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Showing posts from May, 2016

How do Virtual Machine Snapshots work in VMware

When you read the word snapshot what is the first thing that comes to your mind is , "A Photograph which preserves the best moments of your life". Technically snapshot is very much the same with the difference that it preserves the state of some digital resource. In VMware a disk "snapshot" is a copy of the VM's disk file (.vmdk) captured at a certain point in time. This snapshot preserves the disk file system and the files stored on it which can be of any type (including all the operating system files). So if something goes wrong with your virtual machine, you can restore it to a snapshot which was working previously.

One can also create snapshots for different versions/service-packs on an OS.
Hence snapshots can also be looked upon as version controlling mechanism at OS level. So if your computer was shut down abruptly or gets infected by virus, just revert to a snapshot.

So how do snapshots really work ? There's just one Thumb Rule to VMware's snaps…

12 Rules of Success by Steve Jobs

Steven Paul "Steve" Jobs (February 24, 1955 – October 5, 2011) was an American information technology entrepreneur and inventor. He was the co-founder, chairman, and chief executive officer (CEO) of Apple Inc.


























More about him: https://en.wikipedia.org/wiki/Steve_Jobs

Securely upload files to a Remote Server using JAVA client code - Part 1

You would fire a HTTP or HTTPS request to a Remote Server (HTTP) to send data. Sending JSON data / XML data is different than sending file data.
A HTTP multipart request is a HTTP request that HTTP clients construct to send files and data over to a HTTP Server. It is commonly used by browsers and HTTP clients to upload files to the server.

Let me explain how a browser encodes an html form before sending to server.

When you a select a file to be uploaded via a browser, it creates a multipart (Multiple Parts) request which consists of file content and other supporting information like filesize, boundary string, content type, additional parameters etc. Instead of URL encoding the form parameters, the form parameters (including the file data) are sent as sections in a multipart document in the body of the request.

Here's what a Multipart Request looks like (Firebug View):



Transfer-Encoding chunked:
Chunked transfer encoding is a data transfer mechanism in which data is sent in a serie…