Large files MD5 unmatched (Data changeble?)

[kurukuru]

Hi.

If I copy large(1GB~) file from local PC to NAS(AS-604T),
there is a strong probability that two files(local and NAS) MD5(CRC16,CRC32) hash is unmatched.

For example... same one .RAR file about 1GB.
1. MD5=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX : original file in local
2. MD5=YYYYYYYYYYYYYYYYYYYYYYYYYYYYYY : copy from local to NAS by windwos explorer
3. MD5=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ : copy from local to NAS by ADM file explorer
4. MD5=AAAAAAAAAAAAAAAAAAAAAAAAAAAAA : copy from NAS to local by windows explorer
5. MD5=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX : repair case 4 file by recovery record
All of above file size is same size.
But values of MD5 are different each other.

Strange to say, if this file is movie, playing movie is no problem at all.
case 4:But if this is RAR file, extracting is failed, because I get the corrupt error(CRC error).
case 5:If I repair the RAR by recovery record, I can extract it completely.
But I have to spend more time for recovery, so I don't want to do this.

I think that if copy files are small size, this problem doesn't appear.

And I found similar problem in QNAP product.
http://www.excite-webtl.jp/world/englis ... wb_lp=JAEN
Above English is strange a little, because the page is output of automatic language translation, sorry.

Have you ever heard any reports like this?

Please, analysis this problem.

Thanks.

Condition
My local PC: Windows7 64bit edition
NAS: ASUSTOR AS-604T(ADM: 1.0.9.R661)
Browser for access ADM: Goggle Chrome
Network:
local PC---wireless (802.11n/g/b)---Buffalo router---100BaseTX---AS-604T

[Steve@AST]

Hi kurukuru,


I would like to reproduce your test at my site,but I have some question that I need you to clarify
please check the steps that I list below

File test.rar is in local PC and it's under folder "PC" in D drive

1. Copy test.rar from PC to NAS shared folder "Public" via Windows explorer (copy through SAMBA protocol,right?)
2. Upload test.rar from PC to NAS shared folder "Public1" via File Explorer (or should I put the file to "Public" and overwrite the same file?)
3. Download test.rar from NAS shared folder "Public" via Windows explorer (or should I overwrite the file in Local folder "PC")
4. What's your recovery record setting?

br.

Steve