The various components of the user interface are explained here:

Version 15 of the UI features The Edge, which has been replaced by the Favorites (left-navigation) tab in version 16 of the UI, as shown in the following screenshot:

The System Settings modal window is accessible (in UI16) by clicking on the settings gear icon in the Banner Frame. When you are logged in as System Administrator or a delegated developer, you will have the following settings available:

After enabling Show Application and the Update Set picker in the header settings, both drop-down fields will appear in the banner frame, which will enable us to quickly change the active Application scope and Update Set:

The ServiceNow platform comes with a default Application scope named Global and a default Update Set under the global application scope named Default [Global]. We will be covering how the Application scope and the Update Set works in detail later in the book. One key thing to remember is that the Application scope is different to application menu links, which are visible in the left navigator and explained here:

The Application Navigator on the left of the user interface lists all applications menu and modules. An application menu is a set of related modules grouped together as a section, which can be expanded on click, and is denoted by an application label. Once expanded, it lists all modules (navigation links) available under it.

One of the most important aspects of the ServiceNow Application is that it can comprise of one or more modules of different types. Modules types are also referred to as navigation link types.

The administrator can easily customize the order and label of all Applications and Modules, as shown in the following screenshot:

Even though we will be covering Modules in upcoming chapters, to completely understand different types of user interfaces available, we must go through some key types of modules available in ServiceNow.

In the preceding image, Self-Service, Guided Setup, Service Desk, Incident, Problem, and Change (marked in red) are all Application menus. The Incident application menu section is expanded and navigation links under it, including Create New, Assigned to me, Open, Open - Unassigned, Resolved, All, Overview, and Critical Incidents Map (marked in green), are visible and these navigation links are called Modules.

Lists of record modules usually have a New button in the upper-left, which allows you to insert a new record into the table list of records that the module is fetching its data from. Moreover, you will also find a filter icon, which can be clicked to open a query builder known as the Filter UI, as shown in the following screenshot:

The list of records also features a quick search feature at the top section but unlike Filter UI, it can be perform a search only on one of the visible columns:

It also features a simple to use pagination UI in the upper- and lower-right, which allows you to quickly jump through records from one page to another:

Apart from the Filter UI, quick search, and pagination UIs, the list of records module also features UI actions such as list choice and context menu, which are visible when we right-click on the list's column header. It also provides an efficient way to change the sorting order of the list, simply by clicking on the column name on the list's header.

Clicking on the gear icon at the upper-left of the list header brings up the Personalize List Columns modal window, allowing logged-in users to customize columns available to them in the list's grid. You can bring in the columns you want visible to the Selected list from the Available list of columns and click on the OK button to confirm your changes, as shown in the following screenshot:

ServiceNow offers many different form UI elements , such as choice (drop-down), simple text, numeric, price, date, reference field, journal field, and so on, which can be used in forms and catalog pages. Different form UI types can be used to create one form. For example, the New record form of the Incident application, as shown in the following screenshot, can comprise text fields, reference fields, form buttons, header context menus, drop downs, form sections, list fields, and journal fields. Some of these fields can be marked as mandatory:

Some sections of the form are accessible via a tabbed interface as shown here:

We will be covering how to create different form fields and customize form layout in later chapters.

Related lists are one of the most important UI elements available in form pages. A related list can be used to show lists of related records from either, the same or a different table. While we will be covering related lists in detail in later chapters, let us quickly understand how the related list UI works and how it can help augment the information available in any form:

Dot-walking is a concept within ServiceNow that enables you to drill down to records, as in the Filter UI. When you are in the List of Records modules page, you usually end up using the Filter UI. The Filter UI lists all columns in the table. Like the Incident table, it lists Number, short description, created date, caller, and so on. Suppose we want to list all incidents by a Caller named Joe Employee. Using the Filter UI, it is quite easy to do this - simply select the Caller field as one of the filters and set the search value as Joe Employee:

But what if we want to list records based on Callers who are from the sales department? We do not have a department field in the Incident table but we do have such a field in the user table. As we have learnt before in this chapter, the Caller field is of type reference and it is referring to a record in the users table. So, in order to list all Incidents of Callers who are from sales, we will employ a feature available in all Filter UIs called dot-walking:

ServiceNow applications utilize system resources that are shared by all applications. These include user interface, security access control, workflow engines, reporting, and notification handlers along with system resources such as database, storage, and memory.

Each ServiceNow instance has its own database and is used to store data in tables comprised of various columns. While each application has their specific set of tables and columns, there are some tables like users, cmdb_ci, and tasks shared by many different applications. All records stored in tables are structured quite similarly with the column sys_id as the unique primary key thus enabling a single system of records that correlates all business services and processes throughout the enterprise.

While working on the ServiceNow platform, developers do not have to worry about how the database is set up or how tables are structured. On the other hand, administrators have access to many data management tools, giving them enough control over tables and data stored in them Chapter 3, Data Management.

One of the most important contributing factors to the success of ServiceNow and reasons why enterprises trust it, is their Advanced High Availability (AHA) architecture. It is one of the key elements of ServiceNow; being able to offer a true enterprise cloud. Their multi-instance architecture along with Advanced High Availability is designed exclusively by ServiceNow to meet and exceed their enterprise customer's stringent requirements surrounding data security, availability, and performance.

ServiceNow's datacenters are designed to be available 24/7, 365 days a year and all data center components like servers and network devices are redundant and have multiple network paths to avoid a single point of failure. They back customer's production instances with multiple connections to the internet and load balance them within each data center. Furthermore, database servers in one data center are asynchronously replicated in real time to a peer data center within the same geographic region:

As of writing this book, ServiceNow operates a total of 16 data centers (eight pairs) in the following geographic locations:

Furthermore, to ensure data is never lost, ServiceNow conducts regular backups. The backup cycle consists of four weekly full backups and the past 6 days of daily, differential backups that provide 28 days of backups. ServiceNow doesn't rely on tapes and stores backup data to disk. Also, no backups are sent off site.