Of all the rich person foundations, this is the one that feels the most hardcore.
They put huge focus on autism. Do they have an autistic child? Yes: www.forbes.com/pictures/eilm45mll/james-simons-autism/?sh=7825234250ce his daughter.
Refrigerator - How Does It Work? by Curiosity Show
. Source. In order to create a test user with password instead of peer authentication, let's create test user:
createuser -P user0
createdb user0-P makes it prompt for the users password.Alternatively, to create the password non-interactively stackoverflow.com/questions/42419559/postgres-createuser-with-password-from-terminal:Can't find a way using the
psql -c "create role NewRole with login password 'secret'"createuser helper.We can then login with that password with:which asks for the password we've just set, because the
psql -U user0 -h localhost-h option turns off peer authentication, and turns off password authentication.The password can be given non-interactively as shown at stackoverflow.com/questions/6405127/how-do-i-specify-a-password-to-psql-non-interactively with the
PGPASSWORD environment variable:PGPASSWORD=a psql -U user0 -h localhostNow let's create a test database which
user0 can access with an existing superuser account:createdb user0db0
psql -c 'GRANT ALL PRIVILEGES ON DATABASE user0db0 TO user0'We can check this permission with:which now contains:The permission letters are explained at:
psql -c '\l' List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges
-----------+----------+----------+-------------+-------------+-----------------------
user0db0 | ciro | UTF8 | en_GB.UTF-8 | en_GB.UTF-8 | =Tc/ciro +
| | | | | ciro=CTc/ciro +
| | | | | user0=CTc/cirouser0 can now do the usual table operations on that table:PGPASSWORD=a psql -U user0 -h localhost user0db0 -c 'CREATE TABLE table0 (int0 INT, char0 CHAR(16));'
PGPASSWORD=a psql -U user0 -h localhost user0db0 -c "INSERT INTO table0 (int0, char0) VALUES (2, 'two'), (3, 'three'), (5, 'five'), (7, 'seven');"
PGPASSWORD=a psql -U user0 -h localhost user0db0 -c 'SELECT * FROM table0;'In this section we will use the file nodejs/bench_mem.js, tests are run on Node.js v16.14.2 from NVM, Ubuntu 21.10, on Lenovo ThinkPad P51 (2017) which has 32 GB RAM.
Related answer: stackoverflow.com/questions/12023359/what-do-the-return-values-of-node-js-process-memoryusage-stand-for/72043884#72043884
First using
topp from stackoverflow.com/questions/1221555/retrieve-cpu-usage-and-memory-usage-of-a-single-process-on-linux/40576129#40576129 let's observe the memory usage of some baseline cases.For a Node.js infinite loop nodejs/infinite_loop.jsThis gives approximately:
topp infinite_loop.js- RSS: 20 MB
- VSZ: 230 MB
Adding a single hello world to it as in nodejs/infinite_hello.js and running:leads to:We understand that Node.js preallocates VSZ wildly. No big deal, but it does mean that VSZ is a useless measure for Node.js.
topp infinite_hello.js- RSS: 26 MB
- VSZ: 580 MB
Forcing garbage collection as in nodejs/infinite_hello.js brings it down to 20 MB however:
topp node --expose-gc infinite_hello_gc.jsFinally let's see a baseline for which gives initially:but after a few seconds randomly jumps to:so we understand that
process.memoryUsage nodejs/infinite_memoryusage.js:node --expose-gc infinite_memoryusage.js{
rss: 23851008,
heapTotal: 6987776,
heapUsed: 3674696,
external: 285296,
arrayBuffers: 10422
}{
rss: 26005504,
heapTotal: 9084928,
heapUsed: 3761240,
external: 285296,
arrayBuffers: 10422
}First a baseline case with an array of length 1:This gives the same results as with:
node --expose-gc bench_mem.js n 1node --expose-gc infinite_memoryusage.js. The same result is obtained by doing:a = undefinednode --expose-gc bench_mem.js deallocIf we use we see that the memory is now, unsurprisingly, accounted for under Results for different N:We see therefore that typed arrays are much closer to what they advertise (4 bytes per element), even for smaller element counts, as expected.
Int32Array typed array buffers instead of a simple Array:node --expose-gc bench_mem.js array-buffer n NarrayBuffers, e.g. for N 1 million:{
rss: 31776768,
heapTotal: 6463488,
heapUsed: 3674520,
external: 4285296,
arrayBuffers: 4010422
}|| N
|| `arrayBuffers`
|| `rss`
|| `rss` per elem
| 1 M
| 4 MB
| 31 MB
| 5
| 10 M
| 40 MB
| 67 MB
| 4.6
| 100 M
| 40 MB
| 427 MB
| 4Now let's try one million objects of type gives:Disaster! Memory usage is up to 70 MB! Why?? We were expecting only about 24, 4 baseline + 2 * 10 for each million int?!
{ a: 1, b: -1 }:node --expose-gc bench_mem.js obj{
rss: 138969088,
heapTotal: 105246720,
heapUsed: 70103896,
external: 285296,
arrayBuffers: 10422
}And now an equivalent version using gives the same result.
class:node --expose-gc bench_mem.js classLet's try Array:is even worse at 78 MB!! OMG why.
node --expose-gc bench_mem.js arr{
rss: 164597760,
heapTotal: 129363968,
heapUsed: 78117008,
external: 285296,
arrayBuffers: 10422
} Pinned article: Introduction to the OurBigBook Project
Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
Intro to OurBigBook
. Source. We have two killer features:
- topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculusArticles of different users are sorted by upvote within each article page. This feature is a bit like:
- a Wikipedia where each user can have their own version of each article
- a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
Figure 1. Screenshot of the "Derivative" topic page. View it live at: ourbigbook.com/go/topic/derivativeVideo 2. OurBigBook Web topics demo. Source. - local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
- to OurBigBook.com to get awesome multi-user features like topics and likes
- as HTML files to a static website, which you can host yourself for free on many external providers like GitHub Pages, and remain in full control
Figure 3. Visual Studio Code extension installation.
Figure 4. Visual Studio Code extension tree navigation.
Figure 5. Web editor. You can also edit articles on the Web editor without installing anything locally.Video 3. Edit locally and publish demo. Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.Video 4. OurBigBook Visual Studio Code extension editing and navigation demo. Source. 
- Infinitely deep tables of contents:
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact