Not a new OS. The same one, rebuilt.¶
There is already excellent replacement firmware for the iPod classic. Rockbox runs on it and has for years, and it is good software. What it is not is the iPod -- the interface, the feel of the wheel, the way a list moves under your thumb, the transitions Apple spent years tuning. Those things live in the retail firmware and nowhere else, and they are why the object is still worth carrying.
So Chikuma does the harder thing: it reproduces RetailOS itself, function by function, from the shipped image -- with the original firmware kept alongside as the thing every answer is checked against.
The oracle is the firmware¶
A difference between Chikuma and RetailOS means Chikuma strayed, not that the device is odd. Both boot the same disk on the same emulated machine, so "is this right" is a screenshot subtraction rather than an opinion.
Nothing invented, nothing unlabelled¶
Every value is MEASURED (read from the image or a live trace), INFERRED (reasoned on top of a measurement), or OURS (a stand-in that says so, in the file, at the place it stands in).
The UI builds itself¶
Screens are not hand-drawn here any more than they are there: the archive's records name the classes, the rows, the events and the destinations, and the code walks them.
Real libraries, not re-typed ones¶
Apple shipped FreeType, SQLite, zlib and the Vincent OpenGL ES implementation inside this firmware. Chikuma takes them from upstream at the version the image shows, and recovers only the parts Apple grew onto them.
Where it is today¶
It boots. The kernel is the firmware's own RTXC design with its real task table. The disk, the filesystems, the display pipe, the wheel and the PMU are driven. The menus build from the archive and drill down through Artists, Albums and Songs. Music plays through the device's hardware decoder, and video decodes clean.
Not a release
There is no installable build. The hardware install path exists and has been exercised, but it is developer plumbing, not a product -- read On the device before going anywhere near a real iPod.
Why "Chikuma"¶
千 sen is a thousand. 曲 kyoku is a musical track. Together, a thousand songs -- the five words Steve Jobs used to introduce the iPod in 2001. Read as one word, 千曲 is Chikuma: a river in Nagano, named for the thousand bends the water takes on its way down from the mountains. It takes a long, winding path to get where it is going, and it is still running.
No pod suffix, no Apple-derived morpheme, no trademark surface. Chikuma is not affiliated with,
endorsed by, or connected to Apple Inc.