Very Computer

I've read all the posts about problems with Promise and other add-on Ultra DMA EIDE
disk controllers, but I have yet to see anywhere whether you can run the new Ultra DMA
EIDE disk drives on an integrated disk contoller like the one on my ASUS TXP4 motherboard
with the Intel 430TX chipset.  I guess I have two questions:

1. If I buy one of the new WD disks with Ultra DMA, will it be fully supported at the
     Ultra DMA speed of 33Mbps?

2. Since the answer to #1 is probably "no", I also want to know if  the 2.0.3x kernels
will
    recognize an Ultra DMA drive at all, as has been suggested in previous posts, and is
    implied on the RedHat support website?  Is there a BIOS setting or boot parameter that

    must be used when running Ultra DMA disks, such as the WD 4.3GB drives?

I'm running RedHat 4.2 with the 2.0.30 kernel.

Please respond via email as well as in the newsgroup, since I'm planning on buying one of
these
WD drives in the next couple of days.

Thanks!

--
Ed Skladany    Hopewell, NJ

http://pluto.njcc.com/~eds

Quote:> will
>     recognize an Ultra DMA drive at all, as has been suggested in previous posts, and is
>     implied on the RedHat support website?  Is there a BIOS setting or boot parameter that

>     must be used when running Ultra DMA disks, such as the WD 4.3GB drives?

> I'm running RedHat 4.2 with the 2.0.30 kernel.

> Please respond via email as well as in the newsgroup, since I'm planning on buying one of
> these
> WD drives in the next couple of days.

Greetz,
Joop.

-----------------------------------------------------------------------
 Joop Bollen.   Nuts & Bolts Department,   Nomadis Systems, Holland

 PGP Fingerprint   F3 AB 1C A2 AE BE 52 3B  16 90 4A ED AB DA 63 B3
 PGP Key On A Friendly PGP_Key_Server In Your Neighbourhood.
 Please Remove *** From Signature Before Replying.
------------------------------------------------------------------------

Joop,

Thanks for the response, but I'm well aware of the SCSI/IDE tradeoff and want to continue EIDE.

My main question still needs answering, though.  Will an Ultra DMA disk be recognized by Linux,

or will I have to set some BIOS or kernel parameters?

I dont have a UDMA drive, so I dont know if Linux will handle it, but I can
tell you (I work at a computer store) that a quality TX chipset board will
support UDMA. Best thing to do is to ask whoever you're buying it from. As
for the board you already have, hop on over to the Asus web page and check..

Also, remember that 33/Mbps is -maximum burst- speed, not average throughput

--
----------------------------------------------------------------------------
-----------------
It is by Caffeine alone that I set my mind in motion.
It is by the beans of Java that my thoughts acquire speed.
The hands acquire shakes; the shakes become a warning.
It is by Caffeine alone that I set my mind in motion.

Scott Alfter (salfter at eye bee emm dot net)
http://people.delphi.com/salfter

Very true, I have had horrible experiences from Maxtor drives for years now.

--

5, rue de la Raillere
65110   Cauterets       France.

I try to write a udma driver for the via chipset .There is a lot of
improvement in drive speed. see
http://www.pyreneesweb.com/Udma/udma.html.

There another site dealing with Intel chipset , but i don't remember it
exactly.
Michel Aubry.
--

5, rue de la Raillere
65110   Cauterets       France.

Quote:>2. Since the answer to #1 is probably "no", I also want to know if  the 2.0.3x kernels
>will
>    recognize an Ultra DMA drive at all, as has been suggested in previous posts, and is
>    implied on the RedHat support website?  Is there a BIOS setting or boot parameter that

>    must be used when running Ultra DMA disks, such as the WD 4.3GB drives?

>I'm running RedHat 4.2 with the 2.0.30 kernel.

The kernel sets up the drives automatically.
--

http://www.stack.nl/~hanwen       | http://www.stack.nl/~hanwen/lilypond/

net effect.  ie.. If you will never be using more than 1 drive or if you have a
tight
budget buy IDE, if you have money to spare and will be using 2 or more drives
buy SCSI.
PS : I have 3 IDE drives ( 2 Quantum Fireballs and a 24X CD-ROM )

--
Jim Zubb

[...]
: The difference between SCSI and IDE still shows up when you have
: 2 or more drives on your system.   ie.. A machine with 4 IDE drives
: is noticeably slower than a similar system with 4 SCSI drives.
: I could spend the next 500 lines detailing the technical reasons
[...]

I would be interested in those reasons.  Also, does UltraDMA support
gather reads and scatter writes?

Tom Payne

: well, dont expect any miracles from this UDMA drives.
: Its as much a marketing hype as anything.

nonsense.  the faster transfer rate is not a major win, but the
CRC16 _is_.  much better than parity on SCSI, actually.

: if you want fast drives then there are two determining factors:
: 1. CPU overhead.
: IDE has ALOT of cpuoverhead. For fast disks, buy SCSI.

you do not know what you're talking about.

: 2.rotationspeed.
: The faster it turns, the faster you access your data.

bandwidth is proportional to rotational speed * density.
fact is that my new 8.4G IDE disk probably sustains better
bandwidth than your old SCSI because of the density thing...

: Buy the disk with the fastest rotationspeed you can afford.
: all other considerations (including brand) are not worth looking at.

bullshit.

: : The difference between SCSI and IDE still shows up when you have
: : 2 or more drives on your system.   ie.. A machine with 4 IDE drives

not really.  you have to be generating heavy load on all the disks
before you really see IDE contention as a problem.  of course, striping
with md is an excellent way to generate that kind of load.

: : is noticeably slower than a similar system with 4 SCSI drives.

I have lots of ide and scsi systems.  the critical factor is whether
the drives are relatively new, just because density has increased so
nicely in the past year.

: : I could spend the next 500 lines detailing the technical reasons

it doesn't take that much space.  here are some simple facts:

0. THERE IS NO "EFFICIENCY" DIFFERENCE!  busmastering IDE works fine.

1. SCSI disks are significantly more expensive than IDE: nice SCSI
   still costs around $.10/MB, whereas good IDE is around $.045/MB.

2. your motherboard already has a good IDE controller,
   saving between $120 and 350 for a decent SCSI controller.

3. SCSI disks share their bus better, offer greater variety in types
   of devices, and support more devices at once.

4. current commodity IDE disks sustain 8-12 MB/s, and sit on a bus that
   peaks at 16 or 33 MB/s.  good SCSI disks sustain 9-19 MB/s,
   and sit on a bus that can be 10 MB/s, is often 20, sometimes 40 MB/s.

5. the SCSI interface is generally superior, allowing split transactions
   and device-level reordering.  this does NOT make a significant difference,
   probably because IDE drives do readahead, write-behind and Linux does
   sort the request queue.

6. good SCSI disks have _double_ the MTBF of good IDE disks.  of course,
   your power supply has one tenth the MTBF of even an IDE disk...

: I would be interested in those reasons.  Also, does UltraDMA support
: gather reads and scatter writes?

non-ultra DMA does scatter/gather, of course.  the Ultra stuff just
adds the 33 MB/s rate and support for CRC16 error detection.

in short, there are a limited number of places where SCSI makes sense,
and they do not include the typical desktop user.  even a high-end user,
with, say, two 8G IBM UIDE disks might be better off without SCSI.

if you _do_ get SCSI, please don't get a controller any lower-end than
a Buslogic Flashpoint or an NCR/Sym 875-based card.  they're both great
and around $120, but cheaper cards will disappoint you...

regards, mark hahn.