Q: Low level workings of Compact

[HarikalarKutusu]

Here are some Q:

1. I have some data that can be compressed to 10% of the original. How does it behave wrt disk fragmentation? Is it done in place (causing fragmentation) or does it create the compressed versions in another location on a HDD?
2. How do these compressed folders behave with defrag utilities? I've been using IOBit's Smart Defrag, and it started to behave sluggish, it stops at a place and continues some 5 minutes later. This might be related I think. So, if the defrag utility moves the data around, does it get uncompressed or as they are using low level disk access will the data be kept "compact"ed?

Any ideas / insights on these?

[Masamune3210]

It creates an alternate data stream and puts the compressed data into it, the system notices the compressed data stream and reads that in substitution of the actual file

If the defragger handles ADS's correctly, it will defrag them just as any other file. The compression is not removed so long as the defragger uses the system API calls to defrag and doesn't try to pull any of its own stunts like manually moving the file itself

[HarikalarKutusu]

Thank you for the clarification, it seems we will be OK with a current defrag utility.

[Cregrant]

Some defrag utilities I've tested just skip compressed data (hello Auslogics), but UltimateDefrag 6 claims to support compressed files and works well