much bits OS is)

So for 32 bit computer(4 bytes pointer) the maximum RAM that can be addressed will

2^32 --->> can address 4,294,967,296 locations = 4GB

So a 32 bits OS can have maximum of 4GB of ram.

Exeption 
These can be extended by hardware coding and including more "hidden" address lines.The number of these "hidden" address lines decides by how much you can extend your RAM.But its complicated

Now moving towards 64 bits OS . As said by Moore’s Law, That the number of transistors on a chip doubles every 1.5 to 2 years.
now its too easy to calculate

i.e 2^64 --->>can address 1.84467440737e+19 locations

Means
Maximum RAM  = 16*1000*1000 *1000GB
Maximum RAM = 16*1000*1000 TB
Maximum RAM = 16*1000 Petabyte=16 Exabyte

So it…

Some Amazing fact about memory (petabyte,exabyte,zettabyte) And How much data exists on the Web?

Now the Digital world is growing to fast that our need for storing data is increasing day by day. I remember once our computer teacher told that he purched a  Personal Computer XT/370 and paid more then a lakh for it and cobtainns 512K of memory chips.but Now you can you can find 64bit computers with 8 gb of ram laptops . Even mobiles come with 3 Gb ram(Note 3 of samgang)

And going towards harddisk we are no more talking about GBs now its all about Terabytes . And not we stop here we moved toward Petabyte(1000 TB). I here remember
 Moore’s Law, which says that the number of transistors on a chip doubles every 1.5 to 2 years.

Let me share on intresting fact:-

The biggest photo sharing website Facebook has over 15 billion photos. For each uploaded  photo, Facebook generates and stores four images of different sizes, which translated to a total of 60 billion images and 1.5 petabytes of storage, to date this will be even greater.

 If the average MP3 encoding for mobile is around 1MB per minute…