Abstract: A computer or other electronic device may be used in one of several selectable modes of operation. Computer resources, such as a processor, memory, or a graphics controller, are individually settable for operation at different levels of performance. A mode of operation or performance level is determined by the combination of individual settings for the various resources. Pay-per-use operation is charged at a rate determined by the mode of operation or performance level. Operation in a gaming mode may be charged at a higher rate than operation in web-browsing mode. A metering agent may be associated with each scalable use resource to securely set the performance level and to securely report on metered operation of the resource.

Abstract: An SPI switch allows selection of a BIOS memory transparent to a Southbridge chipset component. The SPI switch provides address translation to a selected BIOS memory area under the control of a security module processor. The SPI switch also provides command filtering to prevent commands that represent a security risk such as bulk erase commands. Because the SPI switch allows transparent redirection between BIOS programs, booting in different operating modes may be supported without any changes to the basic computer architecture or major chipset components.

Abstract: A display device for use with a computer adapted for operation in an unrestricted use mode and a limited function mode and a method for enforcing a limited function mode display is disclosed. The display device enters a limited function mode when a condition of non-compliance with an operating policy is discovered by the computer. Additionally, the display device may also enter a limited function mode upon powering up or when connections to the computer and/or selected components of the display are disabled or disconnected. When in the limited function mode, the display may support a limited function interface for use in correcting the condition of non-compliance.

Abstract: A virtual machine monitor provides a trusted operating environment for a software usage metering application when a qualified virtual machine monitor is loaded as part of trusted boot and when all other programs and operating systems run in containers managed by the virtual machine monitor. The virtual machine monitor may also host a locking application for limiting the functionality of the computer if contractual terms of use are not met. Both the metering and locking applications run at a higher privilege level than ring 0, at the same level as the virtual machine monitor.

Abstract: A computer that self-administers operating in restricted and unrestricted operating modes boots from a main processor and operates normally in the unrestricted operating mode and operates from an alternate processor in a security module in the restricted operating mode. The alternate processor may communicate directly with peripheral devices such as a display controller and keyboard. Because the main processor is not used and may not even be started in the restricted operating mode, viruses, shims, and other related attacks are virtually eliminated. In one embodiment, the security module may operate as a PCI bus master when in the restricted operating mode.

Abstract: A computer that operates in a metered mode for normal use and a restricted mode uses an input/output memory management unit (I/O MMU) in conjunction with a security policy to determine which peripheral devices are allowed direct memory access during the restricted mode of operation. During restricted mode operation, non-authorized peripheral devices are removed from virtual address page tables or given vectors to non-functioning memory areas.

Abstract: A security circuit in a computer monitors data busses that support memory capable of booting the computer during the computer reset/boot cycle. When activity oil one of the data busses indicates the computer is booting from a non-authorized memory location, the security circuit disrupts the computer, for example, by causing a reset. Execution from the non-authorized memory location may occur when an initial jump address at a known location, such as the top of memory, is re-programmed to a memory location having a rogue BIOS program.

Abstract: A computer or other electronic device requiring physical integrity of its components, for example, a pay-per-use computer may use a master security device in communication with a plurality of slave security devices, known as security beans. Each security bean may be given a cryptographic key or keys for use in authenticating communication with the master security device. Each security bean may be coupled to an associated component and may have the ability to disable that associated component. In one embodiment, security bean has an analog switch that may be configured to block or attenuate a critical signal used by the associated component. The security bean may start up in the disable mode and respond to a verified signal from the master security device to enable its corresponding component.

Abstract: A computer or electronic device uses a dedicated communication protocol for configuring, managing, and end-of-life operation of a master device controlling a plurality of security devices. The protocol includes messages for binding each security device to the master, for installing cryptographic keys, periodic heartbeat signals, as well as shutdown and disable-security messages.

Abstract: A security module for a pay-per-use computer supplies an appropriate BIOS for a given mode of operation. A power manager in the security module powers only essential circuits until the BIOS is operational to help prevent substitution of a non-authorized BIOS. The security module also includes a capability to monitor and restrict data lines on a bus between a main computer processor and computer system memory. When the computer is operating in a restricted use mode, data lines may be restricted to allow only minimal access to the computer system memory. Bus transactions may be monitored to ensure that only valid transactions are occurring and are within the designated memory space.

Abstract: A computer is configured for either full operation with metering or limited mode operation. When in limited mode operation, the system memory may be partitioned into active and restricted memory. The active memory may be limited to an amount needed to execute a limited mode operation application. The remaining restricted memory may be made inaccessible to the computer's processor. To verify the restricted memory remains unused, it may be filled with a pattern and the pattern periodically verified to determine that unauthorized programs are not using the restricted memory.

Abstract: An evaporative emissions control system for small internal combustion engines, including a charcoal canister which is in fluid communication with the air space above the liquid fuel within the carburetor of the engine and the air space above the liquid fuel within the fuel tank of the engine. The charcoal canister contains charcoal media, and when the engine is not running, fuel vapors from the carburetor and the fuel tank migrate to, and are trapped within, the charcoal media of the charcoal canister. The charcoal canister may comprise a separate component, or may be integrally formed with an engine component such as the air cleaner, the carburetor, or the body of the fuel tank, for example. During running of the engine, vacuum within the carburetor induces a flow of atmospheric air through the charcoal canister to purge the collected fuel vapors from the charcoal media, and the fuel vapors pass into the engine for consumption.

Abstract: An evaporative emissions control system for small internal combustion engines. The system generally includes a charcoal canister and a carburetor with a fuel circuit shutoff valve. The charcoal canister is in fluid communication with the air space above the liquid fuel within the engine fuel tank, and optionally, with the air space above the liquid fuel within the fuel bowl of a fuel bowl-type carburetor. The charcoal canister contains charcoal media which absorbs fuel vapors when the engine is not running. During running of the engine, vacuum within the carburetor induces a flow of atmospheric air through the charcoal canister to purge the collected fuel vapors from the charcoal media, and the fuel vapors pass into the engine for consumption. The carburetor of the engine, which may be either a fuel bowl-type carburetor or a diaphragm carburetor, includes a fuel circuit shutoff valve controlled either by a vacuum signal produced within the engine or by a user-actuated mechanical linkage.

Abstract: An automatic priming system for internal combustion engines, which is operable at engine cranking speeds and which is automatically disabled at engine running speeds. The automatic priming system is driven by pressure fluctuations within the engine crankcase which are caused by reciprocation of the piston. At engine cranking speeds, fluid communication between the engine crankcase and a chamber is substantially equalized, such that positive pressure pulses from the crankcase air space pass from the chamber through a check valve to the carburetor for priming. At engine running speeds, communication between the crankcase air space and the chamber is restricted such that the pressure within the chamber is below atmospheric, positive pressure pulses are not present within the chamber, and the priming function is automatically disabled.

Abstract: Piston stroke recognition methods for small internal combustion engines, such as single and two cylinder engines, in which the ignition-related trigger pulses corresponding to the engine cylinders are the only input signal used for stroke recognition.

Abstract: An automatic priming system for internal combustion engines, which is operable at engine cranking speeds and which is automatically disabled at engine running speeds. The automatic priming system is driven by pressure fluctuations within the engine crankcase which are caused by reciprocation of the piston. At engine cranking speeds, fluid communication between the engine crankcase and a chamber is substantially equalized, such that positive pressure pulses from the crankcase air space pass from the chamber through a check valve to the carburetor for priming. At engine running speeds, communication between the crankcase air space and the chamber is restricted such that the pressure within the chamber is below atmospheric, positive pressure pulses are not present within the chamber, and the priming function is automatically disabled.

Abstract: A valve clearance adjustment mechanism for use in small internal combustion engines such as, for example, side valve engines and overhead valve engines, which generally include intake and exhaust valves actuated by lifters pivotally mounted within the engine housing, which in turn are actuated by cam lobes driven in timed rotation with the crank shaft. An adjustment member is provided for mounting each lifter to a shaft, wherein the adjustment member is eccentric relative to the shaft, such that rotation of the adjustment member modifies the position of the lifter and in turn modifies the valve clearance between the lifter and the valve. After the valve clearance has been properly set, the adjustment member is fixed in position.

Abstract: A valve clearance adjustment mechanism for use in small internal combustion engines such as, for example, side valve engines and overhead valve engines, which generally include intake and exhaust valves actuated by lifters pivotally mounted within the engine housing, which in turn are actuated by cam lobes driven in timed rotation with the crank shaft. An adjustment member is provided for mounting each lifter to a shaft, wherein the adjustment member is eccentric relative to the shaft, such that rotation of the adjustment member modifies the position of the lifter and in turn modifies the valve clearance between the lifter and the valve. After the valve clearance has been properly set, the adjustment member is fixed in position.

Abstract: The present invention involves a carbureted fuel system for an internal combustion engine for small utility implements. The engine includes a crankcase with a cylinder bore. The crankcase rotatably supports a crankshaft having a flywheel and a magnet disposed on an outer periphery of the flywheel. The crankshaft is also connected to a reciprocating piston disposed in the cylinder bore. A cylinder head is attached to the crankcase over the cylinder bore, and a carburetor is disposed on the cylinder head. The carburetor is in communication with a fuel supply and an air inlet. The carburetor includes a mixing chamber in which the fuel and air are mixed together and then introduced into the manifold and eventually into the cylinder via a valve for combustion therein. In communication with the main passage of the carburetor is a secondary air inlet in which is disposed an air bleed device, such as a solenoid or PZT operated actuator, which is controlled by an electronic control unit.

Abstract: The present invention involves a carbureted fuel system for an internal combustion engine for small utility implements. The engine includes a crankcase with a cylinder bore. The crankcase rotatably supports a crankshaft having a flywheel and a magnet disposed on an outer periphery of the flywheel. The crankshaft is also connected to a reciprocating piston disposed in the cylinder bore. A cylinder head is attached to the crankcase over the cylinder bore, and a carburetor is disposed on the cylinder head. The carburetor is in communication with a fuel supply and an air inlet. The carburetor includes a mixing chamber in which the fuel and air are mixed together and then introduced into the manifold and eventually into the cylinder via a valve for combustion therein. In communication with the main passage of the carburetor is a secondary air inlet in which is disposed an air bleed device, such as a solenoid or PZT operated actuator, which is controlled by an electronic control unit.