Multiprotocol I/O communications controller unit including emulated I/O controllers and tables translation of common commands and device addresses

• US 4,855,905 A
• Filed: 04/29/1987
• Issued: 08/08/1989
• Est. Priority Date: 04/29/1987
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Estrada, Suzanne L., Ploger, Robert R. III
• Primary Examiner(s): Williams, Jr., Archie E.
• Assistant Examiner(s): Coleman, Eric
• Application Number:
  US07/043,798
• Time in Patent Office: 832 Days
• Field of Search: 364/200 MS File, 364/900 MS File, 364/ 200
• US Class Current: 709/246
• CPC Class Codes: G06F 13/102 where the programme performs an interfacing function, e.g. device driver G06F13/105 takes precedence; scheduling within device drivers G06F9/52; contention policies within device drivers G06F9/4881
• CPC Class Codes: H04L 69/18 Multiprotocol handlers, e.g. single devices capable of handling multiple protocols

Abstract

The improved I/O controller includes a data processing element for executing a sequence of stored program instructions to control the transfer of data between respective ones of a plurality of I/O devices and the host computer. The controller further includes a memory element for storing the program instructions and parameter tables associated with the transfer of data. A first sequence of stored program instructions defines a first communications protocol and a second sequence of stored program instructions defines a second communications protocol. A first control table is associated with a first I/O device, for relating the first device to the first program instructions and a second control table is associated with a second I/O device, for relating the second I/O device to the second program instructions. The first table is invoked when first data is to be transferred between the first I/O device and a host computer, to call a first program instructions to impose the first communications protocol to govern the transfer of the first data. The second table is invoked when second data is to be transferred between a second, diverse I/O device and the host computer, to call the second program instructions to impose the second communications protocol to govern the transfer of the second data. In this manner, a plurality of communications protocols which are mutually incompatible, can be concurrently executed for communication between a host computer and a plurality of diverse I/O devices.

Claims

1. In a data processing system including a host processor having a channel for communicating commands through a first type I/O control unit to a first terminal or a second terminal having first and second device addresses, respectively, and for communicating commands through a second type I/O control unit to a communications link having a third device address, a multiprotocol I/O communication controller unit coupled between said channel and said terminals and said communications link, said communication controller unit comprising:

a common level control logic means coupled to said channel, for receiving from said channel a device address value and an associated common command value representing a command;

a control unit level control logic means coupled to said common level control logic means and also coupled to said first terminal, to said second terminal and to said communications link, including a first emulated I/O controller for controlling said first and said second terminals and including a second emulated I/O controller for controlling said communications link;

said common level control logic means including a device address translation table for directing said associated common command value to said first emulated I/O controller in response to said device address value being either said first or said second device address and for directing said associated common command value to said second emulated I/O controller in response to said device address value being said third device address;

said first emulated I/O controller including a first command translation table for converting said associated common command value to a first type terminal control command, said control unit level control logic means outputting said first type terminal control command to either said first or said second terminal in response to said device address value being either said first or said second device address, respectively;

said second emulated I/O controller including a second command translation table for converting said associated common command value to a second type communications link control command, said control unit level control logic means outputting said second type communications link control command to said communications link in response to said device address value being said third device address.