History of Virtualization

Virtualization was first developed in the 1960s to partition large, mainframe hardware for better hardware utilization. Today, computers based on x86 architecture are faced with the same problems of rigidity and underutilization that mainframes faced in the 1960s. VMware invented virtualization for the x86 platform in the 1990s to address underutilization and other issues, overcoming many challenges in the process. Today, VMware is the global leader in x86 virtualization, with over 170,000 customers, including 100% of the Fortune 100.

In the Beginning: Mainframe Virtualization

Virtualization was first implemented more than 30 years ago by IBM as a way to logically partition mainframe computers into separate virtual machines. These partitions allowed mainframes to “multitask”: run multiple applications and processes at the same time. Since mainframes were expensive resources at the time, they were designed for partitioning as a way to fully leverage the investment.

The Need for x86 Virtualization

Virtualization was effectively abandoned during the 1980s and 1990s when client-server applications and inexpensive x86 servers and desktops led to distributed computing. The broad adoption of Windows and the emergence of Linux as server operating systems in the 1990s established x86 servers as the industry standard. The growth in x86 server and desktop deployments led to new IT infrastructure and operational challenges. These challenges include:

• Low Infrastructure Utilization. Typical x86 server deployments achieve an average utilization of only 10% to 15% of total capacity, according to International Data Corporation (IDC), a market research firm. Organizations typically run one application per server to avoid the risk of vulnerabilities in one application affecting the availability of another application on the same server.
• Increasing Physical Infrastructure Costs. The operational costs to support growing physical infrastructure have steadily increased. Most computing infrastructure must remain operational at all times, resulting in power consumption, cooling and facilities costs that do not vary with utilization levels.
• Increasing IT Management Costs. As computing environments become more complex, the level of specialized education and experience required for infrastructure management personnel and the associated costs of such personnel have increased. Organizations spend disproportionate time and resources on manual tasks associated with server maintenance, and thus require more personnel to complete these tasks.
• Insufficient Failover and Disaster Protection. Organizations are increasingly affected by the downtime of critical server applications and inaccessibility of critical end user desktops. The threat of security attacks, natural disasters, health pandemics and terrorism has elevated the importance of business continuity planning for both desktops and servers.
• High Maintenance end-user desktops. Managing and securing enterprise desktops present numerous challenges. Controlling a distributed desktop environment and enforcing management, access and security policies without impairing users’ ability to work effectively is complex and expensive. Numerous patches and upgrades must be continually applied to desktop environments to eliminate security vulnerabilities.

The VMware Solution: Full Virtualization of x86 Hardware

In 1999, VMware introduced virtualization to x86 systems to address many of these challenges and transform x86 systems into a general purpose, shared hardware infrastructure that offers full isolation, mobility and operating system choice for application environments.

Challenges & Obstacles to x86 Virtualization

Unlike mainframes, x86 machines were not designed to support full virtualization, and VMware had to overcome formidable challenges to create virtual machines out of x86 computers.

The basic function of most CPUs, both in mainframes and in PCs, is to execute a sequence of stored instructions (ie, a software program). In x86 processors, there are 17 specific instructions that create problems when virtualized, causing the operating system to display a warning, terminate the application, or simply crash altogether. As a result, these 17 instructions were a significant obstacle to the initial implementation of virtualization on x86 computers.

To handle the problematic instructions in the x86 architecture, VMware developed an adaptive virtualization technique that “traps” these instructions as they are generated and converts them into safe instructions that can be virtualized, while allowing all other instructions to be executed without intervention. The result is a high-performance virtual machine that matches the host hardware and maintains total software compatibility. VMware pioneered this technique and is today the undisputed leader in virtualization technology.