History

History

• IBM announced its first official VM product, VM/370, on August 2, 1972 for the System/370. Virtualization was provided by the IBM VM operating system. IBM  VM/370 divided a mainframe into multiple virtual machines, each running its own operating system.

• Disk system were issued with the VM technique. Assume the actual machine only el has three disk drives but has to host eight virtual machines. It was obvious that it could not allocate a hard drive to each virtual computer. The solution was to create virtual disks, which were referred to as a minidisks in IBM VM OS.

• Except for size, the minidisks were identified to the systems hard disks. The system implemented each minidisk by allocating as many tracks on the physical disks as the minidisk needed.

• VM/370 is an operating system that gives multiple users access to a computer by means of keyboard and display terminals for time sharing, system testing, production and conversion. VM/370 manages the resources of a computer so that every user, local or remote, appears to have a complete replica of a System 370 including input output (I/O) devices.

• Each user of VM/370 can select a different operating system, if desired, because different operating I systems can run concurrently in different virtual machines.

Benefits and Features

• Virtual machines help organizations reduce unnecessary hardware machines such

• Flexibility Virtual machines enable organizations to run multiple operating systems simultaneously.

• Easy to backup and clone.

• Major advantage of virtual machines in production data-center use is system consolidation, which involves taking two or more separate systems and running them in virtual machines on one system.

• Saves space, time and management costs

• Support for legacy applications

• Simplify reduce downtime.