A basic question - China DOS Union Forum - China DOS Union

It’s complicated to explain!
Sigh!
On a disk, besides the files we can see,
there is also the disk’s own file storage format,
otherwise how would we know where the files are stored on a round disk!
For example, FAT32 and NTFS are both basic disk formats.
A disk is divided into N sectors, and each sector
is further divided into
clusters one by one.
Files are split up and stored in each cluster.

And each cluster is used like this below:

ID address file ID address

We usually can’t see those identification files.
That’s also why a formatted disk is a bit smaller than an unformatted one.
A 1.44MB floppy disk, after being formatted, only has about 1.38MB left.
The missing space is taken up by these hidden identification files.

To put it more accurately, an image file means those identification files are copied too.
So naturally the file will be a bit larger.
But not entirely,
because image files can be compressed,
so some files on the disk that originally could not be compressed also get compressed, so naturally the space
becomes a bit smaller.
Another very important reason for having image files
is that some files are invisible, but you still can’t do without them.
For example, the boot sector on a boot disk cannot be seen.
If we don’t use an image,
and just simply copy the files on the disk over,
the copied boot disk will not be able to boot the computer,
because it is missing that boot sector!

Floor1　ricepot100	Posted 2003-05-18 00:00
初级用户　Posts 49　Credits 294
What is an image? What is a file image? A floppy disk image? My head is spinning. I’d only heard of it before, never really looked into what it was. Please help.

Floor2　沈洁	Posted 2003-05-18 00:00
金牌会员　Posts 1,812　Credits 4,590　From 上海市
It’s complicated to explain! Sigh! On a disk, besides the files we can see, there is also the disk’s own file storage format, otherwise how would we know where the files are stored on a round disk! For example, FAT32 and NTFS are both basic disk formats. A disk is divided into N sectors, and each sector is further divided into clusters one by one. Files are split up and stored in each cluster. And each cluster is used like this below: ID address file ID address We usually can’t see those identification files. That’s also why a formatted disk is a bit smaller than an unformatted one. A 1.44MB floppy disk, after being formatted, only has about 1.38MB left. The missing space is taken up by these hidden identification files. To put it more accurately, an image file means those identification files are copied too. So naturally the file will be a bit larger. But not entirely, because image files can be compressed, so some files on the disk that originally could not be compressed also get compressed, so naturally the space becomes a bit smaller. Another very important reason for having image files is that some files are invisible, but you still can’t do without them. For example, the boot sector on a boot disk cannot be seen. If we don’t use an image, and just simply copy the files on the disk over, the copied boot disk will not be able to boot the computer, because it is missing that boot sector!

Floor3　ricepot100	Posted 2003-05-18 00:00
初级用户　Posts 49　Credits 294
I’m really touched. Thanks, brother.

Floor4　tanglu_sd	Posted 2003-05-18 00:00
高级用户　Posts 271　Credits 948　From sd
If the original KV2003 or Rising 2003 key disk is made into an image disk and then restored, will it be exactly the same as the original disk? Can it also be used as a key disk? I tried it and it didn’t work. Why?

Floor5　hunome	Posted 2003-05-19 00:00
银牌会员　Posts 721　Credits 2,265
Because these disks are encrypted with special methods, normal methods only copy part of them!

Floor6　如是大师	Posted 2003-05-20 00:00
元老会员　Posts 3,351　Credits 9,654　From 湖北
Things like key disks have been tampered with at the floppy tracks, so normally copied files won’t work... But there is also special software for breaking floppy disk encryption........