RB to SIX Converter

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Ebook to Terminal Art

Transform RB ebook pages into SIX SIXEL graphics — viewable directly inside terminal emulators that support the protocol.

Runs on Our Servers

All conversion processing happens in the Convertio cloud. Your machine handles zero computation during the RB to SIX conversion.

Beautifully Simple

Upload, choose SIX, download. No registration, no desktop software, no command-line tools — just a web browser.

How to convert RB to SIX

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose six or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your six file right afterwards

About formats

RB is the native ebook format of the Rocket eBook, one of the first commercially available dedicated e-reading devices, developed by NuvoMedia and released in October 1998. Founded by Martin Eberhard and Marc Tarpenning — who later co-founded Tesla Motors — NuvoMedia designed the Rocket eBook as a handheld device with a reflective LCD screen, capable of storing approximately ten books in its internal memory. The RB format packages HTML-based content along with embedded images, metadata, and a table of contents into a single binary container optimized for the device's limited hardware. Content was purchased and downloaded through NuvoMedia's RocketLibrarian desktop software. A notable advantage of the format was its early support for bookmarking, annotation, dictionary lookups, and adjustable font sizing — features now standard on modern e-readers but revolutionary in the late 1990s. The Rocket eBook demonstrated viable commercial demand for dedicated reading devices, paving the way for subsequent platforms from Sony, Amazon, and others. NuvoMedia was acquired by Gemstar-TV Guide International in 2000, which discontinued the device line in 2003. While RB files are largely a historical curiosity today, they can be converted to modern formats using ebook management tools, and the format remains significant as a pioneering chapter in the evolution of digital reading.
Developer: NuvoMedia
Initial release: 1998
SIX is a file extension for SIXEL (Six Pixel) graphics data, a bitmap graphics format developed by Digital Equipment Corporation (DEC) in 1983 and introduced with the LA50 dot matrix printer. SIXEL encodes images as a sequence of printable ASCII characters, where each character represents a column of six vertical pixels (a 'sixel') — the character's ASCII value minus 63 provides a 6-bit binary pattern, with each bit controlling one pixel in the vertical column. The encoding is structured as a series of sixel bands (each six pixels tall) across the image width, with control sequences for color selection (up to 256 registers with HLS or RGB specification), repeat counts (run-length encoding for efficiency), carriage return, and newline commands. SIXEL data is transmitted to the output device using DEC's standard escape sequence protocol, embedded within the text stream alongside regular character output. Originally designed for DEC's line of printers and later supported by DEC VT-series terminals (VT240, VT330, VT340), SIXEL has experienced a remarkable revival in modern terminal emulator software. One advantage is terminal-native image display: SIXEL allows images to be rendered directly within a text terminal session without requiring a graphical window system, enabling command-line tools to display graphs, photographs, and previews inline with text output. This capability has driven adoption in modern terminals like mlterm, xterm, WezTerm, and foot. SIX/SIXEL data can be generated by ImageMagick, libsixel, and chafa, and viewed in any SIXEL-capable terminal emulator.
Initial release: 1983

Frequently Asked Questions

Why convert RB to SIX?

RB is a defunct 1998 ebook format. SIX (SIXEL) conversion lets you display ebook page images directly inside compatible terminal emulators.

What displays SIX files?

Terminal emulators like mlterm, xterm (with SIXEL support), MinTTY, and DEC VT terminals can render SIX graphics inline.

What is SIXEL graphics?

SIXEL is a bitmap graphics protocol from DEC that embeds images as character sequences within terminal data streams.

Is there any cost?

None — RB to SIX conversion on Convertio is free. Premium plans unlock batch operations and expanded file capacities.

How secure is the process?

Convertio deletes your RB uploads after processing and removes SIX output files from its servers within 24 hours.