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Darren New schrieb:
>> Then again, I've sometimes wondered what would happen if you had some
>> filesystem that split the disk into several seperate regions with
>> different block sizes, and allocated files accordingly. (I.e., put the
>> really huge files in the area with big blocks, and the tiny files in
>> some area with tiny block sizes.) I rather suspect you'd permanently
>> be running out of whichever size you happen to need the most tho...
>
> And interesting thought. I've never seen that done. Given that disks
> are broken into sectors all the same size, and given that the only
> reasons for allocating space in units larger than one sector are
> defragmentation and efficiency of storing pointers to clusters, there's
> no real good reason for it.
You are aware that modern file systems use block sizes /significantly/
larger than the disk sector size?
A disk sector is 512 byte in size virtually everywhere, while file
systems typically use block sizes one order of magnitude larger.
Why? Because it is actually more memory-efficient to /not/ use even the
smallest gaps - because that inflates the required management overhead,
severely reducing the total payload capacity when the files are
sufficiently /large/ on average.
In the end, some compromise is used, based on the statistical
distribution of file sizes. A really /good/ system administrator might
tune the various volumes on his systems to have block sizes that match
the actual use.
> On the other hand, the Amiga formatted the floppy track every time it
> wrote the track, so you could probably actually fit more large files on
> a disk than small files, even if every small file was exactly one
> sector, by making the sectors physically larger on tracks where they
> store a big file.
That won't work for hard disk drives: Even if you /could/ still
low-level-format them (and maybe that's actually still possible with
special tools), it would be a particularly bad idea, given that they
don't even disclose their actual drive geometry anymore these days
(aside from the /official/ total capacity - but even that may be only
half the truth, as I heard say that modern hard drives reserve some
sectors as spare, to deal with sectors that over time begin to "almost
lose data", i.e. become seriously difficult to read - so those can be
avoided and operation can safely continue without any true problems
while the system administrator orders a new drive - provided he has kept
an eye on the SMART status of his drives).
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