Re: [Gnu-arch-users] Some issues

[James Blackwell]

>> Huh?  What about seek overhead?
>

Andrew Suffield
> What seek overhead? There is no strong relationship between "being in
> the same file" and "being in the same region of the disk", and no
> strong repulsion between "being in different files" and "being in the
> same region of the disk". These things are mostly related to creation
> pattern, not file membership.

512 bytes per sector = 7 arch-ids per sector. 

What's more, most interesting filesystems know how to defragment files,
so your seek time goes down.
.

> Interesting filesystems do not seek the head to park and back every
> time they read from a different file. They actually do the opposite,
> and reorder disk accesses to minimise seeks.

Who said they did? 

Reordering disk accesses won't make a whit of different to arch until
some date in the future it makes all of those requests concurrantly.

> HFS+ goes further, and shuffles small files around so that the ones
> you use most often are stored near each other; this doesn't work if
> you cram them all into one huge file. (NTFS is just inefficient at
> allocating large files, and tends to scatter them, while small files
> are packed together more densely; yes, its allocation algorithm
> sucks).

A file with 10,000 arch-ids is about 730K. I don't know in who's world
this is considered a "large file". 

-- 
James Blackwell          Try something fun: For the next 24 hours, give
Smile more!              each person you meet a compliment!

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