Complex sentence: The ST-506 was the first 5.25 inch hard disk drive, introduced in 1980 by Seagate Technology (then Shugart Technology) It stored up to 5 megabytes after formatting and cost $1500.
Split into simpler sentences: The ST-506 was the first 5.25 inch hard disk drive. Introduced in 1980 by Seagate Technology (then Shugart Technology), it stored up to 5 megabytes after formatting and cost $1500.