Data Recovery Software thamai, HDD eken physically files delete wenne na, they just get overwritten. hithapan 1GB file ekak copy karanna 1-2 mins yanaa, delete karanna yanne 1-2 seconds. Reason is that on the HDD/SSD, the file is written on multiple sectors, all sectors are linked. Delete karanawa kiyanne file eke first sector eke mark wenawa deleted kiyala. Ethakota anith linked sectors become orphaned, ewa overwrite wenawa wena files copy weddi. Data recovery software eken karanne they identify the linked sectors and find the first one and mark it as non-deleted.
Disk defrag karoth data recovery chances henata adu wenawa. Eka nisa, if you wanna recover files, don't copy any files (specially large ones) and start the data recover process asap.