Write-back and write through cache

Question

Illustrate the difference between the write-back and write through cache?

Answer 1

The caching method in which, the modifications of data in cache are not copied to cache source till absolutely essential. Write-back caching is available on most of the microprocessors, comprising all Intel processors since 80486. With such microprocessors, data modifications to data stored in the L1 cache are not copied to main memory till absolutely essential. In contrary, a write-through cache performs all write operations in parallel-data are written to main memory and the L1 cache concurrently. Write-back caching yields rather better performance than write-through caching since it decreases the number of write operations to the main memory. With this performance enhancement comes a slight risk which data might be lost if the system crashes.

The write-back cache is as well termed as the copy-back cache.