Memory management and protection system for virtual memory in computer system

A memory management system for converting a logical address into a physical address in a computer which executes a plurality of programs allocated to a virtual space in parallel by activating a plurality of threads, comprising:

• access permission memory means for storing access permissions indicating whether each thread is permitted to make accesses to the logical address;
• a thread number memory for storing a thread number assigned to a currently executing thread which is currently executing the programs;
• verification means for verifying whether the currently executing thread specified by the thread number stored in the thread number memory is permitted to make accesses to the logical address, according to the access permissions stored in the access permission memory means;
• and
• means for outputting the physical address converted from the logical address when the verification means verifies that the currently executing thread is permitted to make accesses to the logical address.

A memory management system for converting a logical address into a physical address in a computer which executes programs allocated to a virtual space divided into a plurality of address regions, comprising:

• access permission memory means for storing access permissions indicating whether accesses from each program allocated to each address region to the logical address are permitted;
• address region detection deans for detecting a current address region containing a currently executing program which makes an access to the logical address;
• verification means for verifying whether accesses from the current address region detected by the address region detection means to the logical address are permitted, according to the access permissions stored in the access permission memory means;
• and
• means for outputting the physical address converted from the logical address when the verification means verifies that the accesses from the current address region to the logical address are permitted.

A memory management system for converting a logical address into a physical address, comprising:

• access permission memory means for storing access permissions for accesses from each program allocated to a logical address space with respect to the logical address;
• verification means for verifying whether accesses from a currently executing program with respect to the logical address are permitted, according to the access permissions stored in the access permission memory means;
• and
• means for outputting the physical address converted from the logical address when the verification means verifies that the accesses from the currently executing program with respect to the logical address are permitted.

A memory management and protection system, comprising:

• program allocation means for determining an allocation of a plurality of programs to at least one of logical address spaces, where only up to a predetermined number of the programs are allocated to each logical address space, and any one address region allocated to any one of the programs does not overlap with any other address regions allocated to any other ones of the programs within said at least one of the logical address spaces;
• memory protection means for detecting an occurrence of an improper access from one address region allocated to one of the programs to another address region allocated to another one of the programs, among said up to the predetermined number of the programs allocated to said each logical address space;
• cache means for storing data to be accessed by the programs;
• and
• processing means for executing the programs by making accesses to the cache means according to the allocation determined by the program allocation means, unless the memory protection means detects the occurrence of the improper access.

A method of memory management for converting a logical address into a physical address in a computer which executes a plurality of programs allocated to a virtual space in parallel by activating a plurality of threads, the method comprising the steps of:

• storing, in an access permission memory means, access permissions indicating whether each thread is permitted to make accesses to the logical address;
• storing a thread number assigned to a currently executing thread which is currently executing the programs;
• verifying whether the currently executing thread specified by the thread number is permitted to make accesses to the logical address, according to the access permissions stored in the access permission memory means;
• and
• outputting the physical address converted from the logical address when the verifying step verifies that the currently executing thread is permitted to make accesses to the logical address.

A method of memory management for converting a logical address into a physical address in a computer which executes programs allocated to a virtual space divided into a plurality of address regions, the method comprising the steps of:

• storing, in an access permission memory means, access permissions indicating whether accesses from each program allocated to each address region to the logical address are permitted;
• detecting a current address region containing a currently executing program which makes an access to the logical address;
• verifying whether the accesses from the current address region detected at the detecting step to the logical address are permitted, according to the access permissions stored in the access permission memory means;
• and
• outputting the physical address converted from the logical address when the verifying step verifies that the accesses from the current address region to the logical address are permitted.

A method of memory management for converting a logical address into a physical address, comprising the steps of:

• storing, in an access permission memory means, access permissions for accesses from each program allocated to a logical address space with respect to the logical address;
• verifying whether accesses from a currently executing program with respect to the logical address are permitted, according to the access permissions stored in the access permission memory means;
• and
• outputting the physical address converted from the logical address when the verifying step verifies that the accesses from the currently executed program with respect to the logical address are permitted.