Retrotechtacular: The IBM 7070

If you think of IBM mainframe computers, you most likely are thinking of the iconic S/360 or the slightly newer S/370. But what about the 7070 from 1958? It had transistors! It didn’t, however, use binary. Instead, it was a decimal-architecture machine. You can see a lost video of the machine below.

It was originally slated to upgrade the older IBM 650 and 705 computers. However, it wasn’t compatible with either, so IBM had to roll out the IBM7080, which was compatible, at least, with the 705. Both machines could run 650 code via emulation.

Hardly a personal computer, this beast weighed over 23,000 pounds and cost a cool $813,000. Most companies leased it, though for a mere $17,400 a month. For that price, you got 5,000 words of core memory that could each hold ten decimal digits and a sign bit. The CPU ran at a stately 27 kHz. Hey, this was 1958, after all. One innovation was that card readers and printers connected to the computer through a “synchronizer” that buffered between the relatively fast CPU and the relatively slow devices.

The computer used 14,000 circuit cards containing around 30,000 germanium transistors and 22,000 germanium diodes. We imagine the power bill was worse than the monthly rent.

It seems the film’s audio isn’t present, but the modern narrator gives some context. If you like this old iron, don’t miss the video of the later IBM S/370 or learn how to use an 029 card punch.

10 thoughts on “Retrotechtacular: The IBM 7070

  1. I used to buy those paddle boards [minus the gold connectors] on canal street [NYC] back in the early 60’s.
    They were a treasure trove of parts.
    I would after stripping all the parts, countersink the pads on the solder side, mount my components on the former solder side and make new circuits via point to point wiring on the former component side.

  2. Oh, you have to do a story on the Control Data 7600. I worked on one, and it was quite the beast. Built in 1967, it was the super computer at the time, and had a clock speed of 54Mhz, 60 bit CPU, (5) 12 bit sub words. Just the CPU was the size of a cubicle, memory was (4) refrigerator sized cabinets. It took over 500KW to run.

  3. I don’t often see references to the 7070. This brought back memories to my first real job, an operator on one for an ins. co. No printer or card reader attached, only tape drivers. It had a companion 1401 with a tape drive for the slow peripherals.

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