Understanding NxTop Center and NxTop Engine

The NxTop solution uses two main components to provide end-to-end virtualization: NxTop Engine and NxTop Center.

• NxTop Engine runs on each (end-user's) computer and runs NxTop images. It includes a bare-metal hypervisor, allowing the virtual machines to operate the computer's hardware. It does not require an operating system on the computer.
• NxTop Center runs on a separate server, providing the administration to support each NxTop Engine. One NxTop Center can administer many NxTop Engines and computers.

The image above describes the process in a nutshell. The following sections provide more details.

NxTop Engine

NxTop Engine is installed on individual computers, and provides a virtual platform to run each NxTop image. A NxTop image contains a virtual machine (VM) of an operating system plus any included applications.

A NxTop Engine may have more than one NxTop image on a computer. The NxTop image definition includes its RAM and storage requirements. Managing the memory use is performed by the NxTop Engine.

More than one NxTop can be running at once, and the user can switch between NxTop images, or between an image at the NxTop Engine in a single key press.

NxTop Engine also performs the security and management tasks on the computer:

• Checks that the user password is correct (otherwise no access to the computer)
• Provides disk encryption services
• Establishes network connections (wireless and/or wired)
• Communicates securely (through SSL) with NxTop Center and checks for updated NxTops, changes to Policies or Virtual Applications. Policies can require that the user contacts NxTop Center, or the user can be locked out of a NxTop image
• Downloads and prepares new versions of NxTop as a background task
• Uploads (and tracks) backups to NxTop Center
• Maintains local backup

While the NxTop Engine does communicate securely with NxTop Center, that communication is not a requirement for operating. The NxTop Engine runs independently on an individual computer to run one or more loaded NxTop image.

NxTop Center

NxTop Center performs all the administrative tasks for the solution.

It keeps a database of all objects in the NxTop solution:

• Users: which computer is assigned to each, which NxTops, Policies, and Virtual Applications are assigned, the backups for each NxTop
• Groups: which users belong to which groups, and group assignments
• NxTops: which OS, and version, which Groups and Users, policies, and virtual applications are assigned
• Policies: policy definitions for Expiration, Backup, Lockout, USB device use
• Software: what is available in the Software library, and to which NxTops has it been assigned
• Computers: which users are supposed to use them
• Events: detailed audit trail of actions for each object in NxTop Center

NxTop Center builds the NxTops, manages local users and groups, handles integration with Active Directory, and assigns NxTops to users. When contacted by a NxTop Engine, it sends down (updated NxTops, virtual applications, or policies, and restored user data) or accepts (backups) appropriate files and holds them as needed.

NxTop Center can restore a user's data from backup onto the same or a new computer. NxTop center itself can be backed up and restored using conventional backup tools.

The Administrator can request information about the computer running a NxTop - disk use, hardware available, diagnostics. The Administrator can create a copy of a NxTop in a Workbench equipped with tools to examine and optimize the NxTop.

Description of Basic Operations

The following section describes the operation of a typical NxTop session.

1. User turns on computer, starting NxTop Engine.
2. User logs in. NxTop Engine checks credentials and (if accepted) opens NxTop Launcher screen on computer.
3. If connected (by wire or wireless), NxTop Engine checks with NxTop Center for changes to application or policy assignments, or the presence of an updated NxTop. If it finds them, it begins any download as a background task.

   Once downloaded, the NxTop Engine will update the NxTop image, and then use the updated version next time that image is started.

4. User chooses which NxTop to run. If there is only one NxTop on the computer, the NxTop Engine can be configured to start automatically. The OS boots up as if it was natively installed.
5. The User uses computer normally, switching between NxTops if desired. The NxTop Engine tracks changes made during the user session.
6. If the NxTop is configured for automatic backup, if a backup is due while the computer is on, the NxTop Engine uploads an incremental backup file to NxTop Center, and starts a new backup file. Each NxTop on a computer is backed up individually.
7. When finished, the user shuts the NxTop down. Changes made during the user session to user data are preserved locally.
8. The user can either suspend the computer or power it down. If the user tries to power down the computer without shutting down the NxTops, the NxTop Engine first shuts down the NxTops to prevent loss of data.

   From a suspend state, the user can restart the computer by raising the cover of the laptop, without needing to wait for the NxTop Engine to restart. If battery down runs low, the NxTop Engine will shut down any open NxTops and power down the computer.