[comp.sys.amiga.hardware] 3000 interleave?

lon.leader@canremote.uucp (LON LEADER) (07/22/90)

   Can anyone tell me how to 'set' or 'force' a specific interleave 
when low-level formatting a harddisk on the 3000?
   Here's why I want to do this.  
   I have just moved up to a 3000 from a 1000.  On the 1000 I was using
a 80 meg. MFM disk with an Adaptec 5500 MFM to SCSI interface and a 
Comspec controller.  This setup was not fast, but it was better than 
floppies.  Tests revealed the optimum interleave for this combo was 
three, yielding a DiskSpeed 3.1 rating of approx. 130-140,000.
   I plugged this drive/interface into the 3000 and did NOT low-level 
format it.  I then partitioned the drive and did an AmigaDOS format.  
DiskSpeed gave a 172,000 rating on this.
   I then used the 3000 to do a low-level format and the drive now 
tested out at 253,000.  I figured from this that the interleave had been
set lower than the three it was before, but I had no way of knowing what
it was.
   I hooked the drive back up to the 1000, and low-level formatted it 
with an interleave of two, then moved it back to the 3000 for 
partitioning and testing.  I got an identical 253,000 rating, so I 
guessed that the interleave arbitrarily choosen by the 3000 software was
two.
   Mad impetuous fool that I am, I then moved the drive back to the 
1000, and low-leveled it with an interleave of one.  Back on the 3000 
for partitioning and testing, I got (are you ready for this?) 436,000 !!
It isn't as fast as the Quantum inside (612,000) but I like it.  It has
worked without any problems for several days.
   Now, does this mean I have to keep my 1000 and Comspec around just in
case I ever want to low-level format this, or another drive?  And the 
question that keeps nagging at me is, what is the interleave on the 
internal Quantum?  Maybe it is only two, and would scream if I could 
lower it to one?
  -=[ Lon ]=-
  lon.leader@canremote.uucp
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