❶ 請問硬碟是靠什麼東西來儲存文件的
分類: 電腦/網路 >> 硬體
解析:
硬碟驅動器
是一種採用磁介質的數據存儲設備，數據存儲在密封於潔凈的硬碟驅動器內腔的若干個磁碟片上。這些碟片一般是在以鋁為主要成分的片基表面塗上磁性介質所形成，在磁碟片的每一面上，以轉動軸為軸心、以一定的磁密度為間隔的若干個同心圓就被劃分成磁軌（track），每個磁軌又被劃分為若干個扇區（sector），數據就按扇區存放在硬碟上。說起來，硬碟的工作原理很簡單，硬碟可以讀取和寫入保存數據，寫入數據實際上是通過磁頭對硬碟片表面的可磁化單元進行磁化，就象錄音機的錄音過程；不同的是，錄音機是將模擬信號順序地錄制在塗有磁介質的磁帶上，而硬碟是將二進制的數字信號以環狀同心圓軌跡的形式，一圈一圈地記錄在塗有磁介質的高速旋轉的盤面上。讀取數據時，只需把磁頭移動到相應的位置讀取此處的磁化編碼狀態即可。
❷ 文件越來越多，電腦磁碟儲存空間不足應該怎麼辦
伴隨系統逐漸運行，許多系統文件、備份文件、緩存文件等。用戶通過幾種途徑清理存儲空間，提升存儲空間。下面小編介紹一下硬碟存儲空間不足的解決辦法。
三、程序卸載或轉移
有些程序佔用存儲空間很大，平常用戶使用概率低，甚至幾乎用不到。用戶直接卸載長期用不到的程序，一些使用次數不多程序轉移到其他盤上，從而釋放出不少空間。徹底卸載電腦程序，用戶最好使用第三方軟體，將系統配置文件和備份文件一起刪除。軟體管理獨立版、驅動人生軟體管家、新毒霸管理軟體、網路管理軟體等都是不錯電腦管理軟體。這些軟體功能強大，靈活管理安裝應用程序，快捷安裝和升級、卸載，還推薦軟體下載。
❸ 長期存儲文件用固態還是機械
長期存儲文件用固態硬碟還是機械硬碟，主要取決於你的實際需求。
固態硬碟（SSD）和機械硬碟（HDD）都有各自的優勢和缺點，所以在選擇硬碟時需要根據自己的實際情況來選擇。
固態硬碟具有較高的讀取速度，能夠更快的打開文件和啟動電腦，而機械硬碟的優勢在於它的容量大，可以存儲更多的文件，彎胡也更便宜。
如果你想存儲大量的文件，並且不會經常使用這些文件嫌畢，且不對速度有較高要求，那麼機械硬碟更適合你。而如果你想要快速訪問文件，那麼固態硬碟就更適合你。
固態硬碟和機械硬碟都有各自的優勢，如果准確地判斷出自己的需求，就可以根據需求作出正確的選芹鬧芹擇，來滿足長期存儲文件的需求。
❹ 2020-12-02 硬碟如何存儲文件
系統中所有內容是以文件（文件夾是特殊的文件）存在的，而文件分為屬性（元信息）和內容兩部分，磁碟一部分被操作系統虛擬為塊用來存儲數據，同時也分出一部分虛擬為Inode用來存儲文件屬性，這樣磁碟就分為塊區和inode區。
扇區：磁碟存儲數據的最小物理單元，每個扇區很小512位元組左右。
讀取數據：OS要想讀取磁碟數據，首先讓磁頭徑向尋道（最慢），然後旋轉磁碟（較快），使磁頭到達目標扇區，開始讀取數據。
磁碟塊：OS日常工作中，一個扇區的512位元組數據很小，不足以支撐絕大部分工作場景，所以需要頻繁讀取單個扇區，而磁碟讀取數據速度相對CPU處理太慢了，所以讀磁碟時一次就多拿出幾個扇區（臨近的，無需耗費額外時間）的數據，於是在OS層面邏輯虛擬出磁碟塊（簇）的概念，一個磁碟塊一般對應8個連續扇區（也可4、16個等，由OS決定），這樣OS層面就使用磁碟塊作為最小數據存儲單元。
這樣的好處當然是更高效，缺點則是會？
inode：用於存儲文件的元信息（除名稱外的所有屬性，名稱存在文件夾的內容中）
Inode number is also known as index number. An inode is a unique number assigned to files and directories while it is created. The inode number will be unique to entire filesystem.
Disk inodes contain the following information:
Owner identifier
Type of file (regular, directory, character or block device)
Access permissions
Times and dates
· file creation time
· last file access time
· last inode modification time
Number of links to the file
Array of pointers to data blocks on disk
File size (in bytes, sometimes also in blocks)
文件：
上文提及文件屬性存在磁碟inode區的inode（每個都有編號）內，而內容存儲在塊區的塊中。
文件夾：
作為特殊文件，其組織文件及目錄，屬性也是存在inode內，而存儲的內容是一個包含多個{ 文件名:對應inode Id} 的列表，內容亦存在塊區的塊中。
這樣在OS中查看一個文件（比如/etc/fstab）的內容，大概是：
首先OS獲取到根目錄的inodeId >在inode區中讀取到其屬性（某項是內容所在塊）>在塊區讀取到根目錄內容>在內容中找到名為/etc對應發inodeId>/etc在inode區的屬性>讀取到塊中/etc的內容（包含/etc/fstab對應inodeId）>/etc/fstab Inode Id > 在inode區讀取到/etc/fstab屬性 >/etc/fstab塊。
可能有誤，望指點。
Within each file system, the mapping from names to blocks is handled through a structure called an i-node. There's a pool of these things near the "bottom" (lowest-numbered blocks) of each file system (the very lowest ones are used for housekeeping and labeling purposes we won't describe here). Each i-node describes one file. File data blocks (including directories) live above the i-nodes (in higher-numbered blocks).
Every i-node contains a list of the disk block numbers in the file it describes. (Actually this is a half-truth, only correct for small files, but the rest of the details aren't important here.) Note that the i-node does not contain the name of the file.
Names of files live in directory structures. A directory structure just maps names to i-node numbers. This is why, in Unix, a file can have multiple true names (or hard links); they're just multiple directory entries that happen to point to the same i-node.
refer: https://unix.stackexchange.com/questions/432655/why-does-using-indirect-pointers-in-inodes-not-incur-the-same-amount-of-space
less:by direct list blocks in node?.
large :by two-level indirect block
larger : multi-level indirect block.
The original hierarchy of the inodes levels works roughly like this:
You can store one or a few block numbers directly in the inode. This means you use a few bytes more for the inode, but for small files, you don't have to allocate a complete block, which is mostly empty.
The next level is one indirection: You allocate a block to store the block pointers. Only the address of this indirect block is stored in the inode. This doesn't use somehow "less space", and most filesystems, even early ones, worked like that (have a pointer near the inode/filename which points to a block, which stores the block numbers of the file).
But what do you do when the space in this block runs out? You have to allocate another block, but where do you store the reference to this block? You could just add those references to the inode, but to store largers files, the inode would get large. And you want small inodes, so as many as possible inodes can fit into a single block (less disk access to read more inodes).
So you use a two-level indirect block: You just add one pointer to the inode, then you have a whole block to store pointers to indirect blocks, and the indirect blocks store the block address of the file itself.
And so on, you can add higher-level indirect blocks, or stop at some stage, until you reach the maximal size of a file possible with the structure you want.
So the point is not "use up less space in total", but "use a scheme that uses blocks efficiently for the expected distribution a files wrt. to size, i.e. many small files, some larger files, and very few huge files".
Page tables on the other hand work very differently.
Edit
To answer the questions in the comment:
Data blocks are of fixed sizes (originally 512 bytes, IIRC), which is a multiple of the block size of the underlying harddisks. So data block size can't "decrease".
As I tried to describe above, the whole point of having the inodes not use up too much space is to make inode access faster (or, alternatively, make caching inodes use up less memory - back then when the unix file system with inodes was invented, computers had a lot less memory than today). It's not about somehow saving space in total. As you say yourself, everything has to be stored somewhere, and if it doesn't use up space at location X, it will use up space at location Y.
Just adding a variable number of block pointers to the inode is not practical, because the inode must take up a fixed amount of space - you want to use the inode number to calculate the block address and the offset inside the block where the inode information is stored. You can't do that if every inode has a different size. So there must be some form of indirection.
Page tables work differently because hardware implements them differently - that's just how it is. The hierarchy has a fixed depth, always the same (though sometimes configurable. And while reading a block from disk is slow, that doesn't matter for page tables. So the design issues are completely different.
http://www.cems.uwe.ac.uk/~irjohnso/coursenotes/lrc/internals/filestore/fs3.htm
Assuming, for the purposes of illustration, that each disk data block is 1024 bytes in size, then these ten data block pointers will allow files to be created that are up to 10 Kb in size. As you can see, for the large majority of files it should be possible to access the data with nothing more than a direct lookup required to find the data block that contains any particular data byte.
With this scheme, once a file has grown to 10 Kb, there are only three block pointers in the inode left to use, whatever the eventual size of the file. Obviously, some new arrangement must be found so that the three remaining block pointers will suffice for any realistic file size, while at the same time not degrading the data access time too much.
This goal is achieved by using the idea of indirect block pointers. Specifically, when an 11th data block needs to be allocated to the file, the 11th inode block pointer is used, but instead of pointing to the block which will contain the data, the 11th pointer is a single indirect pointer which points to a data block filled with a list of direct block pointers. In our example, if we assume that a data block number is a 32-bit value, then a list of 256 of them will fit into the single indirect block. This list will point directly to the data blocks for the next 256 Kb of our file. This means that with 11 block pointers in the inode, files of up to 266 Kb (10 + 256) can be created. True, it takes a little longer to access the data beyond the first 10 Kb in the file, but it takes only one extra disk block read to find the position on the disk of the required data.
For files bigger than 266 Kb the double indirect (12th) inode block pointer is used. This is the same idea as the previous inode pointer except that the double indirect pointer points to a list of pointers in a data block, each of which is itself a single indirect block pointer which points to a list of 256 direct block pointers. This means that the 12th inode block pointer gives access to the next 65536 Kb (256x256) of data in our file.
By now, you should be able to spot the pattern and see that when the file grows bigger than 64 Mb (actually 65802 Kb), the inode's 13th data block pointer will be used, but this time as a triple indirect pointer, which will give access to a staggering 16 Gb (256x256x256 Kb) of extra file space. A single file bigger than 16Gb sounds huge. However, even though the calculation we have just done suggests that this file size is possible with the inode layout as given, in fact there are other factors which limit the maximum size of a file to a smaller value than this. For example, the size of a file, in bytes, is stored separately in its inode in a field of type unsigned long. This is a 32-bit number which limits the size of a file to 4 Gb, so that 13 data block pointers in an inode really are enough.
10.4. How a file gets looked up
Now we can look at the file system from the top down. When you open a file (such as, say, /home/esr/WWW/ldp/fundamentals.xml) here is what happens:
Your kernel starts at the root of your Unix file system (in the root partition). It looks for a directory there called 『home』. Usually 『home』 is a mount point to a large user partition elsewhere, so it will go there. In the top-level directory structure of that user partition, it will look for a entry called 『esr』 and extract an i-node number. It will go to that i-node, notice that its associated file data blocks are a directory structure, and look up 『WWW』. Extracting that i-node, it will go to the corresponding subdirectory and look up 『ldp』. That will take it to yet another directory i-node. Opening that one, it will find an i-node number for 『fundamentals.xml』. That i-node is not a directory, but instead holds the list of disk blocks associated with the file.
The surface area of your disk, where it stores data, is divided up something like a dartboard — into circular tracks which are then pie-sliced into sectors. Because tracks near the outer edge have more area than those close to the spindle at the center of the disk, the outer tracks have more sector slices in them than the inner ones. Each sector (or disk block ) has the same size, which under modern Unixes is generally 1 binary K (1024 8-bit bytes). Each disk block has a unique address or disk block number .
Unix divides the disk into disk partitions . Each partition is a continuous span of blocks that's used separately from any other partition, either as a file system or as swap space. The original reasons for partitions had to do with crash recovery in a world of much slower and more error-prone disks; the boundaries between them rece the fraction of your disk likely to become inaccessible or corrupted by a random bad spot on the disk. Nowadays, it's more important that partitions can be declared read-only (preventing an intruder from modifying critical system files) or shared over a network through various means we won't discuss here. The lowest-numbered partition on a disk is often treated specially, as a boot partition where you can put a kernel to be booted.
Each partition is either swap space (used to implement virtual memory ) or a file system used to hold files. Swap-space partitions are just treated as a linear sequence of blocks. File systems, on the other hand, need a way to map file names to sequences of disk blocks. Because files grow, shrink, and change over time, a file's data blocks will not be a linear sequence but may be scattered all over its partition (from wherever the operating system can find a free block when it needs one). This scattering effect is called fragmentation .
Within each file system, the mapping from names to blocks is handled through a structure called an i-node . There's a pool of these things near the "bottom" (lowest-numbered blocks) of each file system (the very lowest ones are used for housekeeping and labeling purposes we won't describe here). Each i-node describes one file. File data blocks (including directories) live above the i-nodes (in higher-numbered blocks).
Every i-node contains a list of the disk block numbers in the file it describes. (Actually this is a half-truth, only correct for small files, but the rest of the details aren't important here.) Note that the i-node does not contain the name of the file.
Names of files live in directory structures . A directory structure just maps names to i-node numbers. This is why, in Unix, a file can have multiple true names (or hard links ); they're just multiple directory entries that happen to point to the same i-node.
In the simplest case, your entire Unix file system lives in just one disk partition. While you'll see this arrangement on some small personal Unix systems, it's unusual. More typical is for it to be spread across several disk partitions, possibly on different physical disks. So, for example, your system may have one small partition where the kernel lives, a slightly larger one where OS utilities live, and a much bigger one where user home directories live.
The only partition you'll have access to immediately after system boot is your root partition , which is (almost always) the one you booted from. It holds the root directory of the file system, the top node from which everything else hangs.
The other partitions in the system have to be attached to this root in order for your entire, multiple-partition file system to be accessible. About midway through the boot process, your Unix will make these non-root partitions accessible. It will mount each one onto a directory on the root partition.
For example, if you have a Unix directory called <tt class="filename">/usr</tt>, it is probably a mount point to a partition that contains many programs installed with your Unix but not required ring initial boot.
❺ 永久儲存資料用什麼硬碟好
永久儲存資料用機械硬碟好。
機械硬碟其實也是用磁來記錄信息，那就決定了機械硬碟的可修復性比較高，還有就是機械硬碟在不通電的情況下也能把數據保存十年以上，這就非常的適合長期保存數據了，而且相對固態硬碟來說便宜很多，買一個現成的移動硬碟即可。
硬碟介紹
電腦硬碟是計算機最主要的存儲設備。硬碟（港台稱之為硬碟，英文名：Hard Disk Drive， 簡稱HDD，全名溫徹斯特式硬碟）由一個或者多個鋁制或者玻璃制的碟片組成。這些碟片外覆蓋有鐵磁性材料。
絕大多數硬碟都是固定硬碟，被永久性地密封固定在硬碟驅動器中。早期的硬碟存儲媒介是可替換的，不過今日典型的硬碟是固定的存儲媒介，被封在硬碟里 （除了一個過濾孔，用來平衡空氣壓力）。
隨著發展，可移動硬碟也出現了，而且越來越普及，種類也越來越多.大多數微機上安裝的硬碟，由於都採用溫切斯特（winchester）技術而被稱之為「溫切斯特硬碟」，或簡稱「溫盤」。作為計算機系統的數據存儲器，容量是硬碟最主要的參數。