Meaning: Able to withstand attack. Synonyms: unassailable; unattackable; impregnable; inviolable; secure; strong. Context examples: an impregnable fortress / fortifications that made the frontier inviolable. Similar: invulnerable (immune to attack; impregnable)
Definition - What does Magnetic Disk mean? A magnetic disk is a storage device that uses a magnetization process to write, rewrite and access data. It is covered with a magnetic coating and stores data in the form of tracks, spots and sectors. Hard disks, zip disks and floppy disks are common examples of magnetic disks.
There are two basic types of disks: magnetic disks and optical disks. On magnetic disks, data is encoded as microscopic magnetized needles on the disk's surface. You can record and erase data on a magnetic disk any number of times, just as you can with a cassette tape.