Test type・Functional testing of RAS
- 1. Check the operation and quality of important RAS functions with dedicated tests
- 2. What is the function of RAS in the first place?
- 3. The reliability of embedded systems ( Reliability )
- 4. Embedded System Availability ( Availability )
- 5. Built-in system of maintenance (Servicea Bility )
- 6. Maintainability features and tests for cause investigation
- 7. Maintainability features and tests for troubleshooting
Built-in system of maintenance (Servicea Bility )
When considering the maintainability of embedded systems, it is easier to understand if you divide them into two parts. One is a function for investigating the cause of a defect , and the other is a function for dealing with a defect . You can test the maintainability of this maintainability function by checking the contents if it is clearly stated in the requirement specifications. However, when the maintainability function is not clearly stated in the required specifications, it is necessary to confirm the presence or absence of the maintainability function and whether it can be used by a maintainability test.
Maintainability features and tests for cause investigation
When an embedded system causes a problem in the market, the difficulty of dealing with it depends on whether the problem can be reproduced in-house or not. If the conditions under which the problem occurs are clearly known and can be reproduced in-house, various investigation methods can be used, so the cause can be found in a short time, and software defects can be fixed and the effects can be confirmed quickly. However, unfortunately, in the embedded system market problem, it is often the case that the problem cannot be reproduced in-house because the conditions of occurrence are unknown or it depends on the operating environment of the device .
In preparation for such cases, embedded systems are often equipped with a function to record information for investigating the cause of a malfunction . Generally, it is a log function called error log and operation log , and a kernel dump function that saves the state when a problem occurs in the OS. The error log includes a counter log that records what kind of error occurred and how many times, and an event log that sequentially records what kind of error occurred at what time and minute . Kernel dump is a standard feature of Unix-like systems that captures various states of the kernel when a problem occurs.
These information for investigating the cause are (1) collected as information indicating the state until just before the problem occurs, ( 2) when the problem occurs, the information collected up to that point is recorded somewhere, and ( 3) the information is a software engineer. of up to hand deliver is a by ④ software engineer its information and analysis , useful to investigate the cause of the first problem.
In the maintainability function test for investigating the cause, when a problem occurs, it is confirmed that the functions (1) to (3) operate as planned and the information is safely delivered to the software engineer . For example, if the error log is recorded in the DRAM and the contents of the DRAM are erased by automatic restart immediately after the problem occurs, the function (2) may not work properly. In the maintenance function test, we will check various situations to see if such a situation occurs.
Maintainability features and tests for troubleshooting
When a problem occurs in the market, it is important to investigate the cause, but first of all, it is more important to restore the function of the product in the market and resume the service to the end user . It is best if the device’s own auto-recovery function works and the function is restored, but in some cases it is not. In such cases, remote maintenance operations such as attempting recovery processing by remotely operating the equipment on the market from the management center are often performed. Such a remote maintenance function becomes a maintainability function for troubleshooting.
Of course, it is premised that the functions required for remote maintenance are installed in the device, but in general, (1) check the device status, ( 2) rewrite the device settings, ( 3) rewrite the device firmware, and ( 4) restart the device. In many cases, it is equipped with functions such as
These remote maintenance features are not directly related to the services the device provides to the end user and are not used when the device is operating without problems. In other words, it is a behind-the-scenes function that does not often appear on the front stage of the device . However, once a device malfunctions in the market, if these functions do not operate stably, it will not be possible to deal with the malfunction. In other words, remote maintenance features are required to be of even higher quality than other features .
Therefore, when testing a maintainability function for troubleshooting, it is important to pay particular attention to whether the function works stably in any situation .