Method and apparatus for detecting component removal while operating in a battery backup mode

• US 7,962,776 B2
• Filed: 10/14/2007
• Issued: 06/14/2011
• Est. Priority Date: 10/14/2007
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Ohrazda, Joseph Dean, Juarez, Larry, Groff, Steven Mark, Qiu, Kenny Nian Gan
• Primary Examiner(s): Stoynov; Stefan
• Application Number:
  US11/872,017
• Publication Number:
  US 20090100282A1
• Time in Patent Office: 1,339 Days
• Field of Search: 713/300, 713/340, 307/46, 307/66, 320/107, 320/116, 320/126, 365/226, 711/112, 714/14, 714/22
• US Class Current: 713/340
• CPC Class Codes: G06F 1/28 Supervision thereof, e.g. detecting power-supply failure by out of limits supervision

Abstract

A method to detect component removal while operating in a battery backup mode, comprising providing power from a battery backup unit (BBU) to a control card memory device, and measuring the current drawn by the control card memory device. If the current drawn by the control card memory device is less than or equals a pre-determined disconnect current, the method determines if a BBU release pin has been asserted. If the BBU release pin has been asserted, the method encodes in an event log a battery backup removal event. If the BBU release pin has not been asserted, the method encodes in the event log a control card removal event.

Claims

1. A method to detect component removal while operating in a battery backup mode, comprising the steps of:

providing a control card comprising a control card memory device, wherein said control card is interconnected to a battery backup unit (BBU) comprising a processor, event log, a BBU release pin, and one or more batteries;

providing power from said battery backup unit to said control card memory device; and

measuring the current drawn by said control card memory device;

generating an early power off warning signal by said power supply;

providing said early power off warning signal to said processor;

if the current drawn by said control card memory device is less than or equals a pre-determined disconnect current, determining if said BBU release pin has been asserted;

if the current drawn by said control card memory device is less than or equals said disconnect current and if said BBU release pin has been asserted, encoding in said event log a battery backup removal event.

2. The method of claim 1, further comprising the step of encoding in said event log a control card removal event if the current drawn by said control card memory device is less than or equals said disconnect current and if said BBU release pin has not been asserted.

3. The method of claim 1, further comprising the steps of:

determining if the current drawn by said control card memory device is greater than or equal to a pre-determined nominal current;

if the current drawn by said control card memory device is greater than or equal to said pre-determined nominal current, encoding in said event log a nominal current event.

4. The method of claim 3, further comprising the steps of:

determining if the current drawn by said control card memory device is less than said nominal current but greater than or equal to a pre-determined fault current;

if the current drawn by said control card memory device is less than said nominal current but greater than or equal to said pre-determined fault current, encoding in said event log a fault current event.

5. The method of claim 4, further comprising the steps of:

determining if the current drawn by said control card memory device is less than said fault current but greater than said pre-determined disconnect current;

if the current drawn by said control card memory device is less than said fault current but greater than said pre-determined disconnect current, encoding in said event log a memory device failure event.

6. The method of claim 5, further comprising the steps of:

continuing to measure the current drawn by said control card memory device.

7. The method of claim 4, wherein said battery backup unit comprises a non-volatile BBU memory device, said method further comprising the steps of:

establishing said nominal current;

establishing said fault current;

establishing said disconnect current;

encoding said nominal current in said BBU memory device;

encoding said fault current in said BBU memory device;

encoding said disconnect current in said BBU memory device.

8. The method of claim 7, further comprising the step of encoding said event log in said non-volatile BBU memory device.

9. An article of manufacture comprising a processor, an event log, one or more batteries, and a computer readable medium having computer readable program code disposed therein to provide power to a control card memory device disposed in an interconnected control card, wherein said article of manufacture is interconnected with a power supply interconnected to said control card, the computer readable program code comprising a series of computer readable program steps to effect:

providing power to said control card memory device; and

measuring the current drawn by said control card memory device;

receiving an early power off warning signal from said power supply;

if the current drawn by said control card memory device is less than or equals a pre-determined disconnect current, determining if said BBU release pin has been asserted;

if the current drawn by said control card memory device is less than or equals said disconnect current and if said BBU release pin has been asserted, encoding in said event log a battery backup removal event.

10. The article of manufacture of claim 9, said computer readable program code further comprising a series of computer readable program steps to effect encoding in said event log a control card removal event if the current drawn by said control card memory device is less than or equals said disconnect current and if said BBU release pin has not been asserted.

11. The article of manufacture of claim 9, said computer readable program code further comprising a series of computer readable program steps to effect:

determining if the current drawn by said control card memory device is greater than or equal to a pre-determined nominal current;

operative if the current drawn by said control card memory device is greater than or equal to said pre-determined nominal current, encoding in said event log a nominal current event.

12. The article of manufacture of claim 11, said computer readable program code further comprising a series of computer readable program steps to effect:

determining if the current drawn by said control card memory device is less than said nominal current but greater than or equal to a pre-determined fault current;

if the current drawn by said control card memory device is less than said nominal current but greater than or equal to said pre-determined fault current, encoding in said event log a fault current event.

13. The article of manufacture of claim 12, said computer readable program code further comprising a series of computer readable program steps to effect:

determining if the current drawn by said control card memory device is less than said fault current but greater than said pre-determined disconnect current;

if the current drawn by said control card memory device is less than said fault current but greater than said pre-determined disconnect current, encoding in said event log a memory device failure event.

14. The article of manufacture of claim 13, said computer readable program code further comprising a series of computer readable program steps to effect continuing to measure the current drawn by said control card memory device.

15. A data storage system, comprising a control card comprising a memory device, and a battery backup assembly interconnected to said control card, said battery backup assembly comprising:

a processor;

an event log;

one or more battery charging units;

one or more rechargeable batteries interconnected to said one or more battery charging units;

an output power bus interconnected to said one or more rechargeable batteries;

a current measuring circuit interconnected to said output power bus and to said processor;

a non-volatile memory;

a nominal current value encoded in said non-volatile memory;

a fault current value encoded in said non-volatile memory;

a disconnect current value encoded in said non-volatile memory;

wherein said event log is encoded in said non-volatile memory.