1. read幾多次都得, write就要好似以前CD-RW/DVD-RW咁, data只加唔減, 一係就full erase再由頭黎過, 唔好間 ...
KinChungE 發表於 2017-11-28 16:05 
CHING 你用CD-RW 呢個比喻不錯. 不過我會當佢係好似BACKUP TAPE 咁睇.
呢隻野只可以當以前backup tape 做"archive" D backup (daily or weekly even monthly) 不斷咁increment 上去. 到full 左8TB 要KEEP 就用第二隻. 或者loop 番轉頭.format 左佢再黎用過.
個"archive copy" 係offline 咁用法. 做完就detach 擺到要倒番出黎先read 過咁.
而一般性既backup copies 係online 既. sync or diff. 會overwrite 會加會減. maintain exact same copy of the primary master 呢D 就一定用番normal type HDD. 死也不用SMR |