There has long been discussion around the topic of which CI Class is appropriate for laptops and PC’s. These are the CI records that represent the computers individual workers utilize for productivity each day. The arguments on this topic center around two classes; the Computer (cmdb_ci_computer) class, and the Personal Computer (cmdb_ci_pc_hardware) class. At the center of the discussion is a desire by some to define configuration items more accurately in the CMDB by the class in which they are stored. The Server class, which is the parent class for a number of classes of servers is extended from the Computer class and thus provides granularity for infrastructure computing so why not remain consistent and leverage the Personal Computer (PC) class for end-user computing devices in the same manner? After all, the PC class is also extended from the Computer class so it just makes sense this way. Others say, “not so fast.”
Having worked with a significant number of ServiceNow Asset plugin and Hardware Asset Management customers, I’d like to proffer my thoughts for consideration should you be involved in this “discussion” within your organization, or if a consultant is guiding you one way or the other. First, let me cut to the chase; for most customers, I don’t think it is beneficial to use the PC class.
Within the ServiceNow CMDB hierarchy, the Computer class, which is extended from the broader Hardware class, is the parent class for computing devices: servers, desktops, laptops, and handheld units. Extending from the Computer class is the Personal Computer class. Why might it be necessary or maybe beneficial to store records there instead of the base Computer class?
Maybe there are additional attributes available on the cmdb_ci_pc_hardware table that are needed to properly manage CI’s throughout their operational lifecycle? Looking at the CMDB structure alone, there is no benefit to using the PC class over the Computer class as the PC class adds no additional data attributes in which to store operational, characteristic, or identifying data. You can visualize the previous statement in the image below. Note that the Computer table has a “plus” sign followed by the word “columns”. This indicates columns unique to the cmdb_ci_computer table are present and can be viewed by clicking the plus sign. Now, look at the Personal Computer table. It is the fifth table down in the column of tables extending from the Computer table on the left of the image. There is no “plus sign” followed by the word “columns” there, which indicates there are no unique attributes to display. Scratch one reason to prefer the PC class over the Computer class.
Note that the image is also added as an attachment. Downloading it can give you the flexibility to make it larger and easier to read. Clicking the image will also make it larger.
Granular classification is another reason why one might prefer the PC Class over the Computer class. PC Hardware is more granular in that it segments End User Computing devices from the more inclusive Computer table. This reasoning also holds with the Server table extended from the Computer table. Server, in turn, has a number of tables representing different server types extending from it. However, the Handheld Computing Device table is also extended from Computer and is not extended from Personal Computer, which one might expect. There is also the Form Factor attribute on the Computer table to take into account. This baseline choice list, shown below, contains the granularity most CMDB Managers are looking for without a need to utilize the PC class. Present among the available choices are both Desktop and Laptop, which accounts for both computer types generally tracked in the PC Class.
Let’s also talk about Discovery Sources. The Service Graph Connector for Microsoft SCCM, ServiceNow Discovery, and the Agent Client Connector all integrate with the CMDB to store data in the Computer Class. Recently, one of my fellow Rangers, Doug Schulze, did a write-up and video on how to modify ServiceNow Discovery to write to the PC Class instead of the Computer Class. A key takeaway was that once you make that change, you own that change because you have modified baseline ServiceNow features.
In this writer's opinion, it is best to not adopt use of the PC Class over the baseline Computer class. But, I’ll give you this one concession. There are a myriad of business reasons for doing something and your organization may have a very legitimate reason for needing to use the PC Class. That is the beauty of the ServiceNow Platform. Customers can leverage its features to meet all manner of use cases that haven’t been discreetly provided for by baseline product features or configurations. If this is you, go for it! Utilize the Personal Computer class to meet your needs. If this is not you, I recommend, you stick with the Computer class.
