First of all the term fragmentation cues there's an entity divided into parts — fragments.
Internal fragmentation: Typical paper book is a collection of pages (text divided into pages). When a chapter's end isn't located at the end of page and new chapter starts from new page, there's a gap between those chapters and it's a waste of space — a chunk (page for a book) has unused space inside (internally) — "white space"
External fragmentation: Say you have a paper diary and you didn't write your thoughts sequentially page after page, but, rather randomly. You might end up with a situation when you'd want to write 3 pages in row, but you can't since there're no 3 clean pages one-by-one, you might have 15 clean pages in the diary totally, but they're not contiguous
I am an operating system that only allocates you memory in 10mb partitions.
Internal Fragmentation
You ask for 17mb of memory
I give you 20mb of memory
Fulfilling this request has just led to 3mb of internal fragmentation.
External Fragmentation
You ask for 20mb of memory
I give you 20mb of memory
The 20mb of memory that I give you is not immediately contiguous next to another existing piece of allocated memory. In so handing you this memory, I have "split" a single unallocated space into two spaces.
Fulfilling this request has just led to external fragmentation
Internal Fragmentation Internal fragmentation occurs when the memory allocator leaves extra space empty inside of a block of memory that has been allocated for a client. This usually happens because the processor’s design stipulates that memory must be cut into blocks of certain sizes -- for example, blocks may be required to be evenly be divided by four, eight or 16 bytes. When this occurs, a client that needs 57 bytes of memory, for example, may be allocated a block that contains 60 bytes, or even 64. The extra bytes that the client doesn’t need go to waste, and over time these tiny chunks of unused memory can build up and create large quantities of memory that can’t be put to use by the allocator. Because all of these useless bytes are inside larger memory blocks, the fragmentation is considered internal.
External Fragmentation External fragmentation happens when the memory allocator leaves sections of unused memory blocks between portions of allocated memory. For example, if several memory blocks are allocated in a continuous line but one of the middle blocks in the line is freed (perhaps because the process that was using that block of memory stopped running), the free block is fragmented. The block is still available for use by the allocator later if there’s a need for memory that fits in that block, but the block is now unusable for larger memory needs. It cannot be lumped back in with the total free memory available to the system, as total memory must be contiguous for it to be useable for larger tasks. In this way, entire sections of free memory can end up isolated from the whole that are often too small for significant use, which creates an overall reduction of free memory that over time can lead to a lack of available memory for key tasks.
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外部碎片
总内存空间足以满足请求或在其中驻留进程，但它不是连续的，因此无法使用。
内部碎片
分配给进程的内存块更大。 内存的某些部分未被使用，因为它不能被其他进程使用。
External fragmentation
Total memory space is enough to satisfy a request or to reside a process in it, but it is not contiguous so it can not be used.
Internal fragmentation
Memory block assigned to process is bigger. Some portion of memory is left unused as it can not be used by another process.
首先，术语碎片暗示存在一个被分成多个部分的实体——碎片。
内部碎片：典型的纸质书是页面的集合（文本分为页面）。 当一章的结尾不在页面的末尾并且新的章节从新的页面开始时，这些章节之间存在间隙，这是空间的浪费 - 一个块（一本书的页面）内部有未使用的空间 /em> (内部) —“空白”
外部碎片：假设你有一本纸质日记，但你没有一页一页地按顺序写下你的想法，但是，相当随机。 你可能会遇到这样的情况：你想连续写 3 页，但你不能，因为没有 3 页一页一页的干净页，你的日记中可能总共有 15 页干净页，但是它们不连续
First of all the term fragmentation cues there's an entity divided into parts — fragments.
Internal fragmentation: Typical paper book is a collection of pages (text divided into pages). When a chapter's end isn't located at the end of page and new chapter starts from new page, there's a gap between those chapters and it's a waste of space — a chunk (page for a book) has unused space inside (internally) — "white space"
External fragmentation: Say you have a paper diary and you didn't write your thoughts sequentially page after page, but, rather randomly. You might end up with a situation when you'd want to write 3 pages in row, but you can't since there're no 3 clean pages one-by-one, you might have 15 clean pages in the diary totally, but they're not contiguous
我是一个只在 10mb 分区中分配内存的操作系统。
内部碎片
满足此请求只会导致 3mb 内部碎片。
外部碎片
满足这个请求刚刚导致了外部碎片
I am an operating system that only allocates you memory in 10mb partitions.
Internal Fragmentation
Fulfilling this request has just led to 3mb of internal fragmentation.
External Fragmentation
Fulfilling this request has just led to external fragmentation
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