Abstract: The invention provides apparatus and systems for high availability execution of applications executing on one or more digital data processor platforms. For example, a system according to one aspect of the invention includes a first set digital data processors, each of which executes one or more applications. These are referred to as “primaries” or “primary applications.” A second set of digital data processors execute virtual machines, each of which, in turn, executes an image of a corresponding primary application. These are referred to as “imaged” or “imaged applications.” Each of the first and second sets may have one or more digital data processors. Agent functionality residing on and/or coupled to the digital data processors in the first and second sets maintains state/configuration information for each imaged application.

Abstract: The invention provides, in one aspect, a digital data processing device includes a firewall device and a computer, both housed within the same enclosure and sharing a common path to the Internet (or other external network), yet, not sharing the same substantive processing logic. Thus, by way of example, the firewall device does not the computer's central processing unit (CPU) to execute firewall logic. The digital data processing device can be arranged to limit connectivity and/or functionality of the computer and/or firewall device, e.g., absent authentication. Thus, for example, the computer and firewall can be coupled to the common path—e.g., a modem, network interface card or other communications port supporting access via wired (e.g., wired ethernet and coaxial), wireless (e.g., satellite, telephony, 802.11x), and/or optical (e.g., fiber) means—such that that access by the computer to the Internet (or other external network) is mediated by the firewall device.