Mini-ITX, LinuxBios and DOC

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Does anyone know of any cheap, MiniITX mainboards that have two IDE ports
and either a working DOC socket/soldered on chip or a 32pin DIP removable
BIOS?

I want to make a standalone realtime CD copier so I need two IDE ports, one
for the reader and one for the writer. I wanted to run a simple Initrd from
a DOC which decompresses to main memory and performs the copying, without
using a Hard disk.

However, I have heard that the VIA mainboards dont work with a DOC even when
you solder one in place, so my other idea is to use the LinuxBios project to
have some boot code, Linux kernel and initrd in a DOC plugged into the bios
socket.

Looking at the LinuxBios website there seems to be some activity on the EPIA
VIA motherboards but it is unclear what the current status is.

It has been suggested that I use a biscuit PC but these tend to be 4 times
the price of a VIA miniITX mainboard so I am reluctant.

Any suggestions?

Thanks all, Vincent



Re: Mini-ITX, LinuxBios and DOC
Answering my own question for the group and google, I have been informed of
the following sites:-

MiniITX Mainboard with DOC socket, available from

http://www.lex.com.tw/ e.g. the BN860T, Approx 60 Euro without CPU. Very
neat.

LinuxBios Experts and Linux Bios on VIA EPIA amongst others

http://cwlinux.com - does not support initrd however.

Thanks to all who helped, Vincent




Re: Mini-ITX, LinuxBios and DOC

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Is this a problem?  You know exactly what your hardware configuration is
so I'd assume that you'll compile everything you need into your kernel.

Are there issues with, for example, having the root filesystem on a USB
device?  (IOW, the BIOS can handle loading the kernel from it, but the
kernel can't handle running from it?)

--kyler

Re: Mini-ITX, LinuxBios and DOC
I was going to have a moduleless kernel and have my application and
everything in the initrd.

The idea of linuxbios is that you replace the bios with a doc. YOu then
program a bootloader which initialises the motherboards regsiters, loads the
kernel and then can load an initrd from the doc. This allows quicker boot up
time, custom display if you have one etc, along with the non-requirement for
a root file system.

I will use a moduleless kernel but i wanted to have my application in the
initrd file too decompressing to ram, without using a flash, usb, DOM etc as
the root file system.



Re: Mini-ITX, LinuxBios and DOC

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Besides the quicker boot, it doesn't buy much for your application, does it?
Everything else you can do without touching the motherboard with much less
expensive and more readily available hardware.  (I've only read about the
custom BIOS images but haven't implemented them.  I'm confident it's fairly
easy to do.)

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Why the extra complexity?  A compressed root file system is only an advantage
if you're constrained by a tiny storage device.  It's going to be hard to
find a USB or CF memory device that small these days.  It will be much easier
to develop with a regular filesystem (which you can switch to writable when
you need) and won't require so much system memory (not that it's a big
expense).

It sounds like you have your heart set on making this difficult.  If it
results in more LinuxBIOS work, that great for me, but I'd still like to know
if there's any real advantage to it (besides the value in tinkering).

--kyler

Re: Mini-ITX, LinuxBios and DOC
What about to use a DOM (Disk On Module) instead of DOC ?




Re: Mini-ITX, LinuxBios and DOC
DOM has a IDE-like interface not only in SW but also in HW, so it's
easier to use it instead of DOC.

B.Rgds,

Lawrence Lew

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Re: Mini-ITX, LinuxBios and DOC
Both IDE ports are busy with CD rom drives. I dont want a compact flash to
die converter which performs the same function either, nor do i want a usb
boot device plugged into the internal usb ports.

The BN860T motherboard will fulfill my requirements.

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Re: Mini-ITX, LinuxBios and DOC

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Not when the machine is booting.  (I suppose that *is* a reason to use a
RAM disk for the root filesystem.)

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Any technical reason or is this just an emotional decision?

--kyler

Re: Mini-ITX, LinuxBios and DOC
The original post said that both IDE ports will be busy, with CD writers.

As you say, in the beginning, a flash disk could be used for boot. But I was
hoping to produce a system with as few connectors and fiddly bits as
possible, hence the DOC socket or LinuxBios DOC in a Bios socket. DOMs, CF
and the like make this more fiddly.

Im looking to make the footprint as small as possible and as shallow as
possible, which is further makes me fancy the DOC option.

Cheers, Vincent


----- Original Message -----
Newsgroups: comp.os.linux.embedded
Sent: Friday, September 19, 2003 4:10 PM
Subject: Re: Mini-ITX, LinuxBios and DOC

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usb



Re: Mini-ITX, LinuxBios and DOC

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...and my post pointed out that they're *not* busy at all when
booting.  You realize you can have two devices on an IDE line, right?

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Fiddly?  O.k....

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Hmmm...once you get so tight that you can't fit a tiny USB key in there,
I suspect you're going to have trouble dissipating heat.  Heck, just
bending the power cable to keep it that low would scare me.

--kyler

Re: Mini-ITX, LinuxBios and DOC
Firstly, Thanks to Kyler and Lewen and the others who have replied directly
with this post.

The reason I wanted to have a CD writer on each of the IDE sockets was
because I was wanting to write dual CDs simultaneously. I was under the
impression I could not do this when connecting both devices, one as a master
and one as a slave, to each IDE port or channel.

Since I have a CD writer connected to each IDE channel, I assumed I would
not be able to use an IDE persistant storage device. This now looks like I
was wrong since the IDE channel may be used for booting, decompressing to
ram then running from ram, and can then be forgotton about.

The IDE CF converters I have toyed with are quite large and I was trying to
go for the small sizes, hence I was attracted to the DOC option. I was
already concerned with connectors for the slimline CD to conventional IDE
cabling, and in my experience cables and connectors and adaptors can be a
problem. The LinuxBios DOC option was doubly attractive since it allowed me
to have a quicker boot time.

The Biscuit PCs I have seen tend not to have dual IDE ports but I would be
happy to be proved wrong. I also need sound support, which is not always
offered by biscuit PCs.

The Mini-ITX option just seemed to be a low cost route to developing a
prototype to show off with, since the mothebroard is around the same size as
the CD writer. I was looking at using one of the switchmode PSU plugged
directly into the ATX power commector and use a wall cube PSU to provide a
neat base unit.

Hope this clarifies my situation, Vincent







Re: Mini-ITX, LinuxBios and DOC

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I think you're right to avoid that.  Keep them on different interfaces.

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Yes, that should work nicely for you.  I don't know if there's any advantage
to running the CD drives both as IDE "master" devices, but I think you
should be able to do it and still boot from a "slave" device.  (Strangely
enough, I've had the need to do that on one of my machines.)

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I have some large IDE-CF converters too (with RS-232 ports?!).  More
recently I've gotten much smaller ones from Mesa.
    http://www.mesanet.com/diskcardinfo.html
They're still a little larger than what I'd like.

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Ug.  Yes, I hate the CD connector thingies.  The one I have falls out with
the slightest nudge.

I would definitely try booting from USB.  You should be able to get a nice
compact easily-mounted system that will solidly connect to the USB header
on the board.  Because it won't tie up the IDE interface, you could even
safely use it without expanding to a RAM disk.  With a USB 2.0 device, the
speed should be quite sufficient.  And they're *cheap* and easy to find.
Have a problem?  Pull it out and stick another one in.  Try that with DOC.
It should make development much easier too since you can test one while
you load another on your desktop machine.

I've only read about booting from USB memory but I haven't tried it yet.
I'm thinking that I'll order some cheap tiny USB 1.1 devices
    http://www.compgeeks.com/details.asp?invtid=USBIS256-N
to get started.

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I have several like that.  They're great.  Sometimes I even run them off
of a 12V battery.  So if you ever want to turn your CD duplicator into a
"boom box"...  (You could also add a small battery just to keep it alive
if someone bumps the power cable.)

--kyler

Re: Mini-ITX, LinuxBios and DOC

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Ah!  I think a few of us have been talking past each other on this
subject.  I finally realized that you might be saying "ports" to
mean "master and slave devices on a single IDE interface".

Is it the case that you only have one IDE interface on the boards
that you've been checking?  There are certainly Mini-ITX boards
around with dual IDE adapters that would easily support two CD
drives (independently even) along with a boot device.  If you're
having trouble finding some, let me know.  I'm fairly sure that
some of the ones I have are dual IDE.

--kyler

Re: Mini-ITX, LinuxBios and DOC

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Right, I think we all agree it's much easier to deal with DOM.

Why use it instead of an IDE-CF adapter and a CF card?  Besides being
amazingly cheap and readily available, the CF card can be easily
reprogrammed by most any laptop.  This makes development especially
convenient in some situations.  ("Oops!  I just hosed the disk...")

--kyler

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