Browse Prior Art Database

Data Exchange Adapter for Micro Channel/370

IP.com Disclosure Number: IPCOM000121880D
Original Publication Date: 1991-Oct-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 4 page(s) / 117K

Publishing Venue

IBM

Related People

Boguski, MJ: AUTHOR [+5]

Abstract

Disclosed here is a unique hardware adapter that provides safe and simple data exchange between a MICRO CHANNEL* system and a MICRO CHANNEL 370 (MC/370).

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Data Exchange Adapter for Micro Channel/370

      Disclosed here is a unique hardware adapter that provides
safe and simple data exchange between a MICRO CHANNEL* system and a
MICRO CHANNEL 370 (MC/370).

      The figure depicts the Data Exchange Adapter (DEA) attachment
to a MICRO CHANNEL 370 and PS/2* systems, with the details of DEA
shown in the dotted lined box.  The DEA hardware employs
off-the-shelf components that are used in ES/9370* IOPs, standard
vendor components, and custom logic. The main hardware components
are:
      o    Motorola 68000 microprocessor
      o    Blue/SPD bus adapter (TIBER)
      o    SPD/M68000 bus adapter (BASE-Z)
      o    High speed data buffer
      o    M68450 DMA controller
      o    M68000 Control storage
      o    MICRO CHANNEL control and data steering logic

      The adapter establishes its unique personality via new 68000
microcode which:
      o    Processes System/370* (S/370) I/O instructions to prepare
for or terminate S/370 data accesses by the MICRO CHANNEL system.
      o    Signals (interrupts) the MICRO CHANNEL system when S/370
events occur and interrupts S/370 when MICRO CHANNEL system events
occur.
      o    Provides a simple memory mapped interface to the MICRO
CHANNEL system which allows accesses of S/370 memory without danger
of corruption of the MICRO CHANNEL 370 system.

      The figure shows that the PS/2 is allowed access to S/370
memory via a high-speed BUFFER STORE on the DEA.  The MC68000
microcode on the DEA manages S/370 memory data accesses requested by
or for the PS/2, as directed by S/370 architecture.  Thus, the DEA
takes on the responsibility of protecting the MICRO CHANNEL 370
system.

      The S/370 control program allocates S/370 memory which is to be
shared by the PS/2 and S/370 and then tells the DEA of this
allocation.  This is accomplished by S/370 issuing a SIO instruction
(Prepare CCW) to the DEA.  The DEA, in response to the SIO, then
maintains the addresses and controls associated with the shared S/370
memory.

      Before the PS/2 can access S/370 memory data via BUFFER STORE
on the DEA, the PS/2 must first issue an Enable command to the DEA.
The DEA in response to the Enable command will tell the PS/2 the
S/370 side status.

      When S/370 and the PS/2 are properly enabled as outlined above,
S/370 memory data accesses are allowed through the DEA by the PS/2.

      The PS/2 can write data to S/370 memory by first writing the
data to BUFFER STORE on the DEA and then issuing a Write command to
the DEA.  The DEA in response to the Write...