file size fake

can i change the size of a file. i mean not by _chsize, but just faking the size so that explorer shows it to what ever we like, with out actually adding or removing contents to/from the file. like i learned how to change name, time , date, attributes, blah blah.. but am curious about this.

I doubt that explorer searches through all files to calculate the total size every time you open it , so it must be stored somewhere. If you find out, you can probably modify it in some way...

I doubt that explorer searches through all files to calculate the total size every time you open it , so it must be stored somewhere. If you find out, you can probably modify it in some way...

Maybe the FAT (file allocation table)?

Definatly the fat table - but the problem would be modifying it.

The only way to change the size of a file would be to change the EOC mark in the FAT. DOS counts the number of clusters every time you do a DIR as it goes through the cluster chains. There is an entry in the DIRENTRY structure that contains the size of the file, but if it does not match the cluster count, DOS will flag an error and Scandisk will have to fix it. However, if you move the EOC mark to a different cluster, and have each added cluster point to the next, you will change the size of the file since DOS counts up to the EOC mark. However, you would just be wasting disk space as the added clusters would be wasted space.

Each sector is 512 bytes and each cluster is mutliple sectors. So if you had 4 sectors per cluster you would be wasting 4*512 bytes if you moved the EOC mark by one cluster.