Re: Mass storage devices

From: P.T. Breuer (ptb_at_oboe.it.uc3m.es)
Date: 01/19/04 

Date: Mon, 19 Jan 2004 18:50:16 GMT

Wolf Kirchmeir <wwolfkir@sympatico.can> wrote:
> [yadda yadda attribs lost]
> =>> stores or manipulates data is none of the OS's business; a
> =>> mass storage device can store the data any way it wants, so
> =>> long as it preserves the data format. Correct me if I'm
> =>> wrong, but data formats aren't the same thing as file
> =>> systems, and are definitely not the same as physical
> =>> encoding systems.
> =>
> =>True, but partitioning systems are none of the above.
>
> True, and I confess I haven't thought much about this
> aspect. "Partitions" or "volumes" are needed in a networked
> environment to control access to files, correct? H'm. IMO,

No, no. They control the major modes of working. For example, one
partition may be journalled, another may be atime, another may
be synchronous, another may be readonly. And of course they may be
different kinds of filesystem - one may be xfs, another resiserfs,
another ext2, another ntfs.

I suggested "nfs". I think your idea of a disk presenting itself
through a hierarchy of directories is a good one. Yes, one can do this,
and it is being developed - the idea is to put a cpu in the disk so
it presents itself like an nfs server, and is plugged in via an
ethernet cable, not an ide cable (see "power over ethernet" on the
net).

> that's an OS permission issue, and really doesn't have much
> to do with how the MSD (mass storage device) stores data.
> That is, whether a file belongs to some "volume" or "owner"
> or not, is information that can be added to the file
> itself. AFAIK, this is already the case, so there isn't
> really an issue w/ regard to smart drives. Or am I missing
> something?

Fine, but one needs to control the devices major modes, perhaps on an
area by area basis. But I like your concepts.

> convinced that the OS needs to know about them. Surely it's
> the RAID array's business? I guess what I'm arguing is that
> the OS and MSD only need to know how to communicate with
> each other.

They do - see nfs. Linux in particular has a VFS (Virtual File System)
layer, so any file system merely has to implement its hooks and linux
can talk to it. We *already* don't know anything about the internals of
any file system we talk to :-). The extra step you are advocating is
putting the code that deals with that file system outside of the kernel
altogether, even on a different processor (as I suggest) on the disk
itself. But the location of the processing is the only extra over what
we already have. I suggested "nfs".

> At present some form of MSD operating system is
> built into the OS, and that is merely a legacy IMO. There's
> no need for it. (IMO there never was a need for it, but
> maybe there were good arguments for it in the early days of
> personal computing.) But if there are security issues that
> I've overlooked, I'm willing to be convinced.

It's not true. You can run your PC without any sort of disk at all,
connected entirely over the net, with nfs root. That has always been
the case.

> Please keep in mind that I'm writing as a user, not a
> developer or admin, and that from my POV, the fact that I
> can't just buy any old HD or other MSD and just plug it in
> and use it is a major PITA.

Eh? But you can plug it in and use it. What is a MSD? I thought you
meant "MS DOS". Oh, Mass Storage Device. Yes - you can plug it in,
if it adheres to the standards.

But wait for disk over ethernet.

> Come to think of it, the fact that I need a "driver" for
> any peripheral is a major PITA - surely it's possible to
> get past that?

Sure. Put the peripheral on another machine and contact it via the net.
Even better, leave the peripheral with the manufacturer and hire rights
to connect to it ...

(and don't get me going about swap over ethernet ...)

Peter

Relevant Pages

  • Re: What kind of conspiracy is like this?
    ... the volume so low that I could almost hear the sound and that was totally ... Apart from the control over human body and electricity appliance, ... and relative to the floppy disk. ... whole set of PC on my hard disk, co-processor, PNP mouse, keyboard, etc. ...
    (microsoft.public.windowsxp.general)
  • what kind of conspiracy is this?
    ... important I could not hear any sound from that family I fight with when the ... Guy lives upstairs hit his ground to this. ... Apart from the control over human body and electricity appliance, ... and relative to the floppy disk. ...
    (microsoft.public.windowsxp.help_and_support)
  • What kind of conspiracy is like this?
    ... important I could not hear any sound from that family I fight with when the ... Guy lives upstairs hit his ground to this. ... Apart from the control over human body and electricity appliance, ... and relative to the floppy disk. ...
    (microsoft.public.windowsxp.general)
  • what kind of conspiracy is this?
    ... important I could not hear any sound from that family I fight with when the ... Guy lives upstairs hit his ground to this. ... Apart from the control over human body and electricity appliance, ... and relative to the floppy disk. ...
    (microsoft.public.windowsxp.work_remotely)
  • What kind of conspiracy is this?
    ... important I could not hear any sound from that family I fight with when the ... Guy lives upstairs hit his ground to this. ... Apart from the control over human body and electricity appliance, ... and relative to the floppy disk. ...
    (microsoft.public.security)