In June I published a road map and claimed the list was plumbing, every line of it. It was. Networking, certificates, session persistence, collaboration state, window geometry: nothing on that list would ever appear on a page, and the whole argument for doing it then was that none of it would be sharing the desk when the page finally arrived.

That list is nearly spent, and what replaces it is a different kind of work:

Everything about a piece except the music itself can now be manipulated from the interface.

That reads like a summary. It's actually a precise statement, and it names a boundary the architecture drew long before this summer. Changes to the things that contain the music – musicians, instruments, staves, layouts, and a piece's own settings – announce themselves structurally the instant they happen, on every connected client. Changes to the music itself defer to the formatting pipeline, which is asynchronous and which doesn't yet exist. One side of that line is now complete, all the way up to the interface. The other is a routing-table entry with no producer and no consumer.

The summer went into the first side. Pieces open and save and close and reopen where you left them. Musicians and instruments are created, numbered, renamed, cloned, reordered and deleted by gesture, with the numbering falling out of the gesture rather than out of a dialog. Layouts assemble into scores and parts. A piece's settings live in a window of its own. A field refuses a value it cannot take, in the field you typed it into, in your own language. Every one of those acts is a single transaction, a single event, a single refetch, a single named step in the Edit menu, and the path is identical whether you are working alone or someone on another continent is working beside you.

The semantic model, in other words, finally has a surface. For two years it existed and could only be reached through tests. It can now be reached with a mouse.

Except for the music. Which is what the rest of the tickets are for:

The anxiety inverts here, which I hadn't quite anticipated.

Invisible work fails by remaining invisible. You solve something genuinely difficult and it vanishes into infrastructure, and the better you have done it the less anyone can see. I have written about that loneliness before.

Visible work fails by being looked at. Every judgement I make about a beam, a slur, a page, will be in front of musicians who have spent their lives reading engraved music and who will know immediately, and without being able to say why, whether it's right.

I'd rather have that problem. It is, after all, the one I set out to have.

Revisiting a corner of the undo machinery this week, I noticed something I'd never thought about. A user may well see the Undo menu item change while the menu is open in front of them: the text rewrites itself as they read it.

​I like that. It says that time in Ooloi carries on rather than waiting to be asked.

My first thought was that only people working together on the same piece would ever see it. Somebody else edits, and the menu keeps you honest about whose action you're about to reverse. Then I remembered the rule the whole interface is built on, which is that Ooloi never freezes and never boxes you in.

Which means it will happen to people working alone. A plugin importing a large Finale score exported as MusicXML works away in the background while you carry on with something else; when it finishes, a great deal has entered the piece, and the undo chain changes accordingly. If the menu is open, you watch it change.

​Saving is the same: a large score writes itself out without the machine going away from you while it does. That's also what makes autosave worth having rather than something you switch off in irritation, since it needn't interrupt you, whatever the size of the piece. So are preferences, application and piece alike, where there's no modal box and no OK button, the change taking effect as you make it and everything displaying it following suit.

Which set me wondering what all this will be like for an engraver who has spent twenty years with programs built the other way.

A modal dialogue box stops your time. While one is up, the rest of the program isn't somewhere you can act: there's the question in front of you and nothing else, and the moment you come back to is the moment you left. Almost everything any of us has ever used is built out of these small suspensions, and a working day becomes a sequence of them with work in the gaps. Not that anybody chose it. It was the only thing on offer, and for the most part it was honest, since nothing was going on behind the dialogue anyway.

What interests me is the question underneath. If a tool can attend to one thing at a time, you learn to bring it one thing at a time, and composing or engraving isn't like that. You defer the expensive operation until the passage is finished, because starting it would cost you the room to work in. So what becomes of those habits when the technology stops requiring them, and time simply doesn't stop?

Spring has finally arrived in Stockholm. I mention it only because there's a quality of north European light returning after winter that genuinely affects how work feels.

The past two weeks have been quiet on the Ooloi front, code-wise. I'm being onboarded into a large AWS project at work, where my decisions will eventually affect roughly five thousand developers, and onboarding at that scale absorbs a great deal of attention. What Ooloi work I've done has been architectural cleanup: the sort of small consolidations you make when the ground is about to be built on. Data field validation refactored to be entirely general, for instance. Not glamorous, but the kind of work that matters once it has disappeared from notice.

Ross also arrived this week. The 1987 third edition, posted from Melbourne in a padded envelope, in pristine condition, and now on the desk where it belongs.

Two weeks ago I wrote that I needed the book and couldn't buy it. The void was listening, as the coda noted. It is one thing to write that, and another to hold the consequences. The book is dense and beautifully exact where it counts. It's also, in places, at odds with itself, which is the honest record of any craft this old. The beaming section alone runs to fifty pages and doesn't entirely agree across them; the accidental positioning sections give horizontal spacings down to fractions of a stave space. Exactly what I'd hoped for. Translating it into data and code will be a pleasure.

What strikes me paging through is how much of the material I already know in some sense. Musicians absorb this kind of thing through a lifetime of reading and writing scores. The interest is not the content as content; it's the formalisation. Ross surfaces principles that intuition alone never quite articulates. He's rigorous about things most musicians never have to put into words, and that's where the real value sits. It's also what makes the book usable as a specification rather than as commentary.

The road ahead, briefly. The Piece Window comes first, multi-user collaboration aware from the start, built on the patterns the Instrument Library established. After that: frontend session persistence so windows reappear where you left them; the Piece Preferences window (also collaboration aware); clock skew compensation for reliable distributed undo and redo; and the full multi-mode client work, with Google-Docs-style permission management for connecting peers. That last item closes a chapter. Once it's done, I won't have to think about multi-user logic again. It'll simply be there.

Then plugins for all JVM languages, a first version of MusicXML import and export, and Skia/Skija with GPU acceleration. The last of those is when SMuFL fonts can finally be drawn on the page.

After which the rendering pipeline proper begins. The first stage draws everything except the music: page numbers, titles, headers, footers, staves, system barlines, braces, brackets, instrument names. Crucially, it's done through the plugin system itself, in Clojure plugins. If you don't like the choices, you can replace them, in whatever JVM language suits. I'm not sure it'll ever be necessary, but it can be done if so desired.

Then the interesting material: noteheads, horizontal spacing, flags, augmentation dots, multi-voice collision resolution, accidental clustering, unisons. Everything that isn't a spanner. The solver gets the supposedly easy work first.

Spanners last: beams, ties, slurs, hairpins, glissandi, lyrics, pedalling, 8vas. Where Magnus's question about hovering secondary beams will finally have somewhere proper to live.

But first: piece windows. Expect GIFs/videos soon!​

We have a new year, and it's time to make plans. Ooloi's architecture is now closed, and the work enters a new phase. What follows is a road map, not a schedule – no dates, no promises – but a logical progression.

These stages are different in nature from what has gone before. Conceptually simpler than the deep semantic work (what the music is, how it's represented and manipulated) or the infrastructure (server/client transports and roundtrips, monitoring, certificates). Everything below is comprehensively architectured and implementation-ready. The thinking is done; what remains is execution.