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fuzztester

Some more:

hex

octal

binary

how to convert between the above 3, and between them and decimal

bit twiddling

the difference between ASCII and binary files (even pre-unicode)

the fact that a source code program compiled on one processor architecture will not run on another without recompilation on the target, apart from cross-compilation - at least in most cases this was true, though there might be differences nowadays, for apple products, java and other bytecode, etc.

endianness

...

I have actually talk to various people who did not know all of the above topics, although not necessarily all in the same person

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> the difference between ASCII and binary files

This one is a bit confusing. In DOS/Windows land, files are just files, always binary. The distinction between "ASCII" and "Binary" only exists at the time you call "fopen" (a C function), then failing to open in binary mode causes it to mangle your data by inserting CR before every LF.

Not all operating systems have file systems that take the Unixoid "a file is just a hunk of bytes on disk with a name" (which convention DOS, Windows, and Mac also use). Some file systems do distinguish between text and binary files; others have fixed record sizes, or provide fixed-record-size files in addition to random-access hunks of bytes. Mainframe and DEC mini operating systems come to mind.

Sorry, loose wording or brain fart there.

I meant text files vs. binary files, as in, you can open text files in a text editor and see their contents, but if you open a binary file in a text editor, you get what appears to be garbage, but that is not an error, because of all the non-printable characters they often contain.

But at one level you are right, of course, files are just files. It is the higher layers of software and humans that give different interpretations to them, such as text vs binary.

People with computer related degrees?

I still remember my google buddy talking about being aghast his intern (who was a CS major who obviously passed with flying colors and went to stanford or yale, I dont remember) not knowing what an IP address was.

I've conducted interviews of professed Unix devs or sysadmins, some years ago, who didn't know what the setuid bit was, or confused it with the sticky bit.

https://en.m.wikipedia.org/wiki/Setuid

https://en.m.wikipedia.org/wiki/Sticky_bit

Heh. These days, a computer science degree is essentially equivalent to a coding degree. But depending on the decade and curriculum, it was traditionally a branch of mathematics and one could theoretically go all the way to PhD while never actually touching a practical computer.

There used to be a saying: Computer science is no more about computers than astronomy is about telescopes.

And that is why in this article, ESR has titled it, Things Every _Hacker_ Once Knew. Hackers usually have some sort of passion for the technology itself and want to understand ALL of the practical details and history of a thing. Hackers are _very much_ about computers.

Some. One was Comp. Engg. Not sure if any CS.

If a young'un should ask my age, I report it in hex. Keeps 'em on their toes.

he he. try octal on em, will be harder.

One of the filesystem related crates I was futzing around had an example where they set the file permissions to 0444. In Rust. Whooops.

I have actually talk to various people

>talked, voice-to-text error

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