Re: "kern", "kernel", "nucleus", "core"

Stefan Ram writes:
> The English words "kern", "kernel", "nucleus" and "core" could
> all be translated to the German word "Kern".

Correct for the last three, but not "kern"; that's something else
altogether. Its most common use today is in typography, where it
is etymologically related to "corner". Letters like A and V that
extend beyond their nominal width have kerns, and if you move them
closer together in the way that their shape allows, you are kerning
them or doing kerning.

Dictionaries show other meanings of "kern", but I have never heard
them used. From here on I am talking about the other three words.

> Where is the difference between them?

They do all mean pretty much the same thing, it's just that
different words have become customary in different situations.

> I assume an apple has a core...

Yes.

> and the operating system UNIX has a kernel...

Yes.

> (though programs might "dump" a "core").

No. This word refers to an obsolete type of computer memory, which
was the normal type from 1955 to 1980 or something like that. Each
bit was represented by a piece of ferrite in the shape of a torus,
which could be magnetized one way or the other; wires were strung
through them to allow them to be read or written using pulses of
electricity. Each of these toroidal pieces was called a "magnetic
core", and the whole thing was called a "magnetic core memory".

This was quickly shortened to "core", which was used as a mass noun.
You would speak of so many kilobytes (or megabytes) "of core".
As it was the only kind of main memory in common use, people used
the word "core" to mean memory. A dump of memory would be called
a "core dump", and the fact that UNIX and Linux systems still use
"core" in the name of the dump file is an anachronism.

> But for other cases, when does one choose which of these words?

One uses the one that is usual in a particular situation. I think
"core" is perhaps the most common and is more likely to be used
in cases where the thing has substructure, whereas a "kernel" is
more likely to be something small and indivisible (although that
really doesn't apply to an operating system kernel).

"Nucleus" is the least common. A cell (in biology) or an atom
has a nucleus; a group of important people within a larger group
may be called its nucleus, but also its core. I can't think of
any other common metaphorical uses.
--
Mark Brader, Toronto | "True excitement lies in doing
msb@xxxxxxx | 'sdb /unix /dev/kmem'" -- Pontus Hedman

My text in this article is in the public domain.
.

Relevant Pages

  • Re: off topic: LCD Terminal
    ... Once core became common, most memory ... Unsolicited bulk E-mail subject to legal action. ...
    (comp.os.linux.misc)
  • Re: Chucks plan
    ... Still, the external memory bus on the Intellasys I am interested what in particularly stopped it from having an automated memory bus, rather than the software driven bus? ... I asked the above separately, because potentially being on one core, it is not such a bottle next to every other core, and can drag in data faster, however, I am interested in how this played into the design? ... I would have expected that a word could have been dumped to the serial bus (link wakes up other core with first bit, core software reads port to tos, other bits automatically follow/streamed across and dumped into tos) and it streamed across to the receiving core at 700mhz*18, well within the boundaries of present intra chip busses. ...
    (comp.lang.forth)
  • Re: Chucks plan
    ... from having an automated memory bus, rather than the software driven bus? ... design was different, had to be designed separately, had ... This required predicting which memory chips will be most ... done with a Forth core and software this way. ...
    (comp.lang.forth)
  • Re: memory could not be "read"
    ... then the game will shut down after I press ok. ... Memory: 2048MB RAM ... Prime95, only runs two copies on a dual core processor for better testing. ...
    (microsoft.public.windowsxp.hardware)
  • Re: [opensuse] Re: RAM
    ... The more cores contending for memory access, ... go with the high-speed dual core rather than the low-speed ... Some instruction mixes have a much higher ratio of CPU internal instruction cycles to memory accesses than others. ... [I have a long story about how the execution time of an analyst's ...
    (SuSE)