Abstract: An implementation of PCMCIA Card Services for the Windows operating system in enhanced mode. A Card Services dynamic linked library (DLL) was written which contains a library of C functions which perform the Card Services functions. The Card Services DLL maintains a Card Services database of the Card Services resources available such that the Card Services DLL can share the Card Services resources among clients of Card Services. Windows applications can call the functions in the Card Services DLL directly to access Card Services functions. The Card Services DLL posts messages to a Card Services Windows application to request a Card Services function be performed with background processing. The Card Services Windows application processes the Card Services function at a later time. A Card Services virtual device driver (V.times.D) provides system functions to the Card Services DLL. The Card Services V.times.

Abstract: A library of C functions to perform PCMCIA Card Services. A PCMCIA Card Services specification defines a set of functions which allow applications and device drivers to access PCMCIA Cards. The PCMCIA Card Services specification provides a register based software interrupt binding to access the Card Services functions. A library of C functions is defined which can be called to perform the Card Services functions. The library of C functions can reformat the function parameters and then call a Card Services provider with a standard register based software interrupt binding. Alternatively, the library of C functions can be a fully protected mode implemenation of Card Services.

Abstract: Background processing for PCMCIA card service functions for registered Card Services clients includes a Card Services Background Processing Application and a Card Services dynamic link library (DDL) residing in the system VM, and a Card Services VxD residing in priority ring 0. A request for a Card Services function is generated by a Card Services function requester. The Card Services function requester is either a Card Services Client or a PCMCIA socket adapter. In response to the request, the Card Services VxD sets-up a path between the Card Services function requester and the Card Services DLL. The Card Services DLL contains the Card Services functions, and the appropriate Card Service function is executed. If the Card Service function requested requires background processing, the Card Services DLL posts a message with the Card Services Background Processing Application. The Card Services DLL then acknowledges the request for Card Services function to the Card Services requester.

Abstract: A computer system contains an Intel.TM. 80386 or later microprocessor as a central processing unit (CPU) and a system memory coupled to the CPU. The computer system runs Microsoft.TM. Windows v. 3.1 operating system in enhanced mode. The system memory contains a system virtual machine (VM) and at least one DOS VM. A target VM contains shared code routines for use by all VMs loaded in the computer system. When access to the shared code routine is desired from a calling process in a calling VM, the calling VM transfers control and calling data parameters to a shared code virtual device driver (VxD). The shared code VxD performs data translation for the calling data parameters so that the target VM can access the data parameters. The shared code VxD invokes calls to a Windows Process scheduler to schedule the target VM and block selection of the calling VM. The target VM, upon invocation by the scheduler, executes the shared code routine and generates return parameters.