Re: UPS devices for PDP11 - VMS

This is a discussion on Re: UPS devices for PDP11 - VMS ; From: "Julian Wolfe" >Okay, I'm building this 11/23 system, and I'm thinking about those wonderful >RL02s and the possibility of a power failure and those heads crashing into >the disk. I'm damn worried. Well it never hurts to be conservative, ...

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Thread: Re: UPS devices for PDP11

  1. Re: UPS devices for PDP11

    From: "Julian Wolfe"

    >Okay, I'm building this 11/23 system, and I'm thinking about those wonderful
    >RL02s and the possibility of a power failure and those heads crashing into
    >the disk. I'm damn worried.


    Well it never hurts to be conservative, but I've had the power cut out on
    my RLs plenty of times with no ill effects. DEC did worry about this kind
    of thing and designed accordingly (RK05s had NiCads to pull the heads out
    when the power dies).

    John Wilson
    D Bit
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  2. Re: UPS devices for PDP11

    John Wilson wrote in message news:<200411231634.iANGYSp27695@dbit.com>...
    > From: "Julian Wolfe"
    >
    > >Okay, I'm building this 11/23 system, and I'm thinking about those wonderful
    > >RL02s and the possibility of a power failure and those heads crashing into
    > >the disk. I'm damn worried.


    RL02's are really, really sturdy drives. It's not impossible to crash
    the heads but it's almost always due to a physically damaged (bent) pack.

    > Well it never hurts to be conservative, but I've had the power cut out on
    > my RLs plenty of times with no ill effects. DEC did worry about this kind
    > of thing and designed accordingly (RK05s had NiCads to pull the heads out
    > when the power dies).


    RL02's use a capacitor for the AC-power-failed retract.

    Some other drives use the drive motor as a generator in case of a power
    fail to drive the head retract.

    Tim.

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