NEC POWERMATE 2000 Service And Reference Manual page 175

write-back
Also called copy back. A cache strategy where write operations to data stored in the
internal microprocessor L1 cache aren't copied to system memory until absolutely
necessary. In contrast, a write-through cache performs all write operations in
parallel; data is written to system memory and the L1 cache simultaneously. Write-
back caching yields somewhat better performance than write-through caching
because it reduces the number of write operations to main memory. See cache and
write-through.
write-through
Also write-thru. Write-through characterizes a cache strategy where data is always
written into system memory when data is written by the CPU. See cache and write
back.
Glossary 17