IBM 705

The IBM 705 was a first generation tube based computer. It was announced October, 1954, with deliveries in 1956. It was a character oriented machine, with 7 bit characters and 35 bit words (to fit 5 characters). 705 Model I came with storage for 20,000 characters and cost around $590,000. (1954 dollars, which is over 4 million in 2003 dollars). Model II came with 40,000 characters of storage and Model III had a whopping 80,000 characters of storage.

The 705 was the first commercial computer with core memory. The IBM 704 (announced in 1954) also had core memory, but was generally regarded as a scientific computer. The 705 succeeded the IBM 702, which used CRT memory. The arithmetic unit alone used 1,700 vacuum tubes. It could multiple two 10 digit numbers in only .0024 seconds.

The customer who bought this machine replaced the original IBM banner with their own. It was common in this machine's day for customers to put computers on display (in the "glass house"). The Gallery was outbid for an original 705 banner in an eBay auction February 2006.

The Gallery's 705 console lives again! For the first time in perhaps 35 years, some of the 705's neon lamps have come back to life. The Gallery has been testing circuitry to drive the high-voltage lamps from low-voltage modern microcontrollers. We will eventually display the 705 console in "working" order, using a 705 console training manual as a guide.

Can you help?

• The Gallery is searching for a copy of the IBM 705 Functional Characteristics manual.
• Do you have a great story to tell about this machine? Let us know and with your permission we'll publish it on this web page.

Below is a 705 operator console as shown in an original 1955 marketing brochure in The Gallery's collection.

Click below for a blueprint of a typical 705 configuration. Size is a bit of an illusion -- the CPU at lower left is over 6 feet tall!

Click below for a 705 "cheat sheet" code chart.

The 705 used mainly 8-tube pluggable modules for electronic logic. Below is a type 705 pluggable unit that is a little unusual in that the space for two of the tubes is instead populated with a relay.

Click below for a diagram out of a 705 operator training guide that contains hundreds of light configurations -- designed to test whether the operator can correctly diagnose the state of the machine.

In 1956, a marketing pamplet was produced commemorating the installations of the 500th 650 system and the 100th 700 series system. The pamphlet has the following photo of the 100th 700 series (a 705) installed at Standard Oil (Indiana) in Whiting, Indiana. Coincidentally, the IBM 1720 Control System operator and power panels in The Gallery's collection (one of only three 1720's produced) is also from Standard Oil in Whiting.

A Message From the Original Operator of this Machine!

Hi,

My name is Carl Bannister and I was most surprised to receive a picture of the 705 console from your web page. It immediately brought back many memories especially with the Confederation Life name displayed across the top left side. I worked for Confed for 38 years starting in Feb.1955.

I was fortunate enough to be asked to take an aptitude test to become an operator on the soon to be installed wonder machine. I say fortunate because everyone was trying to get in on the action with this great new computer. You see, very few of the staff really had any idea of what this machine would do since it was entirely new to the general public. I guess the company had done a great job of promoting this entirely new method of doing business and there was a great deal of interest in it.

I went through the 5 wks.programming course in late 1957 and in mid July 1958 I became the first "Operator" of the new 705. I spent many frustrating hours seated in front of the console which you displayed. I have often wondered what became of this unit as it was still in storage when I retired in 1993 and with the demise of the company in 1994 I thought it was probably scrapped. It's nice to know it is still in existence. Your web page states that it was a model 1, but in fact it was a model 2 since the CPU had 40,000 memory positions.

Confed was the first financial institution in Canada to instal a 705. I mentioned the frustration involved in operating this large scale machine because to a very large extent Confed was pioneering in this new field and there were no resources outside of IBM from which to draw upon their experience. As a result we had to proceed on a trial and error basis to some extent in the very early stages of operation. However, with experience and perseverance things began to take shape and the 705 became a real success story.

Carl

And a Message from Don Harris!

The link to your web site was forwarded to some members of the "retired" and "formerly employed" IBM'ers in Nashville. A couple of the pages really brought back memories... all good.

Soon after arriving in Nashville after graduation from Clemson University in July 1967, I was assigned as a CE to Genesco (General Shoe Company). What an experience! We had a 705, a couple of 1400 series computers, 360/20, 360/50, rooms full of keypunches and verifiers, and several tab machines that I can't remember the numbers of as well as an old Univac system roughly the same size/capability as the 360/20. I wasn't trained on any of the equipment, but it became my job to keep all the tape drives functional.

I believe the 360's used 729 tapes and the 705 used 727 tapes. 90% of my job consisted of a constant repetition of PM for the ~30 drives in house. With three clutches per reel shaft on the 727's, rebuilding them was an everyday job it seemed. I did manage to help with the 705 on occasion. If we had a failure on it, we'd just turn the room lights out and look for a vacuum tube filament not on. I was told soon after arriving in Nashville that there were only three 705's remaining in production east of the Mississippi river and all three were in Nashville; one at Genesco and two at National Life and Accident Insurance Co.

Thanks for bringing back these memories for me.
Don Harris

Customer Engineering Education Material

The Gallery has been fortunate in finding very rare customer engineering education material for the 702-705 macines. We have a 22-ring binder containing:

• 702-705 Component Circuits, Form 29-9222-0, 1956, 182 pages.
• 705 Core Storage, Form 29-9222-0, 1956, 85 pages.
• 734 Magnetic Drum Storage, Form 29-9221-0, 1956, 52 pages.

The following are a few selected pages of customer engineer education material.

See other 705 related documents in the Gallery's Archives.