Browse Prior Art Database

Technique to Bypass Windows 95 Operating System Ring Transition Limitations

IP.com Disclosure Number: IPCOM000118100D
Original Publication Date: 1996-Sep-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Cramer, KD: AUTHOR [+3]

Abstract

The Windows 95* Operating system public Application Programming Interface (API) provides a way to perform ring transitions from ring three programs to ring 0 device drivers. This invention is an alternative way of performing this function which overcomes critical kernel processing limitations.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Technique to Bypass Windows 95 Operating System Ring Transition Limitations

      The Windows 95* Operating system public Application Programming
Interface (API) provides a way to perform ring transitions from ring
three programs to ring 0 device drivers.  This invention is an
alternative way of performing this function which overcomes critical
kernel processing limitations.

      This invention is a technique that allows a ring level 0 device
driver to communicate with a ring level three program at any time as
follows:
  1.  The ring level 0 device driver hooks into the Intel interrupt
       vector trap gate for divide by zero errors (int 0).  In
       effect, the device driver receives control from the operating
       system whenever a divide by zero occurs.
  2.  The ring level three program issues a divide by zero
       error instruction on purpose, in order to perform a ring
       transition, and pass parameters to the ring level 0 device
       driver.
  *  Trademark of Microsoft Corporation