SSD Challenges

1. Hash values may be different due to wear leveling.

2. Data recovery is very challenging.

3. Wear leveling and TRIM are your enemy.

Wear leveling (also written as wear levelling) is a technique[1] for prolonging the service life of some kinds of erasable 
computer storage media, such as flash memory, which is used in solid-state drives (SSDs) and USB flash drives, 
and phase change memory. There are several wear leveling mechanisms that provide varying levels of longevity enhancement 
in such memory systems

The term preemptive wear leveling (PWL) has been used by Western Digital to describe their preservation technique 
used on hard disk drives (HDDs) designed for storing audio and video data. However, HDDs generally are not wear-leveled devices.

A trim command (known as TRIM in the ATA command set, and UNMAP in the SCSI command set) allows an operating system to 
inform a solid-state drive (SSD) which blocks of data are no longer considered in use and can be wiped internally


--> ONE OF THE SOLUTION (doesn't work on 100%) <--

Write blockers are devices that allow acquisition of information on a drive without creating the possibility of accidentally 
damaging the drive contents. They do this by allowing read commands to pass but by blocking write commands, hence their name.

There are two ways to build a write-blocker: the blocker can allow all commands to pass from the computer to 
the drive except for those that are on a particular list. Alternatively, the blocker can specifically block 
the write commands and let everything else through. 

Image: https://bounga.id/sites/bounga.id/files/styles/extra_large_800x600/public/tableau-t6u-sas-forensic-bridge-write-blocker_0.PNG?itok=QKbd6ge8

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Równoważenie zużycia to wykorzystywanie różnych metod optymalizacji zapisu, pozwalających na wydłużanie czasu, 
przez który nośnik danych jest zdatny do użycia. Najczęściej jest ono stosowane w pamięciach flash - głównie dyskach SSD.
Pojęcie to jest również używane przez firmę Western Digital do opisu techniki konserwacji produkowanych przez 
nią dysków twardych, jednak w ogólności dyski nie są urządzeniami dobrze równoważącymi zużycie.