Fred H wrote in message
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I'm currently working on deepening my understanding
on hard disk drives and file systems, and I have come
accross somethine that I find hard to get any relevant
hits on Google on: Record size.

Now, I know it has something to do with the
size of the chunck of data the OS/file system
is asking for from the disk when reading a
file, and the other way around for writing.

Records are an application level concept,
nothing to do with OS level file structures.

In other words applications impose
record structures on the OS level files.

You sure you arent talking about clusters rather than records ?

My question is best presented as a list I suppose:

- What is the definition of RS?

There is no nice tidy definition except that its
a chunk of data handled by the application. The
concept is clearest with database applications.

- How normal is it for a FS to vary it?

It has nothing to do with the OS level file system at all.
Its a construct that apply above the level of the OS FS.

- On what conditions does the FS vary RS, if it does?

It never does.

- Does "default RS" exist,

Nope.

and can I change it?

Yes, the application can obviously change it,
most obviously with database applications.

- Does the term "RS" mean fairly the same between FSs?

Not a meaningful question.

FS = File System and RS = Record size, but I suppose
that any of you that may actually be able to help me out,
understood that perfectly well ;-)

I know that the file system benchmarking tool IOZone
checks the file systems performance over two axis,
namely file size and record size,

It also uses the term 'transfer size'
which is an entirely different animal.

creating a 3D surface graph hoovering above the file size
/ record size "floor", with performance along the z-axis,
so I guess that sort of answers some of my questions.

Nope. Even the transfer size is an application level concept,
in this case the application being the benchmark.

But the reason I want to know more about record size,
is to better understand the results generated by IOZone.

Its basically the size of the chunk being moved at one time.

Slightly on another note, I'd like to ask you guys if
you know about any good web sites that deals with
file systems, and their inner structures and workings.

(The reason I'm trying to expand my horizon on the subject
is that I'm currently bench marking a computer with a circuit
"inserted" on the IDE-cable between the host and device.

Sounds painful.

This circuit has some fifos, and I'm trying to figure
out how important the sizes of these fifos are.

That obviously varys with the application
thats doing the reading and writing.

More specificially I'm hoping to find the breaking
point in the performance/fifo size graph, if it
exists in the fifo size range I'm operating in...)

There cant be any such animal independant
of the application generating the disk activity.

Thats the reason you see a variety of benchmarks with
hard drives, very different disk activity in different situations.