x16-PRos

Running x16-PRos on Real Hardware

x16-PRos is designed for 1.44 MB floppy disks but can also run from a USB flash drive. Follow these steps to set up x16-PRos on real hardware. Use the .IMG image for persistent storage or the .ISO image for a live CD experience without saving changes.

Select the Device

Choose a USB flash drive or floppy disk to write the x16-PRos system image. For USB drives, ensure the drive is formatted as FAT12. The .IMG image supports persistent changes, while the .ISO image is for temporary, live sessions.

Write the Image

Download the x16-PRos system image (.IMG or .ISO) and use a tool like Rufus to burn it to your USB drive. Select your USB drive and the image in Rufus, then click START. Wait for the process to complete before safely ejecting the drive.

Configure BIOS for UEFI Systems

x16-PRos relies on BIOS system calls and does not support UEFI directly. If your computer uses UEFI, enable CSM in the UEFI settings. Enter the UEFI setup by pressing keys like F2 or DELETE during boot (check your motherboard manual for the exact key). Locate and enable CSM support.

UEFI CSM Settings — Change DISABLED to ENABLED for CSM support.

Access the Boot Menu

Restart your computer and enter the boot menu (typically using F8, F11, F12, or ESC). Select the USB drive option labeled "USB" (not "UEFI") to boot PRos.

Boot Menu Selection — Select your USB flash drive from the boot menu.

Boot x16-PRos

Press ENTER to start the boot process, which takes approximately 2-5 seconds. Upon first launch, you'll see the PRos installation screen.

Running x16-PRos on Emulators

Emulators are ideal for developers and testers. PRos supports several emulators, with QEMU being the most straightforward option. Follow these steps to run PRos on QEMU.

Install QEMU

Install qemu-system-x86_64 or qemu-system-i386 using your package manager. For example, on Debian-based systems:


sudo apt install qemu-system-x86
# Or
sudo apt install qemu-system-i386

For Arch Linux with audio support, install the PulseAudio package:


sudo pacman -S qemu-audio-pa

Run x16-PRos in QEMU

Launch x16-PRos using the following command, ensuring you have the x16-PRos.img image file:


qemu-system-x86_64 -audiodev pa,id=snd0 -machine pcspk-audiodev=snd0 -fda x16-PRos.img

This command configures QEMU with audio support and boots the PRos image from a virtual floppy disk.

PRos Terminal Commands

The PRos Terminal is a powerful command-line interface for interacting with the OS, supporting commands for disk operations, program execution, and multimedia tasks.

Basic Commands

Command	Description
`help`	Display categorized command reference with navigation
`info`	Show system information and OS details
`cls`	Clear terminal screen
`ver`	Display PRos terminal version
`exit`	Exit to bootloader

System Information

Command	Description
`cpu`	Display detailed CPU information (family, model, cores, cache)
`date`	Show the current date (DD/MM/YY format)
`time`	Show current time (HH:MM:SS format, with timezone)

File Operations

Command	Syntax	Description
`dir`	`dir`	List files in the current directory with size info
`cat`	`cat <filename>`	Display file contents
`size`	`size <filename>`	Show file size in bytes
`del`	`del <filename>`	Delete a file (kernel.bin protected)
`copy`	`copy <source> <dest>`	Copy file (root directory only)
`ren`	`ren <old> <new>`	Rename file (root directory only)
`touch`	`touch <filename>`	Create an empty file
`write`	`write <file> <text>`	Write text to a file

Text Processing

Command	Syntax	Description
`grep`	`grep <file> <text>`	Search for text in a file with line/column highlighting
`head`	`head <filename>`	Display the first 10 lines of a file
`tail`	`tail <filename>`	Display the last 10 lines of a file

Directory Operations

Command	Syntax	Description
`cd`	`cd <dirname>`	Change directory (use `..` for parent, `/` for root)
`mkdir`	`mkdir <dirname>`	Create a new directory
`deldir`	`deldir <dirname>`	Delete an empty directory
`tree`	`tree`	Display directory structure as a tree

Disk Management

Command	Syntax	Description
`dlist`	`dlist`	List available drives with size and usage
`drive`	`drive <letter>`	Switch to another disk drive

Media & Display

Command	Syntax	Description
`view`	`view <file> [-upscale]`	Display BMP image with optional 2x scaling
`chars`	`chars`	Display ASCII character table
`theme`	`theme <name>`	Change color theme (DEFAULT/GROOVYBOX/UBUNTU)
`font`	`font <name>`	Switch font (DEFAULT/BOLD/THIN/ITALIC)

Power Management

Command	Description
`shut`	Shutdown system via APM
`reboot`	Restart system

API Documentation

x16-PRos provides interrupt-driven APIs for developers. Each function is selected via the AH register. All functions preserve registers via pusha/popa unless output registers are specified. On error, the carry flag (CF) is set.

INT 0x21 Output API

INT 0x22 File System API

INT 0x21 — Output API

Handles screen output in VGA 640×480 16-color mode. All text functions support newline (0x0A) conversion to CR+LF.

Display Functions

AH	Function	Input	Output / Notes
`0x00`	Initialize Output	—	Sets VGA mode `0x12` (640×480, 16 colors)
`0x01`	Print String (White)	`SI` = string ptr	Color `0x0F`
`0x02`	Print String (Green)	`SI` = string ptr	Color `0x0A`
`0x03`	Print String (Cyan)	`SI` = string ptr	Color `0x0B`
`0x04`	Print String (Red)	`SI` = string ptr	Color `0x0C`
`0x05`	Print Newline	—	Outputs CR+LF
`0x06`	Clear Screen	—	Resets video mode without reapplying the theme — raw VGA defaults
`0x07`	Set Text Color	`BL` = color (0x00–0x0F)	Sets global color for function `0x08`
`0x08`	Print String (Custom)	`SI` = string ptr	Uses color set by `0x07`
`0x0C`	Clear Screen with Theme	—	Clears screen and reapplies the current theme from `CONF.DIR/THEME.CFG`

Font Control

AH	AL	Function	Input	Notes
`0x09`	`0x00`	Restore Default Font	—	Restores BIOS ROM font
`0x09`	`0x01`	Load Default Custom Font	—	Loads built-in CP866 font
`0x09`	`0x02`	Load Font from File	`SI` = filename ptr	Loads custom .FNT file from disk

Date & Time

AH	Function	Output
`0x0A`	Get System Time	`CH` = hours (0–23), `CL` = minutes, `DH` = seconds
`0x0B`	Get System Date	`CH` = century, `CL` = year (0–99), `DH` = month (1–12), `DL` = day (1–31)

Both functions read the RTC via BIOS INT 0x1A and apply the timezone offset from CONF.DIR/TIMEZONE.CFG. Day boundaries are handled correctly (e.g. UTC+5 at 23:00 rolls the date forward). Values are returned in binary, not BCD.

VGA 16-Color Palette Reference

0x00 Black

0x01 Dark Blue

0x02 Dark Green

0x03 Dark Cyan

0x04 Dark Red

0x05 Dark Magenta

0x06 Brown

0x07 Light Gray

0x08 Dark Gray

0x09 Blue

0x0A Green

0x0B Cyan

0x0C Red

0x0D Magenta

0x0E Yellow

0x0F White

INT 0x22 — File System API

Manages files on FAT12 disks. Filenames must be in 8.3 format (e.g. FILE.TXT), case-insensitive (auto-uppercased).

Initialization

AH	Function	Input	Output / Notes
`0x00`	Re-Initialize File System	—	Resets floppy controller. `CF` on error.

File Operations

AH	Function	Input	Output / Notes
`0x01`	Get File List	`SI` = buffer for 18-byte entries	`BX` = size low, `CX` = size high (32-bit total), `DX` = file count
`0x02`	Load File	`SI` = filename, `CX` = load address	`BX` = file size. `CF` on error.
`0x03`	Write File	`SI` = filename, `BX` = buffer, `CX` = size	Creates or overwrites file. `CF` on error.
`0x04`	Check if File Exists	`SI` = filename	`CF` clear = exists, set = not found.
`0x05`	Create Empty File	`SI` = filename	`CF` on error (exists or dir full).
`0x06`	Remove File	`SI` = filename	Frees clusters. `CF` on error.
`0x07`	Rename File	`SI` = old name, `BX` = new name	`CF` on error.
`0x08`	Get File Size	`SI` = filename	`BX` = size in bytes. `CF` if not found.
`0x10`	Load Huge File	`SI` = filename, `CX` = load offset, `DX` = load segment	Loads files >32 KB across segments. `CF` on error.
`0x13`	Write Huge File	`SI` = filename, `CX` = source offset, `DX` = source segment, `BX` = size low word, `DI` = size high word	Writes files >64 KB from arbitrary `segment:offset`. Replaces existing file. `CF` on error. v0.9

Directory Operations

AH	Function	Input	Output / Notes
`0x09`	Change Directory	`SI` = dirname	`CF` on error (not found).
`0x0A`	Go to Parent Directory	—	`CF` if already at root.
`0x0B`	Create Directory	`SI` = dirname	`CF` on error.
`0x0C`	Remove Directory	`SI` = dirname	`CF` on error (not empty or not found).
`0x0D`	Check if Directory	`SI` = name	`CF` clear = is directory, set = not.
`0x0E`	Save Current Directory	—	Saves current dir state internally.
`0x0F`	Restore Current Directory	—	Restores previously saved dir state.

Drive Management

AH	Function	Input	Output / Notes
`0x11`	List Drives	—	Prints available drives with size info.
`0x12`	Change Drive	`SI` = drive letter pointer	Switches to another disk. `CF` on error.
`0x14`	Get Current Drive Letter	—	`AL` = current drive letter.

Limitations: Root directory max 224 entries. Standard load (0x02) limited to 64 KiB; use 0x10 (Load Huge File) for larger files across segments, and 0x13 (Write Huge File) to save files larger than 64 KB.

Program Examples

Below are example programs demonstrating the use of PRos APIs, written in NASM for the 16-bit x86 architecture.

Hello, World

Description: A simple program to output a text string to the terminal.


[BITS 16]
[ORG 0x8000]

start:
    mov ah, 0x01        ; API output print white string function
    mov si, hello_msg   ; String to output
    int 0x21            ; Call the API function
    ret                 ; Return to the terminal

hello_msg db 'Hello, PRos!', 10, 13, 0

Print Colored Strings

Description: A program to output the same string in multiple colors using different API functions.


[BITS 16]
[ORG 0x8000]

start:
    mov ah, 0x01        ; API output print white string function
    mov si, hello_msg   ; String to output
    int 0x21            ; Call the API function

    mov ah, 0x02        ; API output print green string function
    mov si, hello_msg
    int 0x21

    mov ah, 0x03        ; API output print cyan string function
    mov si, hello_msg
    int 0x21

    mov ah, 0x04        ; API output print red string function
    mov si, hello_msg
    int 0x21

    ret                 ; Return to the terminal

hello_msg db 'Hello, PRos!', 10, 13, 0

PLE (PRos Large Executable)

PLE is the native executable format introduced in x16-PRos v0.9. It is a hybrid between a flat .BIN and MZ EXE file, designed for programs that outgrew the 64 KB segment limit.

Key features

Multi-segment. A PLE contains an instruction table that tells the loader how to lay out each segment in memory.
Embedded metadata. Every PLE file carries a 32-byte description and a 16-byte author name in the header.
Embedded logo. A 64x64 image (4096 bytes) is shipped inside the executable and shown on a splash screen before the program starts.

Header layout

Offset	Size	Field
`0x00`	4 B	Magic `"PLE\0"`
`0x04`	2 B	Format version (currently `1`)
`0x06`	2 B	Entry segment (relative to base)
`0x08`	2 B	Entry IP
`0x0A`	2 B	Stack segment (relative)
`0x0C`	2 B	Stack SP
`0x0E`	2 B	Segment / instruction count
`0x10`	32 B	Description string (NUL-padded)
`0x30`	16 B	Author string (NUL-padded)
`0x40`	4096 B	Embedded 64×64 logo
`0x1040`	n × 8 B	Load instruction table (segment, file offset, length)

Writing a PLE program

The header layout is wrapped in programs/PLE/ple.inc, a small NASM macro library. A minimal program looks like this:


%include "ple.inc"

PLE_HEADER start, "Just another hello world :)", "PRoX-dev"
PLE_LOGO          "logo/hello.raw"

start:
    push cs
    pop ds

    mov ah, 0x01
    mov si, hello_msg
    int 0x21

    retf

hello_msg db 'Hello, PRos! Live long and prosper!', 10, 13, 0

PLE_END

PLE_HEADER, PLE_LOGO, PLE_CODE, PLE_DATA, PLE_END handle the header, logo embedding, segment table and final patches. Use PLE_DATA to declare a separate data segment when the code+data of a single segment exceed 64 KB.

Building the logo

The repository ships a converter script - scripts/img2pleimg.py that turns any PNG/JPG into required format.


python3 scripts/img2pleimg.py my-logo.png logo/hello.raw

When to pick PLE. Use .BIN for small cli utilities, MZ EXE when you need cross-tool compatibility, and PLE when your program is large, wants an embedded splash, or needs the multi-segment loader. PLE is the recommended format for large x16-PRos programs.

x16-PRos: fast and lightweight

System Lightweight

Rich API

Educational

What is the dev branch?

PRos Terminal

System Requirements

Minimal

Recommended

Maximum

Standard Software Package

Running

Credits

PRoX-dev

Qwez-dev

Han Akbe sponsor

Ilnar Karazbaev sponsor

Saeta

Loxsete

Gabriel

Cuzhima

litvincode

Running x16-PRos on Real Hardware

Running x16-PRos on Emulators

PRos Terminal Commands

Basic Commands

System Information

File Operations

Text Processing

Directory Operations

Disk Management

Media & Display

Power Management

API Documentation

INT 0x21 — Output API

Display Functions

Font Control

Date & Time

INT 0x22 — File System API

Initialization

File Operations

Directory Operations

Drive Management

Program Examples

PLE (PRos Large Executable)

Key features

Header layout

Writing a PLE program

Building the logo

Project News

Download x16-PRos

v0.9 - Latest