Stored Computer Programs Part 1 Flashcards
What is a stored program computer (SPC) and what differed from earlier machines?
Computer that is able to erase the contents of the memory and store new data2 as well as program instructions in place of the old
How/who/where was the concept of a stored program computer developed?
Who: John Von Neumann
Where: The Moore School (the team that developed the ENIAC)
How: Came up with by people at Moore school as a follow up to the ENIAC (Eckert and Mauchly)
What are some important biographical events in the life of John von Neumann?
Age 6 could speak fluent greek
Age 8 mastered calculus
Age 19 publishing his own papers
At age 30 he was made the youngest member of the newly opened Institute for Advanced Study (IAS at Princeton).
What was the significance of the paper “The First Draft of a report on the EDVAC” and how was it related to the controversy over the development of the first SPC?
1945: “The First Draft of a Report on the EDVAC” gave him credit for stored computer program even though he didn’t come up with it
What was the significance of the seminar: “Theory and Techniques for the Design of Electronic Digital Computers”?
first showing of a conceptual spc to US and Britain.
What were the early memory technologies?
- Thermal memories
- Mechanical memories
- Delay line systems
- Electrostatic storage mechanisms
- Rotating magnetic memories
- Static magnetic memories
How did the two-level memory model work?
Had slow Ram like a magnetic drum and fast ram like a williams tube. Would load information from slow ram into the faster ram.
How did the early memory technologies work and what were their strengths/weaknesses?
Themal: Chalk covered drum that was heated. Wires would detect where it was heated. Fans would reset/clear memory by cooling registers down.
Mechanical: Used metal plates, but long term storage (didn’t really act as RAM). Mechanical pin memory, disk with holes and pin inserted into hole would determine which digit is stored. Brush would keep track of which hole had a pin. Way too slow as well
Delay: Mercury acoustic, essentially used a series of pulses as morse code. Then there would be a brief delay. Had to repeatedly do taps for long term storage. Electrical pulse recorded to sound using quartz crystal and mercury. Had receiver and emitter. getting good contact between mercury and quartz was a weakness and temperature was a weakness as well.
Electostatic: Williams Tube Used Vacuum Tubes. Essentially electron gun would shot through deflector and charge a cell for on and fuzzy state (semi-off).
Suffered read around problem where from firing 5 times per second electron gun would light up adjacent cells that weren’t supposed to be lit. Selectron was faster version of williams tube.
Rotating: Rotating magnet could record audio but was really slow with the drum. Booth’s magnetic drum was faster.
Static:
Was the memory successfully used in any of the early SPC and if so which ones?
- thermal was failure
- mechanical was failure
- Delay had widespread use
- Electrostatic first fast random access memory but replaced by rotating
- Rotating was used by some
When was the technology invented for the early memory technologies and put into use?
Themal: Mechanical: Delay: Electostatic: introduced 1946 completed 1948 Rotating: Static:
