The first digital computers in the 1940s relied on slow and limited storage technologies like paper tape and punch cards. As computer processing advanced rapidly, the need for faster and higher capacity storage quickly became clear. This set the stage for a revolution in computer storage technology as engineers sought to develop improved storage devices that could keep pace with increasingly powerful computers.
As Tom Coughlin, an expert in digital storage technologies, wrote: “Storage is the beating heart of any computer system. And matching storage technology improvements to the equally fast-moving advances in processing and networking has always been a challenge.”
The First Hard Drive
The first hard drive was the IBM 350 RAMAC (Random Access Method of Accounting and Control), introduced in 1956. It was manufactured by IBM and had a storage capacity of 3.75 MB, extremely small by today’s standards. However, at the time it was considered groundbreaking and allowed random access to stored data for the first time.
The IBM 350 RAMAC consisted of fifty 24-inch disks coated with magnetic iron oxide, with 100 tracks per side. It could store over 5 million 7-bit characters, the equivalent of 64,000 punched cards. The disk rotated at 1200 RPM and data transfer speed was 8,800 characters per second.
To access the data, an access arm glided up and down to the desired disk, similar to how a record player needle accesses a specific track on a record. This electromechanical drive weighed over a ton and users leased the IBM 350 RAMAC for $3,200 per month, which equals over $10,000 per megabyte adjusted for inflation.
Sources:
https://www.historyofinformation.com/detail.php?entryid=952
https://en.wikipedia.org/wiki/History_of_hard_disk_drives
Magnetic Disk Storage
The first hard drive leveraged a type of storage media called magnetic disk storage. This technology relies on magnetizing a metal or metal alloy coating on a disk. The disk is flat and circular in shape with the magnetic coating on one or both sides. Data is written to the disk as magnetic transitions or changes in magnetization of the coating. Each magnetic transition is representative of binary data, either a 1 or a 0.
The disk spins rapidly while a read/write head floats slightly above the surface, allowing data to be magnetically recorded in tracks as the head moves radially across the disk. To retrieve the data, the read/write head passes over the tracks which induces an electrical signal based on the magnetic transitions. This signal is then decoded back into binary data. Magnetic disk storage allows direct, random access to data stored at any location. This provided a major speed advantage over previous sequential access storage like magnetic tape.
The first hard disk drive used a stack of metal disks coated with magnetic iron oxide, with multiple read/write heads that could access data on any disk surface (Recoverit). This multi-platter design increased storage capacity substantially compared to alternatives like magnetic drum storage. While initially very large, heavy and expensive, magnetic disk storage improved rapidly, enabling the rise of disk drives for personal and business computing.
Capacity
The RAMAC 350 had a total storage capacity of 3.75 megabytes spread across fifty 24-inch diameter disks spinning at 1,200 RPM.1 This was the equivalent of around 64,000 punch cards and a major leap in data capacity compared to previous magnetic drum memory which offered storage in the kilobytes. While small by today’s standards, the RAMAC’s 3.75 MB capacity was considered massive in 1956 and allowed businesses to store large databases that were previously impractical or only possible through rows of punched card files. The fifty disks provided an extremely high capacity storage system in a desk size device.
Size and Weight
The IBM 350 disk storage unit was massive in physical size. It stood over 5 feet tall and was more than 6 feet wide, taking up significant floor space. According to the Computer History Museum, the 350 disk storage system weighed over 1 ton. The considerable size and weight were largely due to the use of large disks that were 2 feet in diameter, as well as the components needed to spin them at high speeds.
To put the size in perspective, the IBM 350 was larger than modern commercial refrigerators. The unit had to be shipped on a freight truck and installed by a crew of technicians. The bulk of the system made it impractical for most businesses at the time. Only large organizations with extensive computer needs could accommodate it.
Cost
The IBM 305 RAMAC system was incredibly expensive when it was first introduced in 1956. According to the IBM Archives website, the RAMAC 305 leased for $3,200 per month, which equates to over $33,000 per month in 2022 dollars after adjusting for inflation.
To put this in perspective, the average US household income in 1956 was around $5,000 annually. So leasing the RAMAC would cost over half the average person’s yearly salary per month. This prohibitive pricing meant the RAMAC was only affordable to large corporations and government agencies.
According to the Computer History Museum, the total purchase price for one RAMAC unit with 350 disk storage was around $10,000 per megabyte in 1956 dollars (1). That works out to roughly $104,000 per megabyte today. By 1997, the cost had dropped dramatically to around $1 per megabyte of hard drive storage (1). So in just over 40 years, the price declined by a factor of 10,000 thanks to rapid innovation in storage technology.
Sources:
(1) https://www.historyofinformation.com/detail.php?entryid=952
Reliability
The RAMAC 350 was not without reliability issues in its early days. As one of the first commercial hard disk drives, it was breaking new ground in data storage technology. When it was first released in 1956, the disk packs had a reliability problem called “head crash” where the read/write heads would scrape against the disk surface, damaging the oxide coating and causing data loss (1). This was a common issue with early disk drives before technologies like air bearings were introduced to prevent head crashes.
IBM worked to improve the RAMAC 350’s reliability over time. Later models starting in the early 1960s incorporated more reliable disk pack designs to reduce head crashes. They also added redundant modules and other fault tolerance mechanisms to improve overall system reliability. By 1964, updated RAMAC drives were achieving average failure rates of only 60 per billion hours, which was considered excellent for that time period (2). So while the RAMAC 350 had some early reliability problems, IBM engineers progressively enhanced the technology to make it more dependable for business computing needs.
(1) https://www.computerhistory.org/revolution/memory-storage/8/233
(2) https://ed-thelen.org/RAMAC/Myths.html
Usage
The RAMAC was initially used by businesses for data processing and record keeping applications. In 1956, IBM launched the RAMAC along with a new business information processing system which marked the company’s entry into the data processing industry. The RAMAC allowed businesses to quickly access large amounts of stored information for applications like accounting, payroll, inventory management and more.
The RAMAC’s random access storage was revolutionary because previously data stored on punchcards, magnetic tape and other methods required sequential access – users had to go through the entire collection of data chronologically. The RAMAC’s disk storage allowed users to immediately retrieve any piece of data randomly, transforming how businesses could utilize computers for information management and data processing.
Some of the earliest customers of the RAMAC system included insurance companies, banks and railroads. They used the RAMAC for maintaining up-to-date records on policies, accounts, inventory and other critical business data. The RAMAC allowed much faster batched transaction processing compared to earlier electromechanical punched card systems.
Legacy
The IBM 350 RAMAC disk drive has an important place in the history of computer storage and technology. According to the Computer History Museum, the RAMAC 350 was the first disk drive and “much faster than existing punch card or magnetic tape storage methods.” Its introduction in 1956 marked a major milestone and paved the way for modern hard drives and data storage solutions.
Though its storage capacity was very small by today’s standards at around 5 MB, the RAMAC 350 had much greater flexibility and speed of access compared to previous storage mediums. As noted by ASME, this first commercial disk drive enabled random access to stored data for the first time, allowing computer systems to efficiently retrieve records non-sequentially. This capability opened new potential for data processing applications.
While tape drives and other storage technologies improved over time, the RAMAC 350’s basic design and use of rotating disk platters set the standard form factor for magnetic hard disk drives that followed. Later advances built upon the RAMAC legacy, including giant leaps in capacity and performance. But for its time, the RAMAC 350 represented a groundbreaking innovation, demonstrating the viability of random access disk storage and leading the way for the central role hard drives would come to play in computing.
Conclusion
The introduction of the first hard drive by IBM in 1956 marked a major milestone in computer data storage technology. Though extremely large, heavy, and expensive by today’s standards, the 350 RAMAC hard drive with its 5 MB storage capacity revolutionized the capabilities of early computers. For the first time, a practical magnetic disk storage device provided random access memory for large amounts of digital data.
While computer memory was previously constrained to limited magnetic drum or tape storage, the RAMAC hard drive enabled new applications with its relatively fast access speeds. By storing programs and data that could quickly be accessed and modified, it helped enable emerging business computing needs and new approaches to information management. Hard drives would continue to rapidly advance in capacity while shrinking in size and cost.
That original 5 MB RAMAC hard drive paved the way for the ubiquitous hard drives found in computers today with exponentially greater storage capacities. The development of magnetic disk storage enabled the digital information age as we know it.