Method and apparatus for supporting read-only objects within an object-addressed memory hierarchy

An apparatus that supports read-only objects within an object-addressed memory hierarchy, comprising:

• a receiving mechanism configured to receive a request at a translator to access an object, wherein the request includes an object identifier for the object that is used to reference the object within the object-addressed memory hierarchy, and wherein the translator converts an object identifier and offset into a corresponding physical address and converts the request to access an object into a request for the corresponding physical address;
• a translation mechanism configured to use the object identifier to retrieve an object table entry associated with the object;
• and
• a corrective action mechanism, wherein if the request is a write request, the corrective action mechanism is configured to,
• examine a read-only indicator within the object table entry, and
• if the read-only indicator specifies that the object is a read-only object, to perform a corrective action to deal with the fact that the write request is directed to a read-only object, wherein performing the corrective action involves:
• obtaining a writable copy of the object, clearing the read-only indicator to indicate that the object is no longer read-only, and updating the writable copy of the object with data from the write request;
• updating a remotely located master copy of the object with data from the write request;
• terminating the requesting process because the write request is not allowed;
• and
• if the request is directed to a debugging breakpoint, pausing the requesting process and clearing the read-only indicator.

A computer system that supports read-only objects within an object-addressed memory hierarchy, comprising:

• a processor;
• the object-addressed memory hierarchy;
• an object cache within the object-addressed memory hierarchy;
• a translator that translates between object identifiers, used to address objects in the object cache, and physical addresses, used to address objects in main memory;
• a receiving mechanism within the translator configured to receive at the translator a request to access an object, wherein the request includes an object identifier for the object that is used to reference the object within the object-addressed memory hierarchy, and wherein the translator converts an object identifier and offset into a corresponding physical address and converts the request to access an object into a request for the corresponding physical address;
• a translation mechanism within the translator configured to use the object identifier to retrieve an object table entry associated with the object;
• and
• a corrective action mechanism, wherein if the request is a write request, the corrective action mechanism is configured to,
• examine a read-only indicator within the object table entry, and
• if the read-only indicator specifies that the object is a read-only object, to perform a corrective action to deal with the fact that the write request is directed to a read-only object, wherein performing the corrective action involves:
• obtaining a writable copy of the object, clearing the read-only indicator to indicate that the object is no longer read-only, and updating the writable copy of the object with data from the write request;
• updating a remotely located master copy of the object with data from the write request;
• terminating the requesting process because the write request is not allowed;
• and
• if the request is directed to a debugging breakpoint, pausing the requesting process and clearing the read-only indicator.