Microsoft Word Hardware Reconfiguration Methodology V final2

System maintenance

1. Reasons for performing system maintenance

There are a variety of valid reasons why system maintenance should be performed regularly (or periodically), regardless of the maintenance type. The following is non-exhaustive list but it does cover many of the various issues that are important to this section. Consider the following:

1. 
   Reduce the time required for future maintenance.
   

2. 
   Decrease the system’s susceptibility to attacks and exploitation through known vulnerabilities and/or bugs.
   

3. 
   Potentially fix unknown vulnerabilities and/or bugs.
   

4. 
   Ensure better hardware support for through newer device drivers and a newer kernel.
   

5. 
   Improved management of both physical and virtual memory.
   

6. 
   Provide increased system stability via newer device drivers, and provide enhanced hardware features and/or capabilities.
   

7. 
   Through newer kernels provide improved system stability and reliability, new feature enhancements, increased security, and improved and increased hardware support.
   

8. 
   Through updates and upgrades, provide newer system features and enhancements.
   

9. 
   Enable a successful operating system hardware reconfiguration or hardware migration.
   

2. When and why to perform system maintenance

Before proceeding with system maintenance, in any of its various forms, it is important to determine why and if various operating system components should or need to be maintained. For example, if only one application or service requires maintenance then it may be more appropriate to manually modify the service/application instead of implementing an update or upgrade that will affect the entire system. Very often deciding on whether or not to carryout a specific course of action will require an impact assessment to determine what will change and whether the changes are justified vis-à-vis the amount of changes to be implemented.

Often times for small tasks manual system maintenance may be the preferable course of action. Certain system components can be easily maintained by manually while others should be done using updates and upgrades. For example, kernel recompilation using newer source code is not a difficult process, however, all too often required kernel features are excluded from the compilation that can potentially cripple the system. As such an update or upgrade may more appropriate as the kernel has already been configured for specific use with the current operating system. On the other hand, simple changes such as downloading and installing the latest office suite should cause no discernable impact on the system as a whole (other than new suite features). However, each case is different and will be dependent on many factors. Three very important factors to consider are: 1) are modifications required; 2) are they justified, and 3) if so through which means.

There are many reasons both in favour and against any particular course of action. It is therefore highly important to consider both the advantages and disadvantages of any specific course of action before proceeding with any system maintenance, even before laboratory testing. Doing otherwise could prove to be a waste of valuable time and resources that could otherwise have been better spent working on and solving other more pressing system administration-related issues.

There are many times when system maintenance should be performed and other times when it should not. The following is non-exhaustive list but does cover many of the various issues that are important to this section. Consider the following:

1. 
   How difficult is the maintenance to implement? If the maintenance fix is complex or excessively long to implement then it should be done using a more automated method such as an update or upgrade.
   

2. 
   What requires changing? If manual installation of the maintenance fix will cause too many potential changes, incompatibilities, or inconsistencies then they should be implemented using an automated method such as an update or upgrade.
   

3. 
   What requires maintenance? Does the operating system in general require maintenance or specific components such as the kernel (and its subsystems) or system services and applications? Updates are often more effective at providing newer kernels and system components as they are already precompiled for the current platform and distribution.
   
4. 
   Is maintenance to be performed against one or more applications and/or libraries? If this is the case then it is often easier to perform manual system maintenance in so long as the source code does not need to be modified in any major way.
   

5. 
   Does the maintenance require source code modification? If too much source code is to be modified then time might be saved by instead implementing an update or upgrade. On the other hand if there is only a small amount of source to modify then possibly manual system maintenance may be the correct choice of action.
   

6. 
   Is the maintenance necessary to fix one or more specific system bugs? System bugs such as library or kernel bugs should generally be fixed using updates or upgrades rather than manually modifying kernel source code in order not to introduce new incompatibilities or inconsistencies. However, this will depend on the type of bugs and their breadth.
   

7. 
   If the bugs are application-related, do they cause usability issues? It is important to consider if it is worth updating or upgrading an application simply to fix a couple of bugs that cause only minor inconveniences. Sometimes newer applications cause more trouble than they are worth (i.e. user retraining). It is therefore important to determine the severity of the bugs before implementing any changes.
   

8. 
   Will performing maintenance provide any new productivity improvements (i.e. improved functionality or performance, or both) in applications and services or will it improve the overall operating system? What type of changes will be made? Are they far reaching or limited in their scope? Answering these questions will help to determine if the changes should be carried out.
   

9. 
   Is maintenance required to fix various security-related concerns? Depending on the security issue at hand, it may not be necessary to correct, as it may only be applicable to unused system services/applications. On the other hand, not fixing highly used services/applications could increase the system’s overall vulnerability.
   

10. 
    Are new vulnerability and/or other security maintenance fixes available? If they can be implemented without excessively changing or affecting the system then they can be implemented using manual system maintenance. If on the other hand the maintenance fixes are complex to implement or make too many changes (known and unknown) to the system then it may be more appropriate to use an automated method such as an update or upgrade.
    

11. 
    Are the security-related maintenance fixes kernel-related? If so, then it is often best to directly apply the fix to the source code and recompile the kernel. This can also apply to binary patches. However, if the level of changes made to the source code is extensive then it may more appropriate to use an automated method such as an update or upgrade. In addition, kernel recompilation and option selection can be complex and can result in a crippled kernel resulting in an unusable system.
    

12. 
    What are the overall advantages and disadvantages of performing system maintenance? If the advantages outweigh the disadvantages then the system should be maintained using
    

the appropriate maintenance type. However, if there are too many disadvantages using one maintenance type then another type should be used in its place.

13. 
    It is important to consider when the last maintenance-related changes were made. If the system is relatively up to date then it may not be necessary or appropriate to make changes to the system for non-critical maintenance fixes. Sometimes making maintenance-related changes may cause far more work than is necessary for the level of maintenance to be provided.
    

14. 
    Are the maintenance changes critical? If so then they should be implemented unless there is a good reason not to (i.e. services and/or applications rendered non-functional). However, if maintenance-related changes are not implemented immediately then when a more appropriate set is available such as update or upgrade and it does not cause excessive adverse affects then it should be implemented.
    

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