Abstract: A system, method, and computer readable medium for eliminating unnecessary ring transitions is described. Often, a requested system service or I/O operation can be performed entirely at a higher ring level, such as Ring 3, with no need to transition to a lower ring. In these cases, the software interrupt or I/O instruction which generates the ring transition is replaced by a call to a program executing at the higher ring level. Thus, the software interrupt instruction or I/O instruction is redirected to code that resides at the same protection level and emulates the effects of the instruction, resulting in improved execution speed. In the Intel 80×86 family of microprocessors, both the software interrupt instruction and the I/O instruction take two bytes to encode. It is thus possible to replace the instruction with the op-code for a segment:offset far call, letting the instruction stream dictate the offset for the call.

Abstract: A method of managing connection requests from an application supported on a client. The client has a modem connectable to at least one server via a dialup computer network. According to the method, a list is maintained of the local Internet Protocol (IP) addresses assigned as modem connections are established to the dialup computer network during a session. The list is preferably in Last In, First Out (LIFO) order and includes a latest IP address as the last entry and one or more stale IP addresses. In response to a connection request associated with a stale IP address, the stale IP address is mapped to the latest IP address. The connection request is then redirected using the latest IP address. Preferably, client supports a proxy server which services the connection request locally if possible to avoid network traffic.