# A script/tool to check actual capacity without errors (aliexpress drive)

**URL:** <https://discourse.julialang.org/t/a-script-tool-to-check-actual-capacity-without-errors-aliexpress-drive/134884>\
**Category:** Offtopic\
**Created:** [January 5, 2026, 9:38am UTC](https://discourse.julialang.org/t/a-script-tool-to-check-actual-capacity-without-errors-aliexpress-drive/134884 "2026-01-05T09:38:37Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![sylvaticus](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/sylvaticus/32/203883_2.png) [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Post date:** [January 5, 2026, 9:38am UTC](https://discourse.julialang.org/t/a-script-tool-to-check-actual-capacity-without-errors-aliexpress-drive/134884/1 "2026-01-05T09:38:37Z")

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I have bought to my kid a “2TB” external drive on AliExpress, but I have now realized that it may just come with hacked firmware, so **I am looking for a tool to check the actual capacity of a mounted path without errors**.  
I am posting on “offtopic” because if such a tool already exists, all good, I am not going spend time on it:-)), but if it doesn’t exist, I am thinking to a Julia script that, provided with the path to lookup, the declared capacity and a `chunk_size`, would loop over the chunks, create random bits of `chunk_size`, cheksum the chunk, write it on the target path, and read back it **and all the previous chunks** in order to cheksum them back.  
This of course would lead to a trade-off on `chunk_size` between speed and practicability/accuracy..  
Also, perhaps you have a better idea (instead of random bits, use some sequence that has computable check-sum or that can be sampled in reading???)…

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**Author:** ![cjdoris](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/cjdoris/32/213133_2.png) [@cjdoris](https://discourse.julialang.org/u/cjdoris)\
**Post date:** [January 5, 2026, 9:59am UTC](https://discourse.julialang.org/t/a-script-tool-to-check-actual-capacity-without-errors-aliexpress-drive/134884/2 "2026-01-05T09:59:16Z")

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I’d write 2000 x 1GB files to the disk, containing pseudo-random data. Then read each file back and check it equals what you expect by generating the same pseudo-random data again. Count how many match. No checksums required.

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**Author:** ![sylvaticus](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/sylvaticus/32/203883_2.png) [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Post date:** [January 5, 2026, 10:35am UTC](https://discourse.julialang.org/t/a-script-tool-to-check-actual-capacity-without-errors-aliexpress-drive/134884/3 "2026-01-05T10:35:07Z")

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Of course it seems that such tools are already widely used, e.g. “f3” (“Fight Flash Fraud”, or “Fight Fake Flash”).. there are always new things to learn…

> **[F3 by Digirati](https://oss.digirati.com.br/f3/)**

[https://www.grc.com/validrive.htm](https://www.grc.com/validrive.htm)