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Cervisia

31 karma · joined November 14, 2015

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Cervisia··on Optimizing Top K in Postgres
The SQLite documentation explains how (and how well) this works: https://www.sqlite.org/optoverview.html#the_skip_scan_optimi...
Cervisia··on AI scrapers request commented scripts
> robots.txt. This is not the law

In Germany, it is the law. § 44b UrhG says (translated):

(1) Text and data mining is the automated analysis of one or more digital or digitized works to obtain information, in particular about patterns, trends, and correlations.

(2) Reproductions of lawfully accessible works for text and data mining are permitted. These reproductions must be deleted when they are no longer needed for text and data mining.

(3) Uses pursuant to paragraph 2, sentence 1, are only permitted if the rights holder has not reserved these rights. A reservation of rights for works accessible online is only effective if it is in machine-readable form.

Cervisia··on How Not to Buy a SSD
The sellers usually do not write "enterprise" in the offer. You have to know the model numbers (for example, the SK Hynix Platinum P41 is the same as the Solidigm P44 Pro and the SK Hynix PC801).
Cervisia··on How Not to Buy a SSD
There is nothing obviously suspicious with what's inside. The SATA form factor was designed for HDDs; solid-state drives usually are not much larger than a M.2 drive.

These flash part numbers look like Intel. This is actually plausible; until 2018, Intel and Micron had a flash partnership. And while their Crucial brand has some good high-end drives, they are also willing to sell absolute bottom-of-the-barrel trash.

What are these discrepancies, and what's off in the SMART values?

Cervisia··on Choosing an op-amp for your project
Nowadays, it is hard to recommend a general-purpose opamp. Just plug the desired parameters into the search function and sort what's left by price.

(Distributors like DigiKey and Mouser have somewhat adequate search functions; I usually have to go to manufacturers' web sites like https://www.ti.com/amplifier-circuit/op-amps/general-purpose... to be able to filter by all important parameters. I'm mentioning TI because they have a large selection and a good search; even when you do not end up selecting on of theirs, you see what is possible.)

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If you need only a small negative supply and have nothing else, the LM7705 charge pump can generate −0.23 V. (This is designed to fit into the typically allowed 5.5 V range of a nominal 5 V opamp.)

I do not know what a "significant current" is for you, but there are opamps with strong outputs. (When comparing opamps, you usually have to estimate the drive strength from the short-circuit current.)

Cervisia··on Types of Parser Combinators
The idea of parsing indeed is to transform data, from a lower level of abstraction to a higher level of abstraction.

Parsing text (a sequence of characters) or binary files (a sequence of bytes) are well known.

The author mentions the case where a JSON parser has generated a bunch of JSON objects, but you want your own object types. (Deserialization libraries can do this automatically if all that is required is setting fields or properties, but for more complex cases you need custom code.)

Similar for XML parsing: all you get is a stream of element events, or a tree of generic XML objects, and you have to transform that further.

Another case would be when you get import data in the form of an Excel or CSV file. Your code starts with a 2D array of generic cells/values, and has to transform it into your own table/object types.

Cervisia··on Writing an ALSA Driver (2007)
unix.stackexchange.com (or askubuntu.com); midi.org/forum; alsa-user mailing list; linux-audio-user mailing list

Please check if the device shows up in the output of "lsusb", "amidi -l", and "arecordmidi -l".

Cervisia··on Bug: Cat sitting on keyboard crashes lightdm
Related Linux kernel bug report: https://lkml.org/lkml/2011/11/3/110

However, that particular key combination ([Alt]+[SysRq]+[C]rash) works as designed. The old adage about security and physical access comes to mind.