two hd's on same IDE channel

  • Thread starter Thread starter Steve James
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S

Steve James

Hi

I have two HD's on the same IDE channel, I think one is faster than the
other (ATA and RPM), will the fastest one be 'held back' by the slowest one
or not ? I have my O/S and program files on the main (fastest) drive and
only use the slower one for storage and the pagefile. (to reduce head
travel)

MTIA

Steve
 
Steve James said:
Hi

I have two HD's on the same IDE channel, I think one is faster than the
other (ATA and RPM), will the fastest one be 'held back' by the slowest one
or not ? I have my O/S and program files on the main (fastest) drive and
only use the slower one for storage and the pagefile. (to reduce head
travel)

MTIA

Steve
Click to expand...

Steve,

Short answer: Yes.
Pagefile should be located on the boot partition. If you only want to
consider speed, it should be on the fastest drive.

Long answer;
My understanding of the IDE bus is that the drives will operate a the speed
(transfer rate) of the slowest device on a channel. RPM rates of the drives
are definitely independent (i.e., A 7200RPM drive always spins at 7200RPM,
even with a 5400RPM drive attached to the same channel).

My practical experience suggests;
1) This generally excludes CD/DVD drives. Although I've experienced some
that seem to "slow-down" a hard drive.
2) Note the term "channel". As you know most computers have on-board IDE
controllers. Most IDE controllers operate 2 channels. (EIDE1/EIDE2 or
Primary/Secondary connections on the MB). My experience dictates for the
best hard drive through-put drives of "like types" (i.e., ATA/33 or ATA100
or ATA133) should be on the same channel.

That said:
Of course, you'll want to check performance at each step including the
current configuration. Find a tool that'll measures drive performance in
each configuration. This way you can measure your results and determine the
optimum connections.
If you have a total of 3 devices; (2 HDD's, 1 CD) I'd connect the slower of
the 2 hard drives on the same channel with the CD and leave the faster drive
by itself. If you have 4 devices; I'd try 1 HD and 1 other device on each
channel.

Articles I've read and my personal experience with pagefile.sys indicates
that it should be located on the boot partition.


Rick
http://www.howtorecoverdata.com
 
"Steve James" said in news:[email protected]:
Hi

I have two HD's on the same IDE channel, I think one is faster than
the other (ATA and RPM), will the fastest one be 'held back' by the
slowest one or not ? I have my O/S and program files on the main
(fastest) drive and only use the slower one for storage and the
pagefile. (to reduce head travel)

MTIA

Steve
Click to expand...

It depends on what motherboard chipset you use. I had a 3+ year-old
Pentium 3 800MHz Slot1 (SECC2) system that used the AOpen AX6BC
motherboard which uses Intel's 440BX chipset. The IDE controller
operated only in single mode; i.e., it would get set for whatever was
the slowest reported device. Doesn't matter what the IDE ports were set
for in the OS. The IDE controller provides 2 channels. For that
system, it was important to match the ATA spec of the devices on each
IDE port and try to NOT mix ATA (hard drive) and ATAPI (CD-ROM drive)
devices on the same port. CD-ROM drives then and still only operate up
to UDMA-33. Putting an UDMA-33/66/100/133 hard drive on the same IDE
channel as, say, a UDMA-33 CD-ROM drive, had the controller operate at
the least-common-denominator of whatever was the slowest device on that
channel so the hard drive would also operate at UDMA-33. So I had my 2
hard drives on IDE0 and the CD-RW and DVD-ROM drives on IDE1 to keep the
slower UDMA-33 CD-type drives off the IDE channel for the faster hard
drives. One of my hard drives was UDMA-100 while the other was UDMA-66
but beyond UDMA-66 there is little real speed increase on end-user host
whose primary function is to run applications rather than operate as a
file server. The interrupted use of the hard drive along with all the
head travel obviates the momentary but short-lived burst mode of the
drive. One drive spun at 7200 RPM and the other at 5400 RPM but that
only affects how long to get to a particular sector on the same track
(so keeping your drive defragmented helps).

So for the old chipsets, they could operate the 2 IDE channels at
different modes (i.e., speeds) but they could only use the lowest
device's mode for all devices on the same channel. One channel could
run in one mode and the other channel could run in a different mode, but
a channel itself could only operate in one mode. Now comes along newer
chipsets that can support multiple concurrent modes on the same IDE
channel. If you visit Intel's web site to look at, say, the hardware
specs for their 845E chipset, the doc for its paired ICH4 (southbridge)
chip notes, "Each IDE device can have independent timings". So you can
have a UDMA-100 hard drive on the same IDE port as a UDMA-33 CD-ROM
drive and the controller will use the best mode to support the highest
transfer rate of each device. There's no harm in configuring the
devices as was needed under the old 1-mode-per-channel chipsets but
there's no point, either. So the better setup now is to have the hard
drives on separate IDE channels (to maximum concurrent bandwidth
capacity for the most used devices) and put the CD-type drives on
whichever channel you want (but preferrably on whichever is not the IDE
channel being used for the Windows "boot" partition, if possible).

Microsoft's terminology regarding which is the boot and system partition
is a bit backwards of common sense. To Microsoft, the "system
partition" is where are located the bootup files and the program located
in the boot sector of the hard drive partition that the bootstrap code
in the MBR uses to start loading the OS. For Windows, this is wherever
are placed the NTLDR, NTDETECT.COM, and BOOT.INI files. The "boot
partition" is wherever is the rest of Windows that gets loaded, like
NTOSKRNL.EXE. So you have boot files on the system partition and system
files on the boot partition. Yeah, go figure. See
http://support.microsoft.com/?kbid=314470.

The system and boot OS partitions can be in the same hard drive
partition and is the typical scenario with Windows installed wholly on,
say, the C: drive. The system BIOS can only read the bootstrap code
from MBR (master boot record, or sector 0) on the first detected
physical hard drive and uses the partition table in that MBR to
determine which is the current active primary partition (which is only
on that same drive since the partition table only has entries for that
drive). The MBR bootstrap program then loads the boot program in first
sector of that partition. Since the system BIOS can only read the MBR
on the first detected physical hard drive, the "system partition" for
Windows must be on that same first hard drive. You can change this
behavior if you replace the standard bootstrap program in the MBR with a
more robust program, like a boot manager (IBM BootManager, Powerquest's
BootMagic, etc.). However, the "boot partition" for the rest of Windows
can be in the same partition on that hard drive, in another partition on
that same hard drive, or in a partition on a completely different hard
drive.

If you have 2 hard drives then you should place pagefiles on BOTH hard
drives. The "boot partition" (where Windows is read from after it got
started) should have a pagefile set to 64KB larger than your system RAM
size but can be larger. Then configure a pagefile on the other hard
drive of the same size or larger, typically 1.5 to 2.5 times your RAM
size. Windows will detect that a pagefile exists on a hard drive other
than its boot partition and give it higher priority for use. To reduce
fragmentation of the pagefiles, set their min and max size to the same
value. The defrag program included in Windows will not defrag the
pagefiles, so you need to use the trick of rebooting into Recovery
Console mode to delete the pagefiles (after already having defragged the
drives) so they get recreated on Window startup. Some 3rd party
defraggers, like Diskeeeper and PerfectDisk, will defrag the
pagefile(s). Some folks will even create a separate partition on the
non-boot partition hard drive just for that pagefile to keep it from
getting fragmented with data and applications that normally show up on
the other hard drive. I've never bothered going that extreme but then I
regularly defrag my drives. The pagefile being 1 piece might have a
tiny performance advantage to a pagefile sliced into 3 or 5 pieces but
that's insignificant to the performance loss if the pagefile was sliced
into hundreds of pieces.

Even if the drives spin at different speeds, you'll want to allocate a
pagefile on the non-boot partition to allow Windows to page out virtual
memory while it can still concurrently read/write files on its own boot
partition. If the hard drives are UDMA-66 or higher, it really doesn't
matter that the primarily used pagefile on the non-boot partition is
spec'ed to use a slightly slower burst mode. However, once you get a
difference of UDMA-100 (nothing really for UDMA-133) against UDMA-33 for
2 hard drives, and especially if the UDMA-33 spins at 5400 RPM and the
UDMA-100 drive spins at 7200 RPM, you'll probably want to forego using a
pagefile on that slower non-boot partition hard drive.
 
*Vanguard* said:
....same IDE channel....
....pagefile....separate partition.....
Click to expand...

Hey, if you wanna write more stuff, I'm takin' notes!
:-)

*TimDaniels*
 
"Steve James" said in news:[email protected]:

It depends on what motherboard chipset you use. I had a 3+ year-old
Pentium 3 800MHz Slot1 (SECC2) system that used the AOpen AX6BC
motherboard which uses Intel's 440BX chipset. The IDE controller
operated only in single mode; i.e., it would get set for whatever was
the slowest reported device. Doesn't matter what the IDE ports were set
for in the OS. The IDE controller provides 2 channels. For that
system, it was important to match the ATA spec of the devices on each
IDE port and try to NOT mix ATA (hard drive) and ATAPI (CD-ROM drive)
devices on the same port. CD-ROM drives then and still only operate up
to UDMA-33. Putting an UDMA-33/66/100/133 hard drive on the same IDE
channel as, say, a UDMA-33 CD-ROM drive, had the controller operate at
the least-common-denominator of whatever was the slowest device on that
channel so the hard drive would also operate at UDMA-33.
Click to expand...

Ummmm, that had nothing to do with the 2nd device, the 440BX chipset only
supports up to ATA33, there is no possible way for any device in any
possible configuration to run any faster than ATA33 from it's onboard
controller.

So for the old chipsets, they could operate the 2 IDE channels at
different modes (i.e., speeds) but they could only use the lowest
device's mode for all devices on the same channel. One channel could
run in one mode and the other channel could run in a different mode, but
a channel itself could only operate in one mode. Now comes along newer
chipsets that can support multiple concurrent modes on the same IDE
channel.
Click to expand...

That happened around 1994, IIRC.
 
Hi

I have two HD's on the same IDE channel, I think one is faster than the
other (ATA and RPM), will the fastest one be 'held back' by the slowest one
or not ? I have my O/S and program files on the main (fastest) drive and
only use the slower one for storage and the pagefile. (to reduce head
travel)

MTIA

Steve
Click to expand...
 
kony said:
Ummmm, that had nothing to do with the 2nd device, the 440BX chipset
only supports up to ATA33, there is no possible way for any device in
any possible configuration to run any faster than ATA33 from it's
onboard controller.
Correct.


That happened around 1994, IIRC.
Click to expand...

You do indeed RC.

The short answer is: Put any drive wherever you want to put it. As long as
the boot drive is primary master the rest doesn't matter so's you'd notice.
 
Mike said:
On older motherboards the I/O speed will be the protocol of the
slower device; PIO mode is worst case. This was usually a problem
with a hard drive and a CDROM on the same cable. Some say that newer
boards with dual fifo can run different protocol for each device. I
have not tried any tests to verify this.
Click to expand...

*I* have. Pretty much any board made after around 1994 will run each drive
at or close to it's rated speed (or the rated speed of the IDE channel,
whichever is greater) regardless of whatever else is on the channel.

I just published the results of a test I did to prove this in this NG about
six or so weeks ago.
 
OK Thanks for info, though a few different views not sure I am certain which
way to go

Steve
 
"kony" said in news:[email protected]:
Ummmm, that had nothing to do with the 2nd device, the 440BX chipset
only supports up to ATA33, there is no possible way for any device in
any possible configuration to run any faster than ATA33 from it's
onboard controller.
Click to expand...

And hard drives started at UDMA-33, huh? Forgot about the older PIO
modes?
 
"kony" said in news:[email protected]:

And hard drives started at UDMA-33, huh? Forgot about the older PIO
modes?
Click to expand...


Forget? No, I meant nothing more than I wrote... at least the way it read
it me, it seemed as though you were implying that this was causing the
hard drives to drop down to ATA33 mode, which was the highest mode they
could support anyway. If you're claiming that PIO mode ATAPI devices will
slow down the BC chipset, I won't refute that as I don't recall enough
first-hand experiences trying to run PIO mode as late as the BX chipset.
 
"kony" said in news:[email protected]:
Forget? No, I meant nothing more than I wrote...
Click to expand...

Okay, reread your reply and you're right that UDMA-33 was the highest
mode supported by Intel's 440BX chipset. I just wanted to make sure the
it was understood that all modes (PIO and UDMA) might mix okay, might
not, and I wasn't sure about the 440BX ... until today when I finally
decided to look.

I got rid of my last Intel 440BX box a little while ago. As I recall,
that one was configured with the ATA devices (hard drives) on IDE0 and
the ATAPI devices (CD-RW & DVD-ROM) on IDE1. Over the lifetime of this
mobo, it first started out with really old drives scavanged from even
older boxes and just ran DOS and then SCO and, I think, Solaris x86, so
it did have some old PIO-only mode hard drives. About when Windows got
put on it was when the drives were updated. In fact, because the mobo's
IDE ports only supported up to UDMA-33, I put in a Promise Ultra100 to
better support the UDMA-66 & -100 drives and so each had its own channel
(which also meant the ATAPI devices could each be placed on their own
channel on the mobo's IDE ports).

I'm not sure the ATA and ATAPI devices really had to be separated on
different channels for the Intel 440BX. I think that was how it was
first configured because it was unknown at the start if independent
timing was supported per channel; not everything was on the Internet
back then for ease in lookup. I had another coworker using the box who
kept claiming the ATA & ATAPI devices should be separated on different
channels and since it didn't hurt I just let him have his way. Although
we don't have that old 440BX box anymore, I finally decided to check on
my break. Went to Intel and dug around for awhile and found for the
82371AB PCI-to-ISA chip (southbridge that provides the IDE channels),
"Integrated IDE Controller: Independent timing of up to 4 drives." Aha!
I was right all along. Oh well, running in the
lowest-common-denominator hardware configuration didn't hurt, either.

Thanks for participating. Always something to learn in the newsgroups.
 
"kony" said in news:[email protected]:
http://www.storagereview.com/guide2000/ref/hdd/if/ide/confTiming.html
Click to expand...
http://www.storagereview.com/guide2000/ref/hdd/if/ide/confPerformance.html

Thanks for the links. Ever visit www.pcguide.com who this link is
referencing (in a static copy rather than a link)? After a year or
more, it sure would be nice if www.pcguide.com someday fixes their
search function to it works again. Having to drill around through the
index takes a lot longer. I used to go there a lot to look up some info
but using Google is often faster going through the matches than having
to drill through pcguide.com. They/he really needs to fix his web site,
or move back to a web host provider that includes Frontpage extensions.
Unfortunately it doesn't look like it is being maintained to be kept up
to date. Alas, twas a good reference site.
 
On Wed, 10 Mar 2004 13:32:51 -0600, "*Vanguard*"

"Integrated IDE Controller: Independent timing of up to 4 drives." Aha!
I was right all along. Oh well, running in the
lowest-common-denominator hardware configuration didn't hurt, either.
Click to expand...


Prior to the 440BX, for example early socket 7, boards supported IDT
(independent device timing) but what I'm less certain of is when, if ever,
the controllers were able to run one device in PIO mode while the other on
same channel is in DMA/UDMA mode... I was under the impression that both
modes couldn't be supported simultaneously per channel, but then I've
seen at least a couple of posts claiming IDT makes that possible... never
bothered testing that myself since I've never had any desire to run PIO
drives after there were UDMA alternatives.
 
Good references. However, note the "Copyright 1997-2000......" at the bottom
of the page. So, what that page refers to as "Three years old" is in fact
seven years old. Also, it says "Most new motherboards......." You can read
that as "All new motherboards...." fairly safely.
Click to expand...


Yep, it's pretty old by today's standards. Most PIO drives don't even
work anymore unless they were just sitting on a shelf/unused.
 
kony said:
On Wed, 10 Mar 2004 13:32:51 -0600, "*Vanguard*"




Prior to the 440BX, for example early socket 7, boards supported IDT
(independent device timing) but what I'm less certain of is when, if
ever, the controllers were able to run one device in PIO mode while
the other on same channel is in DMA/UDMA mode... I was under the
impression that both modes couldn't be supported simultaneously per
channel, but then I've seen at least a couple of posts claiming IDT
makes that possible... never bothered testing that myself since I've
never had any desire to run PIO drives after there were UDMA
alternatives.
Click to expand...

I've tested it, althought with my relatively new nForce2 Ultra 400 board,
and having an old 120MB drive in PIO mode running alongside a modern drive
running UltraDMA mode 5 on the same channel made virtually no difference to
access times of the modern drive.
 
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