View Full Version : Fastest interleave for ST-225 drive

August 28th, 2006, 06:06 AM
So, I heard, that factory-set interleave 3 is the slowest.
I need the best one, maybe someone know wich wold be the best?

August 28th, 2006, 06:35 AM
The drive doesn't care what interleave you use. The computer does.

Interleave controls the numbering of sectors in a track. An interleave of 1 means that the sectors are numbered sequentially, so the machine and controller have to be fast enough to read sectors as quick as the heads pick them up.

Other interleave factors space the sectors out so that you get an extra rotation on the disk platter before the next sector is available to read. This is needed for slower machines, who can't take data at the full rate the drive can provide it at when using an interleave of 1.

So for PCs and XTs and similiarly slow machines, try an interleave of 2 or 3. For ATs and faster machines with the 16 bit interface try 1. You need to benchmark to be certain.

October 28th, 2006, 10:46 AM
I am low-level formatiing my Seagate ST-4096 80mb drive with Western Digital Disk Manager "OnTrack" software.

The manual says:"The recommended interleave for drives with an average access time equal to or faster than 40 milliseconds is 4;the hard disk with an average access time slower than 40 ms has an interleave of 3. The default interleave is 4."

My average access time is 28ms. I have done speed index tests with Norton and the fastest yet is with the Interleave of 1 (2 is the same).
With an interleave of 3 or 4, it gives a slower speed index.

What is the best interleave for this 80286-AT machine?

October 28th, 2006, 12:05 PM
The best interleave to use is a function of the machine and controller, not the drive. With a good controller you can use an interleave of 1, which would be the best.

Try 1 and 2. Measure both. Then take the fastest.

My old 4.77 XT with the original 10MB drive uses an interleave of 5. I tried 2 - 6 using Gibson Research's SpinRite, and 5 came out the best. That machine is on an old 8 bit interface - an AT class machine with a 16 bit interface should do much better.

October 28th, 2006, 12:45 PM
Reminds me of those 10 hour "Norton Utilities Defrag" I would do on my 1991 Gateway 386/25. That drive lasted me a long time. It did get to where you would have to warm it up first before doing any writes to the drive. If you wrote on it when cold, you couldn't read the info after it warmed up.

October 28th, 2006, 01:27 PM
The old norton packages (4? 5?) also had the program 'Calibrate' that could test and change to best interleave.

October 28th, 2006, 02:28 PM
Yes indeed, I was always a BIG Norton Utilities fan. Not lately though. When I purchased my Dell E1705, I ordered Norton System Works just because it was inexpensive! I haven't even installed it yet and it's been sitting here for over 6 months.

Just not the same!

As we all know, "you" really don't need Norton anymore. Winders comes with defrag already. Every ISP provides antivirus, antispyware, antianti.

the xt guy
November 1st, 2006, 01:46 PM
The controller you attach the drive to has an effect on the Drive Interleave. For example, I've read that the original 10MB hard drive in the IBM 5160 came with the Interleave set to "6:1" with the IBM controller, and that it could be reset to "5:1", which would give a slight increase. If however, you replaced the slow IBM controller with the Western Digital xt-gen controller card, the drive could now accept an Interleave of "3:1".

I have both an IBM 5150 and an XT clone (8 mhz) with ST-225 drives and they have the WD xt-gen controller. The best Interleave tests out to "3:1".

I think this is about the best Interleave you are going to get with an ST-225 unless you've got a very unusual controller.

A SCSI drive works much faster in an XT than a MFM/RLL drive. I have another 5150 with a 40mb. SCSI drive and controller and the Interleave on it is 1:1. It tests over 500k transfer speed (vs. about 149k on the ST-225 with 3:1 Interleave.)