# Archive Sector
An archive as it is stored: a chain of fixed size sectors scattered through the data file, still
compressed.

{ref}`TCacheIndex.ReadArchiveSector` walks that chain and hands back the bytes;
{ref}`TArchiveSector.Decompress` turns them into the archive's contents.


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## ArchiveSector.Create
```pascal
function TArchiveSector.Create(position, size: Integer; big: Boolean): TArchiveSector; static;
```
An empty sector chain of `size` bytes starting at `position` in the data file.

`big` marks an archive whose id needs 4 bytes rather than 2, which makes its sector headers two
bytes longer and leaves that much less room for data in each one.


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## ArchiveSector.Decompress
```pascal
function TArchiveSector.Decompress(): TByteArray;
```
The name of the function should be self explanatory, decompresses the compressed data in the
current archive sector.