For this purpose, the cache has a special flag for each block of memory it stores, called the dirty bit -- which might just be the best term computer scientists have ever invented.

为此，缓存为它存储的每个内存块都有一个特殊的标志，称为脏位——这可能是计算机科学家发明的最好的术语。

Before the cache erases the old block to free up space, it checks its dirty bit, and if it's dirty, the old block of data is written back to RAM before loading in the new block.

在缓存擦除旧块以释放空间之前，它会检查其脏位，如果它是脏的，则在加载新块之前将旧数据块写回 RAM。