System for emulating I/O device requests through status word loc

Details System for emulating I/O device requests through status word loc System for emulating I/O device requests through status word loc

1991-12-31

1994-12-20

Lee, Thomas C.

Boots, shoes, and leggings

395250, 3642394, 3642397, 364DIG1, G06F 1516

Patent

active

053752252

ABSTRACT:
In the system of the present invention, a specialized form of read-ahead, write-behind buffering is provided which enables the host processing system to provide timely responses to device requests that are emulated by the host processor. Each input/output device request is identified by an address to which the device is purportedly mapped to. This address is translated to an address containing a status word for that particular device being emulated. Each status word contains a byte of information either to be sent to the microprocessor as a response during an I/O read operation request by the microprocessor, or to receive data written by the microprocessor in response to an I/O write operation request, and a plurality of status bits which identify the state of the data contained in the I/O status word. Thus, microprocessor I/O write operations may be quickly performed without the need for immediate response by the host processor and responses for various I/O devices emulated can be precomputed and input to the corresponding I/O status words such that when the microprocessor issues a read request to an input/output device the response may be quickly retrieved and returned back to microprocessor with little or no detected response time degradation.

REFERENCES:
patent: 4031517 (1977-06-01), Hirtle
patent: 4084235 (1978-04-01), Hirtle et al.
patent: 4527237 (1985-07-01), Frieder et al.
patent: 4937036 (1990-06-01), Beard et al.
patent: 4947366 (1990-08-01), Johnson
patent: 4954942 (1990-09-01), Masuda et al.
patent: 5068852 (1991-11-01), Locke
P/C Chip Provides High Integration . . . ; Mark Thorson; Oct. 16, 1991.
SPARC meets 386: Two Heads are Better . . . ; Sun User Group; Jun., 1991.
"Use of a Coprocessor for Emulating the PC AT", John W. Irwin, IBM RT Personal Computer Technology, pp. 137-141, 1986.
"Coprocessor Software Support", Rajan Krishnamurty and Terry Mothersole, IBM RT Personal Computer Technology, pp. 142-146, 1986.

Affiliated with

Also associated with

Rating

System for emulating I/O device requests through status word loc does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with System for emulating I/O device requests through status word loc, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System for emulating I/O device requests through status word loc will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2390507