Re: [SLUG] Projector & home theater pc

From: steve szmidt (steve@szmidt.org)
Date: Mon Mar 12 2007 - 22:36:00 EST


On Saturday 20 January 2007 15:54, michael hast wrote:
> Well, guys, I think I'm going to haul off and do it. I'm getting tired
> of watching TV and movies on an itty bitty TV. I've pretty well decided
> that a projector is going to do well for my purposes, and that I'd like
> to run it with a PC. Do any of you know what tuner cards work well with
> Linux? Also, if any of you have advice on projectors, I'd love to hear
> it. For that matter, Steve, do you think Sabayon might be a viable OS
> for the machine? I'm open to advice there too. (In fact, I think I've
> discussed that here before...) Thanks!

I built a middle of the road solution, a network storage device (NAS). The
intentions are still to build a full media PC but for now I had a solution
fall in my lap.

A friend of mine gave me an IOMEGA NAS drive, which is a networked PC with
storage that you can use from any other computer. It's a pretty expensive 1U
rackmount solution, $2,600.

Built around an OEM only motherboard by ABIT, the TS-20 is an interesting
Micro ATX form factor PC. It comes with dual LAN ports but no sound or
parallel port. Which of course is not really the purpose with a NAS drive.

What looked very interesting is the fact that this small m/b comes with four
IDE controllers able to run eight drives, and one expansion slot. Running at
1GHz and 512MB it's not a speed daemon but again plenty for a NAS.

It comes with the Highpoint HPT 370 chipset which offers RAID, inluding RAID
0+1, or RAID 10 as some people like to call it. (Basically that is using both
RAID 0 and RAID 1, which means two drives in series that gives doubled
capacity and another two which duplicates the first two giving speed and
redundancy.)

Unfortunately HPT 370 requires windows to work and are in essence a cheap way
of getting RAID by moving some hardware functionality to the O/S. (Like a
windows modem or printer.)

IOMEGA uses a very nice case with four hotswappable drives with independent
drive & network lights. It's easy to see what is going on externally.

What got me excited about this is that I could build a system that has a low
load on each drive to store and play music and movies from.

It comes with FreeBSD, but on my copy it had stopped working properly. IOMEGA
only offers to sell a new drive, no repairing of the (boot) drive. Which is
how I got the box. My friend figured I could put Linux on it and make use of
it. (I had built him a Linux RAID system that pushed over 90MB/sec, so he was
already set.)

Installing any O/S on this became a challenge as it does not have space for a
CD/DVD player and very interestingly, only supported four drives. "Wait!",
you may call, "you said it supported eight drives! What gives?"

IOMEGA has crippled the system (to not compete with higher end solutions no
doubt) and are using a backplane to connect the drives to. The problem is
that by using the drive backplane you can only connect four drives. And as
you may recall for RAID 0+1 you need a minimum of four drives. No room for a
fifth CD/DVD to install from.

So what I did was to disconnect the drives from the backplane and connect them
directly to the controllers. Making the CD secondary on the primary
controller I could install from the CD and then remove it without changing
the drive IDs.

I picked RAID 1 for the boot partition and RAID 6 for swap, var and root. RAID
1 is the highest RAID you can use for booting, and RAID 6 adds an extra level
of redundancy. RAID 5 uses a stripe of parity reaching across all drives and
allows you to loose one drive and still work. With RAID 6 it puts on two
stripes of parity and you can loose two drives. So this setup of four drives
can survive a 50% loss without loosing data.

I added smb for remote network access and now all our music and video's reside
on the NAS. Listening on music puts an average of 20k load on the network and
about 5Mb when watching a movie. Interestingly (on my desktops) Sabayon has
nice support for smb but FC6 does not.

What I like about it is that running RAID 6 is very resistant to data loss,
and having the multimedia spread across four drives lowers the load on each
drive. By having the hole shebang on RAID I don't need to manually rebuild a
failed boot drive as many of these systems require.

The system came with four 80G drives, but I can now see replacing those with
higher capacity drives (probably need to do it soon as SATA is quickly
replacing IDE manufacturing.)

Four 80G drives on RAID 6 gives a bit over 140G. Which, unless you are
stockpiling DVDs, is plenty for a lot of multimedia. We have ripped all our
CDs and by placing movies online can view and listen to them at our own
leisure from any computer.

Now I don't have to worry about a desktop or server computer going down
because of drive failure from playing multimedia. I'm not likely to loose any
music either due to using (software) RAID 6. Running software RAID does not
put much load on the CPU either and the system runs pretty cool.

The $2,600 price tag is very excessive for a system like this. A normal
motherboard with two IDE controllers and four drives does the job just fine.
Though you may need to temporarily add something like a PC133 IDE card to be
be able to use a CD/DVD while building the system.

The PC133 IDE card is supposed to add 133MB transfer rate controller to a
motherboard which lacks it. Usually it comes with two controllers supporting
four drives. (Sometimes you loose one of the controllers on the motherboard
while using the card, but what is important is that it leaves you with
support for six drives, allowing the otherwise elusive fifth drive (CD/DVD).)

-- 

Steve Szmidt

"They that would give up essential liberty for temporary safety deserve neither liberty nor safety." Benjamin Franklin ----------------------------------------------------------------------- This list is provided as an unmoderated internet service by Networked Knowledge Systems (NKS). Views and opinions expressed in messages posted are those of the author and do not necessarily reflect the official policy or position of NKS or any of its employees.



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