Virtualization

Virtualisation is the creation of virtual instances of computers or operating systems on a single physical machine. These virtual instances are commonly known as Virtual Machines or “VMs”. Virtual Machines share the resources of that single computer across multiple environments. Different virtual machines can run different operating systems and multiple applications on the same physical computer.

How Does Virtualization Work

• Virtualization uses software called a hypervisor such as VMware ESX Server or Microsoft Hyper-V to “virtualize” the hardware resources of an x86-based computer—including the CPU, RAM, hard disk and network controller—to create a fully functional virtual machine that can run its own operating system and applications just like a “real”, physical computer.
  
• Each virtual machine contains a complete system(BIOS, CPU, RAM, Hard Disks, Network Cards) eliminating potential conflicts.
  
• Virtualization works by inserting a thin layer of software directly on the computer hardware or on a host operating system. This contains a virtual machine monitor or hypervisor that allocates hardware resources dynamically and transparently.
  
• Multiple operating systems run concurrently on a single physical computer and share hardware resources with each other.
• By encapsulating an entire machine, including CPU, memory, operating system, and network devices, a virtual machine is completely compatible with all standard x86 operating systems, applications, and device drivers.

Hypervisor

A hypervisor is hardware virtualization software that allows multiple virtual machine to run on a single physical computer. A hypervisor is also called virtual machine monitor or "VMM".

Types of Hypervisors

There are two types of hypervisors, Hypervisor Type 1 (native, bare-metal) and Hypervisor Type 2 (hosted).

• A Type 1 (or native, bare-metal) hypervisor is a thin layer of software that runs directly on the physical host's hardware. It manages physical resources and also the interaction between the physical hardware and virtual machines. It is also responsible for monitoring the guest operating systems inside the virtual machines. A guest operating system (such as Microsoft Windows Server 2003 or Microsoft Windows XP Professional) thus runs on another level, above the hypervisor. This is the classic implementaion of virtual architectures. Examples of type 1of hypervisors are:
  • VMware ESX Server
  • Oracle VM
  • Microsoft Hyper-V
  • Xen
  • Citrix XenServer

• A Type 2 (or hosted) hypervisor is a software application that runs withing a conventional operating system environment. Considering the hypervisor layer being a distinct software layer, guest operating systems thus run at the third level above the hardware. Examples of Tye 2 hypervisors are:
  • VMware Server (formerly known as GSX)
  • VMware Workstation
  • Vmware Fusion
  • Microsoft Virtual PC
  • Microsoft Virtual Server
  • Sun xVM VirtualBox
    

Java learning paths

- Sun Certified Java Associate (SCJA)
- Sun Certified Java Programmer (SCJP) : I'm here
- Sun Certified Java Developer (SCJD)
- Sun Certified Web Component Developer (SCWCD)
- Sun Certified Business Component Developer (SCBCD)
- Sun Certified Developer For Java Web Services (SCDJWS)
- Sun Certified Mobile Application Developer (SCMAD)
- Sun Certified Enterprise Architect (SCEA)

https://www.suntrainingcatalogue.com/eduserv/client/learningPath.do?p=/training/certification/java/index.html

Google's GDrive

Taking cloud computing to a new level, Google is soon going to launch 'GDrive', a long-rumored online storage for its users.

GDrive would work as an online hard disk and could essentially work as a syncing device that will periodically update itself with the activities that take place on a computer, the Google Operating System has discovered.

Also discovered in a Google Apps CSS file is that there is reportedly an update for Google Docs on the way that would include a desktop client for syncing files with GDrive.

Since this drive will allow users to save their data online, users will be able to access their data from any computer in the world, as long as it is connected to an internet connection.

In fact, if you take Google provisions seriously, you've probably already shifted your photograph and document base to atleast one of the Google services that work as great archiving hubs. However, space restriction and reliability could be a user's concern while depending on the Google servers to save their precious data.

The GDrive could also partially replace the physical hard disk that a user needs to select an operating system (OS) for usage -- that is, after the initial booting. Google's online hard drive will merge all of Google's web based applications and make them available together.

The GDrive is expected to be launched in 2009.