N: Device Overview

The N: device is FujiNet’s network device, providing your retro computer with direct access to the internet through a familiar device interface. Just as D: accesses disk drives and P: accesses the printer, N: gives programs the ability to communicate over the network using standard I/O operations.

What Is the N: Device?

The N: device is a virtual CIO (Central Input/Output) device implemented by FujiNet. It allows programs to open network connections, read and write data over the internet, and interact with remote file systems – all using the same I/O calls they would use for local devices like disk drives.

This means that existing programs can be adapted to use network resources with minimal changes, and new programs can leverage network capabilities through a well-understood interface.

Supported Protocols

The N: device supports a variety of network protocols:

How It Works

The N: device acts as a bridge between your retro computer and the internet. Your program issues standard I/O calls to the N: device, FujiNet translates those into the appropriate network protocol operations, and the results are passed back to your program.

flowchart LR
    A["Retro Computer
    (Atari, Apple, etc.)"] -->|"CIO / SIO
    Commands"| B["FujiNet
    N: Device Handler"]
    B -->|"TCP, UDP,
    HTTP, FTP, TNFS"| C["Internet
    Services"]
    C -->|"Response
    Data"| B
    B -->|"Status &
    Data"| A

Data Flow in Detail

1. Your program issues a standard OPEN, READ, WRITE, or CLOSE call to the N: device with a URL-like devicespec.
2. The N: device handler (loaded into memory on your retro computer) translates this into an SIO command and sends it to FujiNet.
3. FujiNet parses the devicespec, determines the protocol, and performs the actual network communication over WiFi.
4. Response data flows back through FujiNet to the N: device handler and into your program’s I/O buffer.

sequenceDiagram
    participant App as Your Program
    participant CIO as CIO Handler (NDEV)
    participant SIO as SIO Bus
    participant FN as FujiNet
    participant Net as Internet Host

    App->>CIO: OPEN #1,4,0,"N:HTTP://example.com/file.txt"
    CIO->>SIO: Network Open ($4E)
    SIO->>FN: Devicespec buffer (256 bytes)
    FN->>Net: HTTP GET /file.txt
    Net-->>FN: Response data
    FN-->>SIO: ACK
    SIO-->>CIO: Success
    CIO-->>App: IOCB ready

    App->>CIO: INPUT #1,A$
    CIO->>SIO: Network Read
    SIO->>FN: Read request
    FN-->>SIO: Data from buffer
    SIO-->>CIO: Data
    CIO-->>App: A$ = data

    App->>CIO: CLOSE #1
    CIO->>SIO: Network Close
    SIO->>FN: Close connection
    FN-->>SIO: ACK

The N: Devicespec

All N: device operations use a URL-like devicespec to identify the network resource:

N[x]:<PROTO>://<PATH>[:PORT]/

Examples

Directory Prefix

The N: device supports a directory prefix (or “current directory”) that is automatically prepended to any devicespec you provide. This saves typing when working with a particular server or directory.

For example, if the prefix is set to HTTP://atari-apps.irata.online/, then opening N:BLACKJACK.BAS automatically resolves to N:HTTP://atari-apps.irata.online/BLACKJACK.BAS.

The prefix can be set with the NCD tool or via XIO call 44 from BASIC.

Loading the N: Device Handler

Before your retro computer can use the N: device, the NDEV handler must be loaded into memory. This handler is included on the fnc-tools disk as NDEV.COM.

To load it automatically at boot, rename it appropriately for your DOS:

Pre-configured DOS disks with the N: device handler are available on the TNFS server at apps.irata.online/Atari_8-Bit/DOS/.

When the handler loads successfully, you will see:

FUJINET READY

Quick Smoke Test

To verify the N: device is working, try loading a BASIC program from the network:

RUN "N:HTTP://FUJINET-TESTING.IRATA.ONLINE/BLACKJACK.BAS"

If everything is working, a Blackjack game will load and run. If you encounter errors, see the table below:

Next Steps

• Supported Protocols – detailed guide to each protocol and its URL format
• Tools and Utilities – NCD, NCOPY, NDEL, and other N: device tools
• BASIC Programming Examples – using the N: device from BASIC