Generic software interface for hardware environments

Abstract

A generic interface layer for providing a generic interface to a hardware environment for a program executing on the hardware environment. The generic interface layer is interrupt-driven. It includes driver code for devices in the hardware environment that is executed in response to software interrupts from the program and interrupt handling code for handling interrupts from the hardware environment. The interrupt handling code responds to an interrupt by calling a callback in the program. The generic interface layer includes a loader for loading the program and a debugger for controlling execution of the program. Execution of code in the generic interface layer may be coordinated by the system timer interrupt code that is executed in response to a system timer interrupt. Code that is executing in the generic interface layer may register itself or other code with the system timer interrupt code, which then executes the code in response to a system timer interrupt. One use of the technique is to permit driver code to register other code and then quickly return to the program and thereby prevent long suspension of the program. Also disclosed is a technique for managing a statically-allocated array of buffers for receiving LAN packets to reduce the frequency of an "out of resource" condition.

Description

[0001] The present application is a divisional of USSN 09 / 277,414, which has the same inventor, title, and assignee as the present application and which is hereby incorporated into the present application by reference.[0002] 1. Field of the Invention[0003] The invention relates generally to interfaces used by programs to control and respond to components of a computer system and more specifically to the interfaces used by programs to control and respond to hardware environments.[0004] 2. Description of the Prior Art[0005] When all is said and done, what a computer program does is control and respond to hardware devices. When a user types a character on the keyboard, the program executing on the computer system responds to the input from the keyboard hardware by causing the computer system to execute instructions which in turn cause the display terminal to display the typed character. Because the computer program controls and responds to hardware devices, the instructions in the prog...

AI Technical Summary

Benefits of technology

"The patent text discusses the problem of computer programs relying on the hardware environment in which they run. When a program is written, it is designed to work with a specific hardware system. However, when a new hardware system is introduced, the program may not work correctly without being rewritten. This is a time-consuming and difficult process. The patent proposes a solution to make it easier to port operating systems to new hardware environments."

Problems solved by technology

A program written for a system with one kind peripheral device will not work on a system that uses a different kind of peripheral device, even though both systems have a computer that executes the same instruction set.

For example, a program written for one kind of keyboard will not work with another kind of keyboard.

Compilers have not, however, been able to solve the problem of dealing with differing peripheral devices.

However, as one would expect from the role of the operating system in dealing with the hardware environment, operating systems are not portable.

Porting an operating system is difficult, slow, and requires an extensive knowledge of both the new hardware environment 102 and at least the hardware-dependent code and data portion of the operating system.

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