The original File Stores had four hard drives each. These hard drives were large, fast, expensive and crude, weighing about a hundred pounds (40 kg) with 128 tracks and one head per track as in a drum memory. They contained backups for software and for fixed data (translations) but were not used in call processing. These file stores, a high maintenance item with pneumatic valves and other mechanical parts, were replaced in the 1980s with the 1A Attached Processor System (1AAPS) using the 3B20D Computer to provide access to the "1A File Store". The 1AAPS "1A File Store" is just a disk partition in the 3B20D Computer.