In early 1957, I saw my
first computer during a high-school field trip to an IBM office in
Cleveland, Ohio. It was a vacuum-tube mainframe in the IBM
700 series. Though I can find no record of that particular
IBM office, its mainframe was most probably an IBM
705 Data Processing System, which had been designed to
process business data.
The office was a single, large, street-level room that combined a
reception area and a data-processing workspace. An IBM employee,
probably an office manager, gave us his 'grand tour,' which was
lecturing to us while we stood in the center of the room. The
equipment included an operator's station, a large card punch and
reader, and a few cabinets for tape drives and power supplies.
Through a glass wall, we could see multiple racks of glowing vacuum
tubes in the back room.
Each IBM 700 series mainframe included a vacuum-tube processor, a
magnetic-core memory and data-storage devices for punched cards and
magnetic tape.
Vacuum-tube processor
A vacuum-tube processor in an IBM 700 series mainframe was roughly
similar to the CPU in a modern PC. This processor executed program
instructions, performed calculations, and communicated with
magnetic-core memory and data-storage devices.
I had recently seen a classmate's transistor radio. Therefore, at the
end of our host's 'sermon,' I asked him whether IBM would ever use
transistors in its computers. He said, "No," and explained
that transistors could never work as quickly as vacuum tubes.
Magnetic core memory
A magnetic-core
memory in an IBM 700 series mainframe was roughly similar
to RAM in a modern PC. This magnetic-core memory was the working
memory through which the processor made calculations. A magnetic-core
memory consisted of ferrite rings in a wired array, with three wires
threaded through each ring. Current pulsed simultaneously through two
wires would magnetize each ring in either of two directions (states),
on or off (1 or 0). The third wire would sense a change in state.
Data-storage devices
Each IBM 705 mainframe would use data-storage devices to store data
to, and retrieve it from, punched cards or magnetic tape. A business
customer would use cards or tape to bring its payroll, or other
business-operation data, to the IBM data center. After processing
these data through its mainframe, IBM would use cards or tape to send
the results to the customer.
Sources:
- Wikipedia, "IBM 700/7000 series", Wikipedia.org
- IBM Archives, "IBM 705 Data Processing System", IBM
- National High Magnetic Field Laboratory, "Magnetic Core Memory", Florida State University
