Notifications
Clear all

"logical size 0" vs 32 bytes in length.What exactly is this?

2 Posts
2 Users
0 Reactions
931 Views
(@yunus)
Estimable Member
Joined: 17 years ago
Posts: 178
Topic starter  

In a book about Encase, there are the following two sentences, which I thought might be contradictory. What do you think?

1. A directory entry in a FAT file system has no logical size.

2. Each directory entry in a FAT file system is 32 bytes in length.

If a directory entry is 32 bytes in length, it means it takes up a space of 32 bytes. So, What exactly do these sentences mean? How can a piece of data takes up a physical space of 32 byte but referred to having a size of 0 bytes?

Thanks.


   
Quote
(@mscotgrove)
Prominent Member
Joined: 17 years ago
Posts: 940
 

On a FAT32 system, the 32 byte directory entry gives the length of a file (max 32 bits, or 4GB). However, the pointer to a directory does not have a length, always set to 0. Thus what Encase is saying is correct.

A FAT directory will always be allocated in clusters,so a single entry will actually occupy at least one cluster, typically 8K or 16K. A sub directory also always starts with 2 entries, a . and .. entry pointint to itself, and the parent directory

The program has to calculate the directory length from the FAT.


   
ReplyQuote
Share: