11/73 into 11/03 chassis?

Jerome H. Fine jhfinedp3k at compsys.to
Thu Feb 11 10:57:29 CST 2016

>Jacob Ritorto wrote:

>>On Mon, Feb 8, 2016 at 8:45 PM, Jerome H. Fine <jhfinedp3k at compsys.to> wrote:
>>Specifically, I always use a SEPARATE PC power supply for the hard disk drives.
>Yep, this sounds like exactly where I went wrong.   Two RD32s running
>24/7.  Took it only a couple months to burn out.  In the next incarnation
>of this machine (i.e. if I ever learn to repair power supplies), I'll set
>it up as Jerome describes.
One other point that might help with an RT-11 system which needs the
CPU and specific programs running all the time, but does not require
some of the hard drives all of the time.

Any hard drives which are not the system drive can be powered down
when they are not being used.  If necessary, the device driver which
manages that hard drive is allowed to be UNLOADed and even
REMOVEd while the drive is not being used.  NOTE that this can't
be done with the system hard drive and any other drives attached to
the same controller.

If there is only ONE RQDX3 controller, it might be worth while to
find a second RQDX3 controller for the hard drives which don't
need to be running all the time.

The manner in which the comment that the RD32 hard drives had
been running 24/7 was stated suggested that perhaps they were on
a controller (RQDX3 if I can remember correctly) which did not
also manage the system hard drive.  In that case, RT-11 allows
the device driver to be UNLOADed and REMOVEd and the
hard drive itself can be powered down.  Just reverse the process
when it is necessary to use the hard drive again.

Operating systems such as TSX-Plus are not allowed to do this.
Any Windows system also seems to require hard drives to always
be available - although more recent Windows systems also power
down the hard drives when they are not being used.

Jerome Fine

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