To the Moon on RAMs and ROMs

Hubble, probes to the planets etc

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brian livesey
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Joined: Mon Jan 09, 2006 11:05 am
Location: Lancashire

To the Moon on RAMs and ROMs

Post by brian livesey »

On this day in 1969, humanity's boot made first contact with the lunar surface. From an engineering point of view, the Apollo project was slide rule technology, with, by present day standards, only a modicum of computing power involved.
How did Apollo's computing power compare with that available now and at the "domestic" level? It was no match for smartphones and current pocket calculators, as Graham Kendal, professor of computer science at Nottingham University explains:-
"On board the craft that took Neil Armstrong, Buzz Aldrin and Mike Collins into space was a computer called the Apollo Guidance Computer with 32,768 bits of Random Access Memory (RAM) to store temporary results - data that are lost when there is no power.
The latest iPhones typically have 4GB of RAM - or 34, 359,738,368 bits. This is more than one million times more memory than the Apollo computer had in RAM."
"The spacecraft also had 72K of Read Only Memory (ROM). This memory is stored and cannot be changed once it is finalised. The iPhone has up to 512GB of ROM memory, seven million times more than that of the guidance computer. But memory isn't the only thing that matters. The Apollo 11 computer had a processor- an electronic circuit that performs operations on external data sources - which ran at 0.043 MHz. The latest iPhone's processor is estimated to run at about 2490 MHz. This means that it has over 1000,000 times the processing power than the computer that landed a man on the Moon 50 years ago."...
"How did the Apollo 11 computer compare against a classic calculator? Take the T-184 model, released by Texas Instruments in 2004. It had 32 times more RAM than the Apollo computer - and 14,500 times more ROM. With regard to processing speed, the TI-84 was almost 350 times faster"...
"One thing that is no better on today's space missions, even with our advances in technology, is the communication speed with Earth. The time it takes to communicate is the same as it was in 1969 - the speed of light - which means that it takes 1.26 seconds for a message to get from the Moon to the Earth. But with the larger files we now send - and from greater and greater distances - to get an image from a spacecraft to Earth today will take relatively longer than it did in 1969"...
"Acknowledging what it took to land people on the Moon in 1969 with the limited computing power that was available at the time, only makes the Apollo 11 mission an even more remarkable achievement."
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