Monthly Archives: March 2015

Resistor (2)

Resistor adalah komponen elektronika yang berfungsi untuk menghambat atau membatasi aliran listrik yang mengalir dalam suatu rangkain elektronika. Sebagaimana fungsi resistor yang sesuai namanya bersifat resistif dan termasuk salah satu komponen elektronika dalam kategori komponen pasif. Satuan atau nilai resistansi suatu resistor di sebut Ohm dan dilambangkan dengan simbol Omega (Ω). Sesuai hukum Ohm bahwa resistansi berbanding terbalik dengan jumlah arus yang mengalir melaluinya. Selain nilai resistansinya (Ohm) resistor juga memiliki nilai yang lain seperti nilai toleransi dan kapasitas daya yang mampu dilewatkannya. Semua nilai yang berkaitan dengan resistor tersebut penting untuk diketahui dalam perancangan suatu rangkaian elektronika oleh karena itu pabrikan resistor selalu mencantumkan dalam kemasan resistor tersebut.

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Kapasitor adalah komponen elektronika yang dapat menyimpan dan melepaskan muatan listrik dalam waktu tidak tertentu. Berbeda dengan batere atau akumulator, kapasitor menyimpan dan melepaskan muatan tanpa terjadi perubahan kimia dalam kapastor tersebut. Kapasitor dibangun dari 2 buah plat yang dipisahkan oleh bahan dielektrik. Bahan yang digunakan sebagai dielektrik dalam suatu kapasitor ada beberapa jenis diantaranya udara, keramik, kaca, milar, mika, kertas, tantalum dan elektrolit. Berdasarkan dielektrikumnya kapasitor dibagi menjadi beberapa jenis kapasitor, antara lain:

  • Kapasitor Kertas
  • Kapasitor Keramik
  • Kapasitor Milar
  • Kapasitor Mika
  • Kapasitor Film
  • Kapasitor Elektrolit
  • Kapasitor Tantalum

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Resistor (1)

Resistor tetap (Fix Resistor) adalah resistor yang nilai hambatannya tidak dapat diatur (tetap), sedangkan resistor variabel adalah resistor yang nilai resistansinya dapat diatur.  Dari kedua jenis resistor ini memiliki beberapa varian lagi yang disesuaikan dengan tujuan atau fungsi penggunaannya.

Resistor Tetap (Fix Resistor)

Resistor Tetap,fix resistorResistor Tetap (Fix Resistor)

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Handling Watchdog Resets


Handling watchdog resets

KB ID: 3013539 Version: 8.0 Published date: 01/15/2015 Views: 8592



  1. What is a watchdog reset?

A watchdog is an independent timer that monitors the progress of the main controller running Data ONTAP. Its function is to serve as an automatic server restart in the event the system encounters an unrecoverable system error.

The watchdog implemented by NetApp uses a two-level timer with different actions associated with each level of time.

  • Level 1: Timeout: The storage appliance attempts to panic and dump the core in response to a non-maskable interrupt. Once a L1 watchdog is successfully issued, the system returns to service and a core file is written, allowing NetApp to determine the root cause of the hang. A L1 watchdog is issued if the timer is not reset within 1.5 seconds.
  • Level 2: Reset: The storage appliance resets through a hard reset signal sent from the timer. A L2 watchdog is issued if the watchdog timer is not reset within two seconds after the L1 watchdog.

It is not necessary to ‘recover’ from a watchdog timeout or watchdog reset, as both of these events are recovery mechanisms for other failures. The objective instead is to identify the failure(s) that caused the watchdog event.

  1. What is the appropriate response to a watchdog timeout (L1 Watchdog Event)?
    A watchdog timeout should be treated just like any other system panic. The associated backtrace and/or the core should be analyzed for the possible root cause(s). A giveback should be performed if necessary.
  2. What is the appropriate response to a watchdog reset (L2 Watchdog Event)?

If the storage appliance receives a single watchdog reset, in general, no action needs to be taken as the condition causing the watchdog reset most often is a transient issue and would have been cleared by the reset process. A giveback should be performed if necessary, and the appliance should be monitored for repeat occurrences.
If a storage appliance takes multiple watchdog resets, look for previously logged errors associated with the CPU, motherboard, memory or I/O cards.

  1. Data to be collected to help diagnose the cause of a watchdog reset:
  • AutoSupports
  • Console logs before, during, and after the watchdog event (if possible)
  • ssram log (/etc/log/ssram/ssram.log or /mroot/etc/log/ssram/ssram.log) – FAS62xx only
  • On systems with a service processor: – system sensors – events all – system log – sp status -d

Note: No hardware should be replaced unless the root cause is a hardware issue.



NetApp provides no representations or warranties regarding the accuracy, reliability, or serviceability of any information or recommendations provided in this publication, or with respect to any results that may be obtained by the use of the information or observance of any recommendations provided herein. The information in this document is distributed AS IS, and the use of this information or the implementation of any recommendations or techniques herein is a customer’s responsibility and depends on the customer’s ability to evaluate and integrate them into the customer’s operational environment. This document and the information contained herein may be used solely in connection with the NetApp products discussed in this document.