Both are hard disk partitions. What is the difference between C disk and D disk?

Reference resources   Are hard disk partitions C Plate and D What's the difference between disks ？ - cloud + Community - Tencent cloud

Why is the hard disk from C The disk begins ？

In the early days, the floppy drive occupied A、B Two drive letters , So the drive letter of the hard disk starts from C Start .C disc 、D These are DOS and Windows The concept of continuity , To facilitate the management of documents , stay Linux There is no “ Disk character ” This kind of thing .

                        

Mechanical hard disk C The disk has the highest performance

Once the partition of the mechanical hard disk is delimited ,C Plate and D The disk will correspond to some fixed positions on the hard disk , And the logical addresses of these locations correspond to the actual locations one by one .

                         

C The disc corresponds to the outer ring of the disc , This area is the fastest to read and write , It can help improve the read-write performance of the system disk . And correspondingly , Usually, the partition corresponding to the drive letter at the back is closer to the inner part of the disc , The reading and writing speed of this area is faster than C The disk is slow . Common software installation C disc , This is how the last drive letter is used for archiving and backup .

                                     

Drive letter and performance of SSD

Solid state drives are different from mechanical drives , No matter when C Plate and D The disk does not correspond to a specific flash memory particle or flash memory location . The picture below shows Toshiba TR200 960G Solid state drive disassembly , use TC58NC1010GSB Master control with Toshiba BiCS3 Flash memory .

                                       

The emergence of solid-state disk is later than mechanical disk , But it must adapt to the storage logic structure that has been designed for mechanical hard disk .NAND Flash in Toshiba 1987 When it was invented in, it had some features completely different from magnetic storage media ： It must be erased before writing （ Cannot directly overwrite write ）、 Erased units Block Than the reading and writing units Page Many times bigger .FTL The emergence of flash memory conversion layer is to make solid-state disk work in the way of mechanical hard disk .

                           

FTL The physical address of the actual data stored in the flash memory of the solid state disk is no longer always fixed . File overwrite write at the operating system level , Or the garbage collection and wear balance strategy in the operating system , Will cause the actual position of the data in the flash memory chip of the solid-state disk to move .

                          

in other words , Solid-state drive C Plate and D The disk does not correspond to a fixed flash location , In addition, there is no difference in the reading and writing speed of flash memory in different positions , The data is stored on a solid state disk C Plate or D The disc becomes less important .

                                     

From Toshiba TR200 960GB Of AS SSD Benchmark The speed measurement results can be seen , The performance of different drive letters is basically the same , The difference between the figures is within reasonable error . about TR200 960GB For this kind of large capacity solid state drive , You can divide multiple partitions as you used to do with mechanical disks , Facilitate the classification and management of documents .

                                    

Small capacity SSD should be used with caution

And the smaller capacity of solid-state disk （ Less than or equal to 240GB） It is not recommended that you divide multiple partitions .C Disk is the first letter in the hard disk , It usually exists as a system disk . System files 、 Sleep files and some underlying driver software can only exist in C In the middle of the plate . Small capacity solid state drives often encounter space crises , And once the zoning is done , The space allocation between different drive letters is more difficult , Too many partitions will increase the burden of file management , It violates the original intention of multiple partitions .

                      

You can also use Windows Of “ library ” The function replaces the partition drive letter to organize and manage personal documents . Of course , If conditions permit , A large capacity SSD is more comfortable than saving money . Now a Toshiba original factory 480GB The solid state is less than 400 block , Small capacity old SSD You can retire with peace of mind .