ILLIAC II
Early supercomputer built by the University of Illinoiw
The ILLIAC II was a revolutionary super-computer built by the University of Illinois that became operational in 1962.
Description
The concept, proposed in 1958, pioneered emitter-coupled logic (ECL) circuitry, pipelining, and transistor memory with a design goal of 100x speedup compared to ILLIAC I.
ILLIAC II had 8192 words of core memory, backed up by 65,536 words of storage on magnetic drums. The core memory access time was 1.8 to 2 μs. The magnetic drum access time was 8.5ms. A "fast buffer" was also provided for storage of short loops and intermediate results (similar in concept to what is now called cache). The "fast buffer" access time was 0.25 μs.
The word size was 52 bits.
Floating-point numbers used a format with seven bits of exponent (power of 4) and 45 bits of mantissa.
Instructions were either 26 bits or 13 bits long, allowing packing of up to four instructions per memory word.
Rather than naming the pipeline stages, "Fetch, Decode, and Execute" (as on Stretch), the pipelined stages were named, "Advanced Control, Delayed Control, and Interplay".
“ILLIAC II” enters the record as early supercomputer built by the University of Illinoiw. Crown Archives preserves that source wording while asking what ILLIAC, Early and supercomputer can confirm, complicate or overturn.
Why this record matters
“ILLIAC II” is worth following because a concise public description often conceals a longer documentary argument. Here, ILLIAC, Early and supercomputer provides the most credible route into that argument.
Contemporary correspondence, administrative files and participant testimony can test how later narratives organized the event or institution. The source revision retrieved here is dated Aug 19, 2026. The linked authority identifier is Q5971785. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1962 and 1958.
Later summaries often reconcile disputed chronology or motive more neatly than the contemporary record permits. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Compare institutional narratives with records created by participants and affected communities. Dates and formal titles are useful anchors, but not substitutes for context.
- Event chronology
- Institutional context
- Locating named record creators
Contemporary correspondence, government or organizational records, oral histories and cited historical scholarship.
Three-step research path
- Establish the record: confirm the title “ILLIAC II”, its source revision and the description used here.
- Expand the search: follow ILLIAC II primary sources, ILLIAC II archive and ILLIAC research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “ILLIAC II”?
- What chronology connects this entry to wider political or social change?
- Which voices are present, absent or mediated by the institution?
Search terms from this dossier
This entry incorporates text from “ILLIAC II” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.