ZiLOG System 8000 Hardware Reference Manual

HRM
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HRM
buffer which permits the transfer of 24 512-byte sectors in
one disk revolution.
1.2.3. storage Module Device Controller (SMDC): The SMDC
is a high performance controller (1.8 MB/second max. data
rate) linking the system ZBI backplane to the industry stan-
dard storage Module Device (SMD) interface. The SMDC con-
sists of two cards, SMDC A and SMDC B. Card A connects to
the ZBI at the 96-pin board connector P1. It also connects
to the SMD A daisy-chain cable at plug P2. Card B connects
to four SMD B radial cables. All drive connections are
through the P2 backplane connector.
Bit slice processor and sequencer logic control all the
operations of the SMDC. The SMDC can control up to four
eight inch drives that have SMD interface. SMDC features
include packet control, overlapped seek, automatic error
recovery, data buffering, flagged sectors, long writes and
reads, and self-test on power-up or system initialization.
The SMDC can be interrupt driven or operate in the polled
mode to the host when a packet is complete. It gives a com-
plete status report of the SMD and the controller.
1.2.4. Tape Cartridge Controller (TCC): The tape con-
troller is the intelligent interface between the CPU and up
to four cartridge tape drives. A Zilog Z80B microprocessor
controls the operation of the controller. The controller
uses direct-memory access (DMA) to transfer data between the
cartridge tape drive and the CPU. When the CPU wants to
initiate an operation, it sends a command to the controller.
The controller completes the specified operation and then
interrupt~ the CPU to notify it that the ope~ation is com-
plete.
1.2.5. M4~mory Subsystem: The Memory Subsystem includes an
Error Checking and Correcting (ECC) Controller board and one
or more Memory Array boards.
The ECC Controller can control the operation of up to 4
megabytes of dynamic read/write memory. The data can be
t ran s fer r l~ d as by t es (e i g ht bit s), wo r ds (1 6 bit s), 0 rIo ng
words (32 bits); the controller translates the width of the
data and places the data in the proper locations. The con-
troller transparently corrects all single-bit errors (soft)
and detects all double-bit errors (hard). The controller
uses a soft-error logging system that counts soft errors in
each 64K-byte block of memory.
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ZiLOG System 8000 Specifications

General

Brand	ZiLOG
Model	System 8000
Category	Desktop
Language	English