Re: SSD TBW

On 8/22/26 20:57, Don Y wrote:
> On 8/22/2026 8:51 PM, Rich wrote:
>> In comp.misc Don Y <[email protected]> wrote:
>>> Sadly, UNIX assumes file type is completely indicated by
>>> a suffix on a filename -- said suffix being under the control
>>> of the person who selected the filename.
>>
>> Nope.  You are mixing up ms windows (where the file extension is
>> believed to always be right and descriptive of the contents) with Unix
>> (which actually looks at the files contents and pays no attention to
>> any part of the name).
> 
> One configures applications (CVS in this case) to use the extension
> of the file as an indication of how it should be treated.
> 
> The contents still don't tell you what the file is or how it is intended
> to be used.  Because no OS can infer the purpose of a "stream of bytes"
> without having been previously informed of that.
> 
> When a file (or, the metadata for the file) claims it is a
> "FIGGLEBOB", then the OS can throw up its hands and claim
> not to know how to handle it -- even if it looks like a shell
> script, text file, TIFF, etc.  Because the explicit type declaration
> has told it that it is none of those things, despite the resemblance.
> 
> Is a .AI file a "text" file -- because the contents APPEAR to be
> text -- even though they aren't really?  Is myprogram.q source
> code in C, just because peeking inside LOOKS like that's the case?


Search "magic numbers"

I looked at a few hits, this page is better than most, the first 
paragraph should be enough.

<https://www.networkworld.com/article/931352/unix-under-the-spell-of-magic-numbers.html>