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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