*
     * @param cfg the configuration containing machine ID
     */
    public AvSingleHost(final Configuration cfg) {
        this(new byte[8], cfg.getMachineId());
    }

    /**
     * Constructs an AvSingleHost with custom data and machine ID
     *
     * @param customData custom data for the single host (8 bytes)
     * @param machineId the machine identifier (32 bytes)
     */

## Server Machine and Server Program { #server-machine-and-server-program }

There's a small detail about names to keep in mind. 💡

The word "**server**" is commonly used to refer to both the remote/cloud computer (the physical or virtual machine) and also the program that is running on that machine (e.g. Uvicorn).

        assertArrayEquals(rawData, avSingleHost.getRaw());
    }

    /**
     * Test constructor AvSingleHost(Configuration cfg).
     * Should use the machine ID from the configuration.
     */
    @Test
    void testAvSingleHostConfigurationConstructor() {
        Configuration mockConfig = mock(Configuration.class);
        byte[] expectedMachineId = new byte[32];

## Use Case { #use-case }

Let's start with an example **use case** and then see how to solve it with this.

Let's imagine that you have some **machine learning models** that you want to use to handle requests. 🤖

* **Machine Learning**: Normalmente exige muita multiplicação de matrizes e vetores. Pense numa grande planilha com números e em multiplicar todos eles juntos e ao mesmo tempo.

### Concurrency + Parallelism: Web + Machine Learning { #concurrency-parallelism-web-machine-learning }

With **FastAPI** you can take advantage of concurrency that is very common for web development (the same main attraction of NodeJS).

But you can also exploit the benefits of parallelism and multiprocessing (having multiple processes running in parallel) for **CPU bound** workloads like those in Machine Learning systems.

## What Does Deployment Mean { #what-does-deployment-mean }

To **deploy** an application means to perform the necessary steps to make it **available to the users**.

For a **web API**, it normally involves putting it in a **remote machine**, with a **server program** that provides good performance, stability, etc, so that your **users** can **access** the application efficiently and without interruptions or problems.

### Server Memory { #server-memory }

For example, if your code loads a Machine Learning model with **1 GB in size**, when you run one process with your API, it will consume at least 1 GB of RAM. And if you start **4 processes** (4 workers), each will consume 1 GB of RAM. So in total, your API will consume **4 GB of RAM**.

And if your remote server or virtual machine only has 3 GB of RAM, trying to load more than 4 GB of RAM will cause problems. 🚨

 * Windows command prompt you can see
 * what names a host registers with the nbtstat command.
 *
 *  * <blockquote>
 *
 * <pre>
 * C:\&gt;nbtstat -a 192.168.1.15
 *
 *        NetBIOS Remote Machine Name Table
 *
 *    Name               Type         Status
 * ---------------------------------------------
 * JMORRIS2        &lt;00&gt;  UNIQUE      Registered
 * BILLING-NY      &lt;00&gt;  GROUP       Registered

## `fastapi run` { #fastapi-run }

Executing `fastapi run` starts FastAPI in production mode by default.