User guide

Overview, Continued
Performance
Features
EF5XX-series disks offer powerful performance features that
are not typically available on disk storage devices in this form
factor. Table 1–1 lists some of these features:
Table 1–1 EF5XX Series Performance Features
Feature Function
Multihost support This allows a single ISE to be used by more than one host
at the same time. For example, two VAX4000 systems
can be booted from a single ISE.
670-bit Error
Correction Code
(ECC)
EF5XX ISEs store a large, 670-bit ECC in each block,
capable of correcting up to 320 erroneous bits.
Controller-
initiated Bad
Block Replacement
(BBR)
With controller-initiated BBR, the ISE presents the
host with a set of logically contiguous blocks, and
disk capacity does not decrease because bad blocks
are detected and automatically moved to spare blocks.
Replacement
Control Table
(RCT) Cache
DSSI ISEs cache the RCT allowing replaced blocks to
be located without the time required to access the RCT
stored on the media.
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