[comp.sys.ibm.pc.hardware] XT HDD controllers with AT machines problems

limrcd@hpsgm2.sgp.hp.com (Richard Lim) (10/01/90)

I have noticed a problem when using XT-class HDD controllers with
AT-class machines (this includes 8086 machines with AT-type BIOSes).

The problem is : The HDD works but any access to the HD is always
preceded by a long pause before the HD starts working (ie the drive
busy lights come on).

Anybody have any explanation for this behaviour or any cures for it?

Ric

pnl@hpfinote.HP.COM (Peter Lim) (10/04/90)

> I have noticed a problem when using XT-class HDD controllers with
> AT-class machines (this includes 8086 machines with AT-type BIOSes).
> 
> The problem is : The HDD works but any access to the HD is always
> preceded by a long pause before the HD starts working (ie the drive
> busy lights come on).
> 
> Anybody have any explanation for this behaviour or any cures for it?
> 
The XT controller must be putting the HD in low power standby mode
when not accessed. My DTC-6280 controller has such a setting on board.
When I enable it, every disk access is preceded with a pause. Diabling
this means that by hard disk light stays on all the time.


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Peter Lim.                     ## .... DON'T PUSH IT !!          >>>-------,
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limrcd@hpsgm2.sgp.hp.com (Richard Lim) (10/04/90)

If that is so, how come it does not have this pause in a real XT?

The XT-controller actually performs faster in an XT.

Hi there, brother Pete!

Back on Notes at last!