The only built-in notebook SSD 256GB is really not afford to hurt, so I bought a mobile SSD hard drive, the less common of the largest software and learning software (STEAM) mounted on the top of it.
But when I installed OCTAVE (MATLAB open source alternative) I find that things are not so simple.
OCTAVE installation package is only 286MB, but when I install, takes up a little more than my 18G hard drive.
View the folder where the software file, find the "size" folder is displayed as 5.25GB, but space has reached 18.4GB
space than the size of the file itself is large due to the existence of a "cluster" of this concept, it is allocated to hold files the minimum amount of disk space. Even a single file and then a small, will take up a "cluster" in size. "Cluster" in Windows, also known as "allocation unit", as we have also format the hard disk when this option.
But why such a phenomenon only appears on my mobile hard disk, occupied on my internal hard disk space and file size or less of it?
Could that be because my mobile hard disk "cluster" too big reason it?
indeed. File system when my mobile hard disk factory is exFAT
Microsoft official default cluster size for different file system are described in detail:
https://support.microsoft.com/zh-cn/help/140365/default-cluster-size-for-ntfs-fat-and-exfat
You can see, the default cluster size of the hard disk 16TB following NTFS format is 4KB. For more than 32GB exFAT hard drive, the default cluster size is 128KB, which means that no matter how small the file, had to take up 128KB.
NTFS file system is a "journaling", it will erase a lot of work, it is possible to shorten the life of flash memory. exFAT format is suitable for flash file system, in order to solve such as FAT32 does not support 4G and larger files and launch.
SSD and now even mobile hard disk U disk larger than 32GB is already a very common. If you are like me, imagine SSD installed software to mobile hard disk or U disk, store a lot of small files, it is recommended to buy after reformatting, the cluster size to 4KB.
I had to first copy files out, the cluster size to 4KB When you format, then copy files back about 30GB per cent more of the available space before the final comparison, the effect is obvious.
ps copy can be used when factcopy this small software, can be unattended, the speed should be faster than Explorer.
Find useful, do not begrudge comment like share point oh, I hope you forgive me, have any questions please correct me to discuss.
