초록 ▼

A computer system and method are provided for executing multiple software of different mission-criticality. The computer system includes at least one access control circuit to prevent access to memory assigned to software of greater mission-criticality by software of lesser mission-criticality. The

A computer system and method are provided for executing multiple software of different mission-criticality. The computer system includes at least one access control circuit to prevent access to memory assigned to software of greater mission-criticality by software of lesser mission-criticality. The access control circuit is configured to be in a first position allowing access to a first memory for purposes of data retrieval and storage when the greater mission-critical software is executing and in a second position when a lesser mission-critical software is executing, allowing access to a second memory but preventing access to the first memory. The greater mission-critical software is configured to provide control signals to the access control circuit instructing the access control circuit to maneuver to the second position, when necessary, by generating an interrupt.

대표청구항 ▼

1. A computer system comprising:a storage means for storing at least a first software having a first mission-criticality and a second software having a second mission-criticality, wherein said first mission-criticality is greater than the second mission-criticality, an input/output arrangement for p

1. A computer system comprising:a storage means for storing at least a first software having a first mission-criticality and a second software having a second mission-criticality, wherein said first mission-criticality is greater than the second mission-criticality, an input/output arrangement for providing data input output functionality; and means for executing the first and second software using a single processor, wherein said means for executing is connected to said storage means and said input/output arrangement, such that when executing said first software, input data is fetched from a first memory connected to said storage means and output data is stored to said first memory and when executing said second software, input data is fetched from a second memory connected to said storage means and output data is stored to said second memory, whereas said second software is prevented from affecting data stored in the first memory, and wherein said first software controls which output data is transferred from the first memory and the second memory to said data input/output arrangement thereby preventing output, via said input/output arrangement, of data from said second software which has not been checked by said first software. 2. A computer system according to claim 1, further comprising an access control means connected to the means for executing for controlling access to data in the first memory, whereas said access control means is adapted to be in a first position when executing the first software so that access to data in the first memory is enabled for the first software, and in a second position when executing the second software so that access to data in the first memory is disabled for the second software.3. A computer system according to claim 2, wherein said access control means is further adapted to control access to other computer system components included in the computer system in a manner that access to said components is enabled when said access control means is in the first position but disabled when said access control means is in the second position.4. A computer system according to claim 2, wherein said access control means is further adapted to be maneuverable into its first position by means of an interrupt generated in the computer system.5. A computer system according to claim 4, wherein said interrupt is a Non-Maskable Interrupt (NMI).6. A computer system according to claim 2, wherein said access control means is adapted to be maneuverable into its second position by means of the first software.7. A computer system according to claim 2, wherein said access control means comprises at least one logic circuit.8. A computer system according to claim 1, wherein said first software is adapted to be activateable by means of an interrupt generated in the computer system.9. A computer system according to claim 8, wherein said interrupt a Non-Maskable Interrupt (NMI).10. A computer system according to claim 1, wherein said second software is adapted to be activateable by means of the first software.11. A computer system according to claim 1, wherein said first memory is a Random Access Memory (RAM).12. A computer system according claim 1, wherein said second memory is a Random Access Memory (RAM).13. A computer system according to claim 1, wherein said storage means is a Programmable Read Only Memory (PROM).14. A method for executing software of different mission-criticality, comprising the steps of:providing a first software; providing a second software having a lower mission-criticality than said first software; and executing said first software and said second software by a single processor, wherein when executing said first software, input data is fetched from a first memory and output data is stored to said first memory and when executing said second software, input data is fetched from a second memory and output data is stored to said second memory, wherein said second software is prevented from affecting data stored in the first memory, and wherein said first software controls which output data is transferred from the first memory and the second memory to a data input/output arrangement thereby preventing output, via said input/output arrangement, of data from said second software which has not been checked by said first software. 15. A method according to claim 14, further comprising the step of controlling access to said data, performed by at least one logic circuit, wherein said at least one logic circuit is adapted to be in a first position when executing said first software so that access to data in said first memory is enabled for said first software, and in a second position when executing said second software so that access to data in said first memory is disabled for said second software.16. A method according to claim 15, wherein said at least one logic circuit is adapted to be maneuverable into its second position by execution of the first software, said first software being activateable by means of an interrupt generated in the computer system and configured to activate said second software.17. A method according to claim 16, wherein said interrupt is a Non-Maskable Interrupt (NML).18. A computer system comprising:a storage means for storing at least a first software having a first mission-criticality and a second software having a second mission-criticality, wherein said first mission-criticality is greater than said second mission-criticality; an input/output arrangement for providing data input and output functionality; means for executing the first and second software using a single processor, wherein said means for executing is connected to said storage means and said input/output arrangement, wherein when executing said first software, input data is fetched from a first memory an output data is stored to said first memory and when executing said second software, input data is fetched from a second memory and output data is stored to said second memory, wherein said second software is prevented from affecting data stored in the first memory, and wherein said first software controls which output data is transferred from the first memory and the second memory to said input/output arrangement thereby preventing output, via said input/output arrangement, of data from said second software which has not been checked by said first software; and an access control means for controlling access to data in the first memory, wherein said access control means is connected to said means for executing and adapted to be in a first position when executing the first software so that access to data in the first memory is enabled for the first software, and in second position when executing the second software so that access to data in the first memory is disabled for the second software. 19. A computer system according to claim 18, wherein said access control means is further adapted to control access to other computer system components included in the computer wherein access to said components is enabled when said access control means is in the first position and disabled when said access control means is in the second position.20. A computer system according to claim 18, wherein said access control means is further adapted to be maneuverable into its first position by means of an interrupt generated in the computer system, said interrupt is a Non-Maskable interrupt (NMI).21. A computer system according to claim 18, wherein said access control means is comprised of at least one logic circuit adapted to be maneuverable into its second position by execution of the first software, said first software being activateable by means of an interrupt generated in the computer system and configured to activate said second software.