188-183 IBM 7552 Industrial Computer/Extended Memory (0-16MB)
Extended Memory Adapter
|DS1 Run / Check
DS2 Memory Check
S1 Bank 1 ECC SIMM
|S6 Bank 2 ECC SIMM
U47 SDT 49C460BJ
P1,2 Backplane connectors
IDT 49C460 EDC 32-Bit CMOS Error
Detection and Correction Unit
AN-151 USING 32-BIT
EDCS IN 8-BIT AND 16-BIT APPLICATIONS
THE IDT49C460 AND IDT49C465
Error correction ICs for 64-bit word sizes
This IC  is a 32-bit error detection (all single and
double errors and some multiple bit errors) and correction (single errors)
that uses a modified Hamming Code. Seven checkbits are used in 32-bit implementations.
Two ICs can be cascaded for a 64-bit data implementation (in this case,
eight checkbits are used).
The time taken to detect and correct errors is, in the
fastest version -and still preliminary- 14
ns. This time is 23 ns in 64-bit implementations (the syndrome output
from the first IC is cascaded to the second one). The IC uses the same
lines for both data input and output. It takes 7 ns max. to enable/disable
the output buffers. The minimum cycle time is then 30 ns (estimated from
the data shhet), allowing a 33 MHz operation.
IBM 7552 0-16MB EXTENDED MEMORY ADAPTER (#6345):
This extends the memory capacity of the 7552 from 2Mb to 16Mb. The
0-16Mb Extended Memory Adapter is a full-length memory expansion option
with Error Checking and Correction capability (standard with 0Mb of memory
installed). Up to ten (two of which are required for the Error Checking
and Correction feature) 2Mb Memory Module Kits -- 85 ns (#5213) can be added
to the card to provide up to 16Mb of memory. No switch setting is
2MB 85 ns (#5213) (6450604): Mine are 68X6127, OKI MSC2321-85YS18A
PREREQUISITES: If the serial
number of the 7552 Industrial Computer is below 25000, RPQ PF1076 is required
to be installed on the processor card prior to the installation of the
IBM 7552 0-16Mb Extended Memory Adapter (#6345). If the serial number
of the 7552 Industrial Computer is above 25000, RPQ PF1076 is not required.
RPQ PF1076 contains a BIOS chip set, removal tool, insertion tool, diagnostic
diskette and installation instructions.