Method for communicating information between independently loaded, concurrently executing processes

• US 5,175,855 A
• Filed: 07/27/1987
• Issued: 12/29/1992
• Est. Priority Date: 07/27/1987
• Status: Expired due to Term

• Current Assignee: National Instruments Corporation (Emerson Electric Company)
• Original Assignee: Laboratory Technologies Corporation
• Inventors: Putnam, Frederick A., Rhoads, John G.
• Primary Examiner(s): Popek, Joseph A.
• Assistant Examiner(s): Rudolph, Rebecca L.
• Application Number:
  US07/078,369
• Time in Patent Office: 1,982 Days
• Field of Search: 364/200 MS File, 364/900 MS File
• US Class Current: 719/321
• CPC Class Codes: G06F 9/54 Interprogram communication

Abstract

A subprogram which operates as a MS/PC-DOS device driver provides a communication path between a data acquisition program which operates as an interrupt driven memory-resident program in background and a conventional data analysis program which operates in foreground. Information transfers are initiated by the foreground program which issues standard I/O requests to the DOS, identifying the device driver and the information storage area within the foreground address space from which or to which the information is to be communicated. The device driver subprogram relays the information to the background process by calling the background program at an entry point which is made available to the device driver at a predetermined interrupt vector location, enabling the device driver to pass the memory address of the foreground storage area, together with the size of the block of information to be communicated, to the background program. The background program operates in a selected one of several possible modes, one of which waits for data to supplied from an external data acquisition instrument before returning control to the foreground process so that the two processes can operate in synchronism.

Claims

1. The method of communicating between background and foreground processes which operate on data stored within background and foreground regions respectively of a random access memory, said background and foreground processes being independently loaded by and concurrently executed under the supervisory control of an operating system which implements installable device drivers, said method comprising, in combination, the steps of:

requesting the operating system to load a special-purpose installable device driver into memory, said device driver being adapted to relay an I/O request from said operating system to an interface routine located at an entry point address, the value of said entry point address being stored at a predetermined memory location,

requesting the operating system to load a background program into memory for carrying out said background process, said background program including said interface routine which comprises instructions for transferring information between said background region and said foreground region, the location of said foreground region being specified by a transfer address contained in said I/O request relayed to said background process via said device driver from said operating system,

determining the run-time address of the entry point of said interface routine as loaded by said operating system and storing said run-time address in said predetermined memory location, and

requesting the operating system to load a foreground program in said memory for carrying out said foreground process, said foreground program including a routine which supplies an I/O request to said operating system, said I/O request containing information identifying said special-purpose device driver and further specifying said tranfer address.

2. The method of communicating set forth in claim 1 wherein said special-purpose device driver relays said I/O request to said background process by passing control over the instruction execution sequence from the operating system to the instruction stored at the entry point specified by the run-time address stored at said predetermined memory location.

3. The method of communicating set forth in claims 1 or 2 wherein said background program further comprises instructions for placing data acquired from an external peripheral instrument into said background region of said random access memory.

4. The method of communicating set forth in claim 3 wherein said interface routine includes instructions for returning control to said foreground process only after a data item requested in a pending I/O request has been received from said external peripheral instrument and placed in said background storage location.

5. In a data processing system employing a memory and an operating system program, a method for transferring information between concurrently executing background and foreground programs which comprises, in combination, the steps of

requesting the operating system to install a special-purpose device driver routine which is adapted to call an interface procedure, the first instruction of which is located at an run-time entry point address specified by the contents of a predetermined memory location,

requesting the operating system to load said background program into memory and to begin executing said background program, said background program comprising instructions for performing said interface procedure and further comprising, in combination,

instructions for determining the said run-time entry point address of said interface routine as loaded by the operating system and for storing said run-time address in said predetermined memory location,

instructions for processing information stored in a background memory region, and

an instruction for returning control to said operating system leaving said background program loaded in memory,

requesting the operating system to load said foreground program into main memory for processing information stored in a foreground memory region, said foreground program including instructions for issuing input-output requests for the transfer of information between said background and foreground memory regions.

6. A method for transferring information as set forth in claim 5 wherein said background program is an interrupt-driven data acquisition routine for storing data from an external peripheral data collection device in said background region.

7. A method as set forth in claim 6 wherein said interface routine awaits the receipt of at least one data item from said collection device before returning control to said foreground program to thereby synchronize the execution of said foreground and background programs.

8. A method as set forth in claims 6 or 7 wherein said data acquisition routine is called at intervals by a hardware-generated clock interrupt.