An interface architecture includes a plurality of pipelines each controlled
by a respective line processor. An onboard ESCON protocol conversion
device distinguishes customer data to be stored on a disk or read from
disk versus header information. Transmit and receive frame dual port rams
store transmitted frame and received frame information, stripping
frame/header information from user data. Data to be stored in Global
Memory is stored temporarily in FIFOs. An assembler/disassembler in each
pipeline receives data from FIFOs (on a write), and transfers data to
FIFOs (on a read). A buffer dual port ram (DPR) is configured to receive
data for buffering read operations from and write operations to the GM.
Data transfers between the assembler/disassembler and the buffer DPR pass
through Error Detection And Correction circuitry (EDAC). A plurality of
state machines arranged as an Upper Machine, Middle Machine and Lower
Machine facilitate movement of user data between DPR and Global Memory
(GM). Substantial shared resources including a service processor provides
configuration and maintenance services.