PCH6-RAM Basics <<
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Memory Modules
One of the uses of memory is to serve as a disk cache. Like the caches we mentioned in the processor, the RAM acts as a faster, temporary storage area for recently used and commonly used data from the hard drive. Because it is quicker to access RAM than to seek out the data in the hard drive’s sectors, RAM increases the performance of the machine. Disk caching can be used only when there is available extra space in the memory. But what happens if you do not have enough physical memory available? When there is not enough physical memory, the computer creates virtual memory. Virtual memory is sometimes referred to as "page files" or “swap files.” Virtual memory is a slow substitute for RAM since it is a temporary file created on the hard drive and emulates the physical RAM. Essentially, disk caching allows RAM to act like an extremely fast hard drive, while virtual memory consists of files on the hard drive acting as extremely slow memory. RAM is faster than either magnetic storage (like hard drives and floppy disks) or optical storage (DVD, CD, Blu-ray). This is because RAM is a solid-state device without exceedingly long access times. RAM operates in the billionths of a second (nanoseconds), while hard drives and other magnetic media are very slow, operating in the thousandths of a second (milliseconds). Insufficient RAM causes a computer to operate more slowly. So, upgrading RAM is one of the most common upgrades performed by an A+ technician.
內存的用途之一是充當磁盤緩存。就像我們在處理器中提到的緩存一樣，RAM充當了硬盤驅動器中最近使用和常用數據的更快的臨時存儲區域。由於訪問RAM比查找硬盤驅動器扇區中的數據更快，因此RAM可提高計算機的性能。僅當內存中有可用空間時才可以使用磁盤緩存。但是，如果您沒有足夠的物理內存可用怎麼辦？當物理內存不足時，計算機將創建虛擬內存。虛擬內存有時也稱為“頁面文件”或“交換文件”。虛擬內存是RAM的慢速替代品，因為它是在硬盤驅動器上創建的臨時文件，並模擬物理RAM。本質上，磁盤緩存使RAM可以充當極快的硬盤驅動器，而虛擬內存由硬盤驅動器上的文件組成，它們的運行速度非常慢。 RAM比磁性存儲（如硬盤驅動器和軟盤）或光學存儲（DVD，CD，藍光）快。這是因為RAM是固態設備，訪問時間沒有特別長。 RAM的運行速度為十億分之一秒（十億分之一秒），而硬盤驅動器和其他磁性介質的運行速度非常慢，其運行速度為千分之一秒（毫秒）。 RAM不足會導致計算機運行更慢。因此，升級RAM是A +技術人員執行的最常見的升級之一。
PCH6-RAM Basics <<
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