Answer to guess what #1 of a series

-May 25, 2013

Good guesses this week to identify this item!

The image is a hard disk drive with only 5 MB of storage (we get 16 GB + nowadays in our USB memory sticks—that’s 3,200 of these 1956 hard drives!) The good news was that it replaced punch cards1---remember them? Prior to this magnetic computer storage had consisted of core memory, tape, and drums.

At NYU Engineering, at University Heights in the Bronx, in 1968 we used a Univac computer that filled an air-conditioned room and we had to use punch cards--God forbid you got your print-out back a day later with the words, “Fatal error” imprinted at the bottom! The process began all over again---find the error, re-type the punch cards, submit the box of punch cards to the operators and wait another day for your program results.

On September 13, 1956 IBM launched the 305 RAMAC, the first "SUPER" computer with a hard disk drive (HDD). The HDD weighed over 2,000 pounds and took up 16 square feet or floor space.

The IBM 305 RAMAC (Random Access Memory Accounting System) was an electronic general purpose data processing machine that maintained business records on a real-time basis. It was one of the last vacuum tube systems designed by IBM and the first computer with a hard drive, and more than 1,000 of them were built before production ended in 1961. It used the IBM 350 moving head hard drive, similar to the hard drives we still use today.

The following is compliments of

It was the first commercial computer to use a moving head hard disk drive, storing five million characters of accounting data, the equivalent of 64,000 punch cards, on 50 24" magnetic disks (Figure 2). To put it in today's terms, the colossal machine held about 5MB of data. Its magnetic disks were accessed by two arms, controlled by vacuum-tubes, that were noisily protected by compressed air.

Even with thse drawback, companies saw that there advantages to be reaped. The 305 RAMAC could handle a variety of input sources, including punch cards, and could store and access unprecedented amounts of data with incredible speed. It was also the first computer to offer random access to data, where previous storage tapes had to be run from start to finish to find the required piece of information. Compare the effort it takes to pinpoint a moment on a cassette tape to finding that same moment on a CD. Now think of that improvement in terms of the data accessed by every large corporation or governmental agency in the country. The 305 RAMAC was definitely a big deal back then.

Here's how IBM pitched the computer in 1956:

By the time production ended, in 1961, IBM had manufactured over 1,000 305 RAMACs, which had been leased to companies for $3,200 a month. But for those companies, it was worth it—the amount of data they could store and the speed with which they could access it was becoming increasingly important to their bottom lines. And it was their investments in the 1950s that pushed the development of hard drives like those found in the 305 RAMAC, shrinking them to the ones we use in our gadgets today.

The following is compliments of

Figure 1: The RAMAC in action had the disk drive named IBM 350 Disk File (The mystery photo in my Anablog) which can be seen in the picture at the left of the operator (Image compliments of

Figure 2: The magnetic disk was seen as a replacement for the magnetic drum for the same reason 78 RPM Records eventually replaced Edison cylinders- more storage with less space. (Image compliments of


The 350 Disk File, consisting of that stack of fifty 24" discs that can be seen to the left of the operator in the above picture in Figure 1. The capacity of the entire disk file was 5 million 7-bit characters, which works out to about 4.4 MB in modern parlance. This is about the same capacity as the first personal computer hard drives that appeared in the early 1980's, but was an enormous capacity for 1956. IBM leased the 350 Disk File for a $35,000 annual fee.

Today the magnetic disc is the platform of choice for the temporary storage of digital video, but it wasn't until the late 1960's that the magnetic disc was used for any sort of video storage. At that time the Instant Replay Deck was introduced, which permitted the storage and playback of brief segments of analog video.

We've certainly come a long way!

Do you feel that legacy features hold back new technologies? For the computers of the early 1950s, punch cards were a hundred-year old legacy feature. Though they were easily destroyed and largely inefficient, but they remained the predominant medium for data storage throughout the first half of the 20th century.

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