Usually when talking computer classics, I stick to computers from the 70s, 80s, and 90s. This video from IBM shows a state-of-the-art accounting computer from the 1950s. See how far we’ve come.


With a computer on almost every desk, it’s difficult to think of a time when business ran without computers at all. This is especially true when it comes to numbers-intensive business functions like accounting.  If you’ve ever taken an accounting class and had to do manual ledgers, you quickly realize how crazy it must have been tracking multi-million dollar businesses doing debits and credits by hand. No wonder Scrooge was always so cranky and worked Bob Cratchit so hard.

In the 1950’s computers were just starting to gain traction in business. IBM lead the charge with several units. One of the most popular is shown in the video above, the IBM 305 RAMAC.

State of the art computing circa 1956

IBM had been producing computers for some time by the time they developed the IBM 305 RAMAC. It launched in September 1956. The RAMAC was significant for the fact that it was one of the last IBM mainframes built around vacuum tubes.

The RAMAC included some things that are in modern computers, just in antiquated form. There were also things that are in modern computers that wouldn’t be developed for years. For example, the RAMAC included a hard drive, could drive a printer, and accepted input from a keyboard.  However, there was no monitor to interact with. All data was entered via punch card. There also was no such thing as a formal CPU as we know it today.

The RAMAC didn’t come cheap.  IBM leased it at a rate of $3200 per month, which is about $24,000 in today’s money. Among the customers IBM had for it were Chrysler and the 1960 Winter Olympics. IBM built over 1000 units between 1956 and 1961 when it was ultimately ended production.

Let’s go to the video

This video was a sales piece done by IBM touting the advances of the IBM 305 RAMAC. It starts off sounding like all of those science documentaries you ever saw while in elementary school. The presenter makes sure to point out the ‘beautiful design’ and compact size of the unit. Today you’d have more power in a handheld calculator, but for 1956 when computers filled entire rooms, this unit isn’t much bigger than a few cubicles, so it was a major advance.

The presenter takes time to point out the major features of the 305 RAMAC. Among them are the 50 platter disk drive which was standard for the unit.  As he points out, it could hold about 64000 punch cards worth of information.

He describes the drive as being able to store 5 million characters. This isn’t exactly equivalent to 5 Megabytes of information. These computers didn’t measure data in the standard 8-bit units we’re used to today.  Characters were built out of 7 bit units. Therefore, with a little bit of math, the 5 million character limit on the hard drive equates to 4.375 megabytes. Just a little more than 3 floppy disks.

The disk transfer rate was also slower than a modern floppy drive. It could only transfer 8800 characters per second. The minimum transfer rate on a 1.44 MB floppy controller is 500Kbps.

The 305 RAMAC doesn’t have anything like a modern CPU. Instead, the presenter discusses the Magnetic Process Drum which turns at 6000 RPM. This is where the work is done with the Magnetic Core Units assisting.

As the video continues, you see all of the mandatory blinking lights and knobs that were mandatory in computer design. You could see the spider’s nightmare of wires in the storage process units and other paces as well. I’m not sure how you were supposed to tell what was going on, but at least you knew something what happening with all the flashing lights I guess.

More information about the 305 RAMAC

IBM has rebuilt a couple of these units and you can still see them in action. The RAMAC Restoration Website includes lots of information about the 305 including copies of the original user’s manual, the engineer’s guide, and a plug wiring diagram.< –>