How to rescue files from RAW file system external hard disk without data loss?

Is it possible to recover computer documents and videos from external hard disk with RAW file system error? Honestly, my Seagate USB hard disk used on my laptop was strangely asking to format when I tried to extract my left data there. The desktop computer also cannot read this external drive and reported it needed to be formatted due to RAW file system. What do you think about this? Is it still possible to recover data from this RAW file system USB hard disk before format? Does my searched data recovery software work in such case, like

icare-recovery.com/howto/external-hard-drive-raw-format-asking-to-reformat.html 

or piriform.com/recuva?

Wait for your answer. Thanks in advance!