computer science

JEIDA memory card

JEIDA memory card 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 JEIDA memory card rather than just read about it. In short: The JEIDA memory card standard is a popular memory card standard at the beginning of memory cards appearing on portable computers. JEIDA cards could be used to expand system memory or as a solid-state storage drive.

Key takeaways

JEIDA memory card 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 JEIDA memory card to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of JEIDA memory card from memory before moving on to harder problems.

Reference excerpt

The JEIDA memory card standard is a popular memory card standard at the beginning of memory cards appearing on portable computers. JEIDA cards could be used to expand system memory or as a solid-state storage drive.

History Before the advent of the JEIDA standard, laptops had proprietary cards that were not interoperable with other manufacturers laptops, other laptop lines, or even other models in the same line. The establishment of the JEIDA interface and cards across Japanese portables provoked a response from the US government, through SEMATECH, and thus PCMCIA was born. PCMCIA and JEIDA worked to solve this rift between the two competing standards, and merged into JEIDA 4.0 or PCMCIA 1.0 in 1990.

Usage The JEIDA memory card was used in earlier ThinkPad models, where IBM branded them as IC DRAM Cards. The interface has also been used in SRAM cards.

Versions Version 1.0 is an 88-pin memory card. It has 2 rows of pin holes which are shifted against each other by half the pin spacing. The card is 3.3mm thick. Released in 1986. Version 2.0 is only mechanically compatible with the Version 1.0 card. Version 1.0 cards fail in devices designed for Version 2.0. Released in 1987. Version 3 is a 68-pin memory card. It is also used in the Neo Geo. Released in 1989 and has variants with 20, 34, 40 and 68 pins. Version 4.0 corresponds with 68-pin PCMCIA 1.0 (1990). Version 4.1 unified the PCMCIA and JEIDA standards as PCMCIA 2.0. v4.1 is the 16-bit PC Card standard that defines Type I, II, III, and IV card sizes. Version 4.2 is the PCMCIA 2.1 standard, and introduced CardBus' 32-bit interface in an almost physically identical casing.

See also Japan Electronic Industries Development Association Japan Electronics and Information Technology Industries Association Personal Computer Memory Card International Association Compact Flash

References

External links IC DRAM Card - Thinkwiki.org

Illustrations

Worked examples

Example 1 — a first encounter with JEIDA memory card

Start with the simplest possible case. Write down what JEIDA memory card 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 JEIDA memory card 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 JEIDA memory card 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 JEIDA memory card

In research: JEIDA memory card 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 JEIDA memory card 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: JEIDA memory card is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computer buses, Computer hardware stubs, Motherboard, so understanding it makes those chapters shorter.
In everyday life: Look for JEIDA memory card 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 JEIDA memory card in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what JEIDA memory card 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 JEIDA memory card out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is JEIDA memory card in simple terms?

Why does JEIDA memory card 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 JEIDA memory card?

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 JEIDA memory card.