Supervisory method for a computer operating system

Claim 1

A method for the supervision by one or more processing programs of the normal programmed response of a computer to the occurrence of a type of inter­rupt event, said normal programmed response to such an interrupt event including the steps of (i) retrieving from an entry in addressable storage the address of a normal interrupt-handling (IH) routine (the normal IH-address) corresponding to the type of occuring interrupt event, and (ii) executing the normal IH routine stored in addressable storage at said normal IH-address, said method comprising the steps of: A. making a copy of the normal IH-address in addressable storage; B. storing a supervisor IH routine in addressable storage; C. overwriting said normal IH-address entry with the address of said supervisor IH routine; D. in response to any calling of said supervisor IH routine, sequentially calling one or more selected supervisor programs; E. the programming in each said supervisor program including a decision branch whether to invoke the normal IH routine in response to the interrupt event occurrence, the outcome of said decision branch depending in part on whether any other supervisor program has already invoked the normal IH routine; and F. upon the completion of the sequential invocation of selected supervisor programs, invoking the normal IH routine if no supervisor program has done so.

Claim 2

A method for the supervision by one or more processing programs of the normal programmed response of a computer to the occurrence of a type of inter­rupt event, said normal programmed response to such an interrupt event including the steps of (i) retrieving from an entry in addressable storage the address of a normal interrupt-handling (IH) routine (the normal IH-address) corresponding to the type of occuring interrupt event, and (ii) executing the normal IH routine stored in addressable storage at said normal IH-address, said method comprising the steps of: A. making a copy of the normal IH-address in addressable storage; B. storing a supervisor IH routine in addressable storage; C. overwriting said normal IH-address entry with the address of said supervisor IH routine; D. in response to any calling of said supervisor IH routine, sequentially calling one or more selected supervisor programs; E. the programming in each said supervisor program including a decision branch whether to invoke the normal IH routine in response to the interrupt event occurrence, the outcome of said decision branch depending in part on whether any other supervisor program has already invoked the normal IH routine; and F. upon the completion of the sequential invocation of selected supervisor programs, invoking the normal IH routine if no supervisor program has done so.

Claim 3

A system for the distributed supervision and selective modification of the normal programmed response of a computer to the occurrence of a type of interrupt event, said normal programmed response to such an interrupt event including the execution of a normal interrupt-­handling (IH) routine that corresponds to the type of interrupt event occurrence, said normal IH routine being stored at a location in addressable storage pointed to by a primary normal-IH pointer, said primary normal-IH pointer itself being stored in a formatted area of addressable storage, said computer having one or more registers, said system comprising: A. a substitute IH routine; B. a substitute-installing routine including instructions for 1) creating a backup normal IH pointer in a formatted area of addressable storage which points to the address of said normal IH routine, and 2) subsequently overwriting said primary normal IH pointer with a pointer to the ad­dress of said substitute IH routine; C. a dispatcher routine called in response to any calling of said substitute IH routine, said dispatcher routine including instructions for calling one or more supervisor programs, wherein the instructions of each said supervisor program include 1) a decision branch whether said normal IH routine should be called by said particular supervisor program in response to the interrupt event occurrence, the outcome of said decision branch depending in part on whether any other supervisor program has already made such a call, 2) instructions for calling the normal IH routine if so indicated by the outcome of said decision branch, and 3) instructions for returning program control to the program which called the supervisor program; and D. a backup normal-IH caller routine that is called subsequent to the completion of said calling of said supervisor programs, said backup normal-IH caller routine including instructions for calling said normal IH routine if none of said called supervisor programs called the normal IH routine in response to the occurrence of the interrupt event.

Claim 4

A system for the distributed supervision and selective modification of the normal programmed response of a computer to the occurrence of a type of interrupt event, said normal programmed response to such an interrupt event including the execution of a normal interrupt-­handling (IH) routine that corresponds to the type of interrupt event occurrence, said normal IH routine being stored at a location in addressable storage pointed to by a primary normal-IH pointer, said primary normal-IH pointer itself being stored in a formatted area of addressable storage, said computer having one or more registers, said system comprising: A. a substitute IH routine; B. a substitute-installing routine including instructions for 1) creating a backup normal IH pointer in a formatted area of addressable storage which points to the address of said normal IH routine, and 2) subsequently overwriting said primary normal IH pointer with a pointer to the ad­dress of said substitute IH routine; C. a dispatcher routine called in response to any calling of said substitute IH routine, said dispatcher routine including instructions for calling one or more supervisor programs, wherein the instructions of each said supervisor program include 1) a decision branch whether said normal IH routine should be called by said particular supervisor program in response to the interrupt event occurrence, the outcome of said decision branch depending in part on whether any other supervisor program has already made such a call, 2) instructions for calling the normal IH routine if so indicated by the outcome of said decision branch, and 3) instructions for returning program control to the program which called the supervisor program; and D. a backup normal-IH caller routine that is called subsequent to the completion of said calling of said supervisor programs, said backup normal-IH caller routine including instructions for calling said normal IH routine if none of said called supervisor programs called the normal IH routine in response to the occurrence of the interrupt event.

Claim 10

A method for the distributed supervision and selective modification of the normal programmed response of a computer to the occurrence of a type of interrupt event, said normal programmed response to such an interrupt event including the execution of a normal interrupt-­handling (IH) routine that corresponds to the type of interrupt event occurrence, said method comprising the steps of: A. intercepting each call to said normal IH routine; B. calling in turn each of one or more supervisor programs, each of said supervisor programs including a decision branch whether to re-call said normal IH routine, the outcome of said decision branch depending in part on whether any other supervisor program has already re-called said normal IH routine; and C. if none of said supervisor programs re-calls said IH routine, re-calling said IH routine.

Claim 11

A method for the distributed supervision and selective modification of the normal programmed response of a computer to the occurrence of a type of interrupt event, said normal programmed response to such an interrupt event including the execution of a normal interrupt-­handling (IH) routine that corresponds to the type of interrupt event occurrence, said method comprising the steps of: A. intercepting each call to said normal IH routine; B. calling in turn each of one or more supervisor programs, each of said supervisor programs including a decision branch whether to re-call said normal IH routine, the outcome of said decision branch depending in part on whether any other supervisor program has already re-called said normal IH routine; and C. if none of said supervisor programs re-calls said IH routine, re-calling said IH routine.

Claim 12

A method for distributed supervision of the execution of a normal interrupt handling routine called by a calling program within a computer system operating environment, comprising the steps of: A. intercepting each call to said normal interrupt handling routine; B. upon each such call, creating a memory model in addressable storage of the then-existing state of the environment; C. passing a pointer to said memory model as an argument in a call to a supervisor program; D. upon any call by said supervisor program for execution of said normal interrupt handling routine, updating the environment to reflect the then-existing state of the memory model; E. calling the normal interrupt handling routine; F. updating the memory model to reflect the then-­existing state of the environment; G. returning control to the calling supervisor program; H. receiving control back from the calling supervisor program; I. if no said supervisor program has called for execution of said normal interrupt handling routine, calling for said execution; J. conforming said environment to said existing state of the memory model; and K. returning control to said calling program.

Claim 13

A method for distributed supervision of the execution of a normal interrupt handling routine called by a calling program within a computer system operating environment, comprising the steps of: A. intercepting each call to said normal interrupt handling routine; B. upon each such call, creating a memory model in addressable storage of the then-existing state of the environment; C. passing a pointer to said memory model as an argument in a call to a supervisor program; D. upon any call by said supervisor program for execution of said normal interrupt handling routine, updating the environment to reflect the then-existing state of the memory model; E. calling the normal interrupt handling routine; F. updating the memory model to reflect the then-­existing state of the environment; G. returning control to the calling supervisor program; H. receiving control back from the calling supervisor program; I. if no said supervisor program has called for execution of said normal interrupt handling routine, calling for said execution; J. conforming said environment to said existing state of the memory model; and K. returning control to said calling program.