Using nvSRAM in RAID Controller Applications
stored simultaneously in several different locations,
and parity information is being maintained to allow
recovery in case of disk failure. This constant mov-
ing of data and reconfiguring of the array, requires
that the configuration address vectors be stored in a
nonvolatile technology that is rapidly rewritable. This
memory must be fast enough to run at processor
bus speeds so the RAID controller does not have to
waste time blindly searching the disk array for its
configuration data.
rity of a less dynamic technology. This part has high
applicability to RAID controllers for address vector
and configuration storage.
The STK12C68/STK14C88 Family
The SIMTEK STK12C68/STK14C88 AutoStore™
family combines the flexibility of the 10Cxx family,
the data security of the 11Cxx family, and adds the
capability to perform power down AutoStore™ to
assure that data is never lost.
The SIMTEK family of nonvolatile SRAM products
are ideally suited to RAID applications. They run at
processor speeds, require no batteries for nonvola-
tility, are standard size and shape for automatic
manufacturing, and are flow solderable. The high
number of nonvolatile stores (1 Million), fast read
and write times (20 ns), and fast store times (10 ms)
allows the design of highly efficient embedded con-
trollers for both commercial and home applications.
The 12C68/14C88 family uses the same STORE
and RECALL techniques that are used with the
10Cxx and 11Cxx parts, but also gives the design
engineer the flexibility of automatically storing on
power down. AutoStores™ are autonomously per-
formed (unless inhibited) when system power falls
below VSWITCH (about 4.25 V). This assures that
data is always safe and requires no batteries or
other power sources that are prone to failure. RAID
controllers that are dynamically keeping track of
address vectors, system configuration, and disk
error recovery information are ideal applications for
this family of parts.
Applying SIMTEK nvSRAM To Modern
RAID Controllers
The STK10Cxx Family
Conclusion
The SIMTEK STK10Cxx family of nvSRAMs is a
high performance nonvolatile memory family that is
designed for easy interface to embedded control-
lers. The STK10Cxx family is designed for dynamic
applications that require easy transfer from SRAM
to nonvolatile memory under processor control.
Using the 10Cxx family for store and recall of
address vectors, configuration databases, and error
detection/correction codes is an ideal application.
Modern RAID Controllers offer high data reliability
and increased I/O performance in one package.
This requires that the RAID system designer utilize
the latest in high performance embedded proces-
sors, state-of-the-art software, and sophisticated
control algorithms.
The flexibility of fast nonvolatile memory for the stor-
age of RAID address vectors, system configuration
information, and adaptive algorithm memory is
becoming more apparent with each new generation
of system. SIMTEK’s family of fast nvSRAMs are
ideally suited to this type of high performance appli-
cation. They run at processor speeds with no wait
states, reliably store data in a nonvolatile semicon-
ductor memory without batteries, and look to the
processor like a standard SRAM. Ease of imple-
mentation and ability to rapidly change data, as well
as the ability to use modern manufacturing tech-
niques, helps to reduce costs and to speed product
to market.
Data within the SRAM is stored to nonvolatile mem-
ory by simply requesting an SRAM write with the NE
line active. This transfers data from the SRAM to
shadow EEPROM in 10 ms. Data in the EEPROM is
then completely nonvolatile and requires no batter-
ies, capacitors or other energy sources to remain
stored for 10 years.
The STK11Cxx Family
The SIMTEK STK11Cxx family of nvSRAMs is
designed for use in applications where data must be
safely maintained in a fast nonvolatile memory, but
does not require the dynamic store capability of the
STK10Cxx family.
The STK11Cxx family of parts uses a software store
and recall system that allows the flexibility of a fast
nonvolatile SRAM memory, but offers the data secu-
8-28
SIMTEK [ SIMTEK CORPORATION ]
