MAXTOR XT4170 with WD1007 Controller (& SpeedStore)

[J.T. Conklin]

In article <10375 at rls.UUCP> randy at rls.UUCP (Randall L. Smith) writes:
>In article <1989Nov24.025335.20233 at ddsw1.MCS.COM>, karl at ddsw1.MCS.COM (Karl Denninger) writes:
>> NO!  Doing that makes the system quite a bit slower than if you leave it at
>> the real physical parameters!   You see, the controller has to remapping if
>> you set things up like that.  

>But Karl, that is the function of the WD1007-WA2.  Dos and earlier versions
>of Unix cannot (with native drivers) access those extended address ranges. 
>Since all the computing and remapping is done on the controller, this
>should not be slower.

Even if translation could be done instaneously, disk performance will
be seriously impaired.

The disk arm scheduling algorithm in the device driver has to know
about the physical disk geometry for optimum performance.  Typically
the scheduling algorithm assumes that track n is next to tracks n-1
and n+1.  A translating controller invalidates this assumption.

    --jtc

-- 
J.T. Conklin
	...!{uunet,ubc-cs}!van-bc!jtc, jtc at wimsey.bc.ca