Fundamental Digital Electronics (Spring 2014 )

transcript

Fundamental Digital Electronics (Spring 2014)

Martino Poggio

2Fundamental Digital Electronics

Hard disk drive (HDD)

• Introduced by IBM in 1956• Dominant form of secondary storage• Pros: capacity, price, performance• Cons: size, durability

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HDDs in the last 30 years

• Capacity: 3.75 MB 4 TB• Volume: refrigerator 20 mL• Weight: 910 kg 48 g• Density: 2 kbit/in2 600 Gbit/in2

• Price: 15k USD/MB 0.0001 USD/MB• Access time: 100 ms 3 ms

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Millipede Memory

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Millipede Memory: Concept

• Store bits as high density “divots” in a polymer film

• Use many nanoscopic cantilever tips in parallel to read and write

• Achieve stability of HDD and speed of DRAM…

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Millipede Memory: Read

• Read: probe tip heated to 300 C, and moved over data point; measure temperature of the canitlever; if there is a divot, heat will leak from the tip quickly; if not. heat will leak slowly.

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Millipede Memory: Write

• Write “1”: probe tip heated to 400 C (above glass transition) and pushed into the surface; tip pulled away after cooling.

• Write “0”: prove tip heated to 400 C and pushed into the surface; tip pulled away still hot, allowing surface tension to pull the surface flat.

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Millipede Memory

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Millipede Memory

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Millipede as of 2005

• Density: 800 Gbit/in2

• 64 x 64 cantilevers• Pit size: 10-20 nm

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Flash Memory (SSD)

• Introduced by Toshiba ca. 1980• Growing form of secondary storage• Pros: size, durability (no moving parts!), power

consumption, speed• Cons: capacity, long-term reliability, price

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Flash Memory (SSD)

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Flash Memory (SSD)

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Flash Memory (SSD)

• Memory wear: 1k – 1M cycles… and improving• Read disturb• Capacity: 256 GB in 2012…• Faster at reading than writing

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Flash Memory (SSD)

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Fundamental Digital Electronics (Spring 2014 )

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