computer science

UNIVAC 418

UNIVAC 418 is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand UNIVAC 418 rather than just read about it. In short: The UNIVAC 418 was a transistorized computer made by Sperry Univac. It had 18-bit words and used magnetic-core memory.

Key takeaways

UNIVAC 418 belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect UNIVAC 418 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of UNIVAC 418 from memory before moving on to harder problems.

Reference excerpt

The UNIVAC 418 was a transistorized computer made by Sperry Univac. It had 18-bit words and used magnetic-core memory. The name came from its 4-microsecond memory cycle time and 18-bit word. The assembly language for this class of computers was TRIM III and ART418. Over the three different models, more than 392 systems were manufactured. It evolved from the Control Unit Tester (CUT), a device used in the factory to test peripherals for larger systems.

Architecture The instruction word had three formats:

Format I - common Load, Store, and Arithmetic operations f - Function code (6 bits) u - Operand address (12 bits) Format II - Constant arithmetic and Boolean functions f - Function code (6 bits) z - Operand address or value (12 bits) Format III - Input/Output f - Function code (6 bits) m - Minor function code (6 bits) k - Designator (6 bits) used for channel number, shift count, etc. Numbers were represented in ones' complement, single and double precision. The TRIM assembly source code used octal numbers, as was common practice at the time for machines with word lengths evenly divisible by 3, but not by 4. The machine had the following addressable registers:

A - Register (Double precision Accumulator, 36 bits) composed of: AU - Register (Upper Accumulator, 18 bits) AL - Register (Lower Accumulator, 18 bits) ICR - Register (Index Control Register, 3 bits), also designated the "B-register" SR - Register ("Special Register", 4 bits), a paging register allowing direct access to memory banks other than the executing (P register) bank P - Register (Program address, 15 bits) All register values were displayed in real time on the front panel of the computer in binary, with the ability of the user to enter new values via push button (a function that was safe to perform only when the computer was not in run mode).

UNIVAC 418-I The first UNIVAC 418-I was delivered in June 1963. It was available with 4,096 to 16,384 words of memory.

UNIVAC 1218 Military Computer

The 418-I was also available in a version for the military known as the UNIVAC 1218. It was almost 6 feet tall and weighed 775 pounds (352 kg). It required both 115VAC, one-phase, 60 Hz and 115VAC, three-phase, 400 Hz power.

UNIVAC 418-II The first UNIVAC 418-II was delivered in November 1964. It was available with 4,096 to 65,536 (18-bit) words of memory. Memory cycle time was reduced to 2 microseconds. The version for the military was called the UNIVAC 1219 (known as the "Mk 152 Fire Control Computer.") It was part of the Navy's Mk 76 missile fire control system, used to control the AN/SPG-55 radar system.

UNIVAC 418-III The first UNIVAC 418-III was delivered in 1969. It was available with 32,768 to 131,072 words of memory. Memory cycle time was reduced to 750 nanoseconds. New instructions were added for floating-point arithmetic, binary-to-decimal and decimal-to-binary conversions, and block transfers up to 64 words. The SR register was expanded to six bits. The 418-III had two unique hardware features which enabled it to handle continuously high-speed serial character streams. One was called the buffer overflow interrupt and the other hardware buffer chaining. By the 1990s, all of the 418 hardware was gone, but the California Department of Water Resources was still running 418 emulation on a UNIVAC 1100/60. Customers included the London Hospital in Whitechapel, London, which installed its UNIVAC 418-III in 1973.

References

External links "The UNIVAC 418 Computer - Unisys History Newsletter Volume 4, Number 2 August 2000 by George Gray". Archived from the original on 28 March 2016. Retrieved 2 February 2018. UNIVAC 418 documents on bitsavers.org UNIVAC 1218 Military Computer 1964 BRL report from Aberdeen Proving Grounds The Automated Weather Network The USAF creates a real-time network of UNIVAC 418s 18-bit Computers - Computer Unit Tester, 1218 (CP-789), AN/UYK-5 Moonbeam, 1219B-CP-848/UYK, CP-914, ILAAS, 1819, AN/UYK-11(V) Article about the Univac 1219 and its use in the Navy's Tartar Missile System Design of the real-time executive for the Univac 418 system The Univac 1218 at the System Source Computer Museum

Worked examples

Example 1 — a first encounter with UNIVAC 418

Start with the simplest possible case. Write down what UNIVAC 418 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to UNIVAC 418 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about UNIVAC 418 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of UNIVAC 418

In research: UNIVAC 418 appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses UNIVAC 418 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: UNIVAC 418 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 18-bit computers, Military electronics of the United States, Transistorized computers, so understanding it makes those chapters shorter.
In everyday life: Look for UNIVAC 418 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study UNIVAC 418 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what UNIVAC 418 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain UNIVAC 418 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is UNIVAC 418 in simple terms?

The UNIVAC 418 was a transistorized computer made by Sperry Univac. It had 18-bit words and used magnetic-core memory.

Why does UNIVAC 418 matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study UNIVAC 418?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on UNIVAC 418.