On September 14, 1956, IBM publicly announced the RAMAC 305 system, built around the IBM 350 disk storage unit — the world’s first commercial hard disk drive. Two refrigerator-sized cabinets held 50 spinning magnetic platters that together stored about 5 megabytes, a staggering capacity for the time delivered by a machine that weighed over a ton and had to be moved by forklift.
What made RAMAC a turning point wasn’t just the storage size, it was the “random access” part of its name. Earlier computers relied on magnetic tape, which meant reading data in strict sequential order, like fast-forwarding a cassette to find one song. RAMAC’s disk heads could instead jump straight to any piece of data, which is the same basic principle underlying every hard drive and SSD in use today. Banks and insurers were early customers, using it for real-time accounting and inventory tracking rather than the batch-processed reports that had defined computing up to that point.
RAMAC’s reign at the top was short but its legacy was not: IBM kept building on the disk-drive concept for decades, and the RAMAC name is often cited as the true starting point of the data storage industry. A working RAMAC unit is preserved today at the Computer History Museum in Mountain View, California.
Source: Wikipedia — IBM 305 RAMAC
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