EDSAC 2

{{short description|Early computer from 1958}}

{{Use dmy dates|date=April 2022}}

{{Infobox information appliance

| name = EDSAC 2

| image = EDSAC 2 1960.jpg

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| alt = Group of people in a room, gathered around a table with paper tape equipment.

| caption = EDSAC 2 users in 1960

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| developer = University of Cambridge, Mathematical Laboratory, UK

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| releasedate = {{Start date and age|1958}}

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| lifespan = Decommissioned 1965

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| input = 5-level paper tape, up to 1000 characters per second read, 300 cps punched output, two-out-of-five code

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| cpu = 20-bit instructions with 11-bit addresses, two index registers, microcoded;

| CPUspeed = fixed point add: 17–42 microseconds, floating point add: 100–170 microseconds

| storage = block-structured magnetic tape, 16K words, core memory, added in 1962

| memory = 1024 words RAM, 768 words ROM

| RAMtype = core memory, 40-bit words

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| predecessor = EDSAC

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}}

EDSAC 2 was an early vacuum tube computer (operational in 1958), the successor to the Electronic Delay Storage Automatic Calculator (EDSAC). It was the first computer to have a microprogrammed control unit and a bit-slice hardware architecture.{{Cite journal|last=Wilkes|first=M.V.|others=PDF available by "View PDF" (expand "View on IEEE")|s2cid=11377060|title=EDSAC 2|journal=IEEE Annals of the History of Computing|year=1992|language=en-US|volume=14|issue=4|pages=49–56|doi=10.1109/85.194055}}

File:EDSAC II chassis construction.jpg

First calculations were performed on the incomplete machine in 1957.{{Cite book|chapter-url=https://books.google.com/books?id=5461WiPV-eEC&q=EDSAC%20II%201957&pg=PA31|title=New Scientist|date=1957-08-08|publisher=Reed Business Information|pages=31|language=en|chapter=New computer in Cambridge}} Calculations about elliptic curves performed on EDSAC-2 in the early 1960s led to the Birch and Swinnerton-Dyer conjecture, a Millennium Prize Problem, unsolved as of 2024. And in 1963, Frederick Vine and Drummond Matthews used EDSAC 2 to generate a magnetic anomaly map of the seafloor from data collected in the Indian Ocean by H.M.S. Owen, key evidence that helped support the theory of plate tectonics.{{Cite journal| volume = 199| issue = 4897| pages = 947–949| last1 = Vine| first1 = Fred J.| last2 = Matthews| first2 = Drummond H.| title = Magnetic anomalies over oceanic ridges| journal = Nature | date = 1963| doi=10.1038/199947a0| bibcode = 1963Natur.199..947V| s2cid = 4296143}} EDSAC-2 was decommissioned in 1965, having been superseded by the Titan computer.{{Cite web |title=EDSAC II Arithmetic Unit – Computer | publisher=Computing History | url=https://www.computinghistory.org.uk/det/11977/EDSAC-II/ |access-date=2024-08-14 |website=computinghistory.org.uk | location=UK }}

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