COMPSCI 61C Lecture Notes - Lecture 2: Synchronous Dynamic Random-Access Memory, Rdram, Flash Memory
28 Aug 2017
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6 great ideas in computer architecture: abstraction (levels of representation / interpretation) Logic circuit description (circuit schematic diagrams: moore"s law. Every 2 years, the number of transistors / chip doubles (processing power doubles) Not true anymore because you can"t shrink in nitely. Jim gray"s storage latency analogy: how far away is the data: principle of locality / memory hierarchy. Ssd, flash drive (ssds are recommended in general by professors!) Single cores will switch between programs when waiting for data to be received. Programs may depend on each other: performance measurement and improvement. Failure rate of disks: 2 - 10% / year (~4% annual failure rate) On average, a disk fails once every hour. Real life example: nasa fixing rover"s flash memory. New software update to avoid using worn out memory banks: dependability via redundancy. Ensures that a failing piece doesn"t make the whole system fail. Numbers are usually stored with a xed size.
