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Play Framework

Important files

Directory structure

• conf/routes defines how application routes HTTP GET requests to an action. Example:

# URI '/' calls index view (index.scala.html) 

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Getting Started

• Run openocd -interface_list. The ftdi interface driver should be listed.

Configuration file

Link to example configuration file --> https://github.com/cho45/raspberrypi-mruby-bare-metal/blob/master/openocd/generic-ft4232h-libftdi.cfg

• Run `openocd -f <file.cfg>

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Frontend Frameworks

NPM

npm is the package manager for JavaScript. Install using apt install npm.

• Setup repository: cd public/js && npm init -y

• Install modules and dependencies

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Docker

This install guide is used as the primary reference. Make sure to remove all old docker installs before continuing.

Also see: https://gist.github.com/edcote/0dfd1f9f26c628ba1a3dbb2860ebd7dd

Important commands

• List all containers docker ps -a
• Remove container docker rm #container

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Notes

"What doesn't get measured might not get done". Coverage helps to answer the "are we done" question.

Two concepts fundamental to understand coverage.

• Controllability: ability to influence FSMs, structure, or LOC in the design
• Observability: ability to obseve the effects of a FSMs, structure, or LOC in the design

Kinds of coverage:

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Source

• DDR3 SDRAM has eight banks, which allows more efficient interleave

Output driver impedance (Ron), ODT and ZQ calibration

• The output driver impedence (Ron) of DQ, DQS, /DQS, and DM is selectable. Ron may fluctuate with PVR. DDR3 uses ZQ calibration.
• ODT (On Die Termination). A termination resistor is provided by the chip to suppress signal refection. ODT resistance Rtt can be adjusted by MR2.
• ZQ calibrate long to be issued during initialization. ZQ calibrate short to issue periodically during operation.

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Summary

• Networks must be hierarchically composable. Topology must form DAG.
• MOESI-equivalent protocol

Channels

• Channel A : M-S : Request
• Channel D : S-M : Data response
• Channel B : M-S : Snoop (Request that an operation to be performance at an address cached by a master, accessing, or writing back that cached data)

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Scala Notes

Variables

Immutable and mutable

Scala has two kinds of variables, vals and vars:

• val is immutable, cannot be reassigned
• var is mutable, can be reassigned

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Why CMake? Why? It is only me or do I find CMake to be convoluted and non intuitive?

• Debug vs. Release:

Technically, this is all that is needed:

cmake -DCMAKE_BUILD_TYPE=Release ..
cmake -DCMAKE_BUILD_TYPE=Debug ..

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MongoDB

MongoDB stores data in flexible, JSON-like documents. The document model maps to object in your application code, making data easy to work with. MongoDB is a distributed database at its core.

Here. Be careful, need 3.4 or later.are notes on how to install MongoDB on RHEL7.

Spark and MongoDB

MongoDB is a document store (and essentially a database). Spark is a computing engine and not a store. When used together, Spark jobs can be executed directly on operational data sitting in MongoDB.