More on system layer

src/synit-as-system-layer.md

@@ -68,3 +68,20 @@ process up to coordinating activity between machines around the world. A distrib
 could be an excellent foundation for collaborative applications, where privacy concerns come to
 the forefront. In effect, a dataspace can become a richly-structured "VPN", containing
 application-specific shared data and with application- or schema-specific access controls.
+
+## References
+
+[Birgisson et al 2014]: #ref:birgisson14
+[**Birgisson et al 2014**] <span id="ref:birgisson14"> Birgisson, Arnar, Joe Gibbs Politz,
+Úlfar Erlingsson, Ankur Taly, Michael Vrable, and Mark Lentczner. “Macaroons: Cookies with
+Contextual Caveats for Decentralized Authorization in the Cloud.” In Network and Distributed
+System Security Symposium. San Diego, California: Internet Society, 2014.</span>
+
+[Ellison 1999]: #ref:ellison99
+[**Ellison 1999**] <span id="ref:ellison99"> Ellison, Carl. SPKI Requirements. Request for
+Comments 2692. RFC Editor, 1999. <https://doi.org/10.17487/RFC2692>.</span>
+
+[Ylonen et al 1999]: #ref:ylonen99
+[**Ylonen et al 1999**] <span id="ref:ylonen99"> Ylonen, Tatu, Brian Thomas, Butler Lampson,
+Carl Ellison, Ronald L. Rivest, and William S. Frantz. SPKI Certificate Theory. Request for
+Comments 2693. RFC Editor, 1999. <https://doi.org/10.17487/RFC2693>.</span>

src/system-layer.md

@@ -90,9 +90,9 @@ For example, a system layer may:
 among other things. All of these areas are common *across* applications, unique to none of
 them.
 
-To come up with this list, I surveyed a number of existing open systems such as Linux
+To come up with this list, I surveyed[^raw-notes] a number of existing open systems such as
-distributions, desktop environments, and so on, plus (in a limited way) Android and Mac OS,
+Linux distributions, desktop environments, and so on, plus (in a limited way) Android and Mac
-looking for commonalities and differences. That is, the list was developed in a largely
+OS, looking for commonalities and differences. That is, the list was developed in a largely
 informal way. Despite this, I've found it a fruitful starting point for an investigation of the
 properties of system layers in general. I welcome additional perspectives that others might
 bring.
@@ -270,13 +270,13 @@ for the addresses of fine-grained resources (e.g. single objects) within a proce
    distributed garbage-collection[^binder-vs-syndicate] that is extremely widely used in
    Android.
 
-   From a [2009 email from Dianne Hackborne](https://lkml.org/lkml/2009/6/25/3):
+   From a [2009 email from Dianne Hackborne](https://lkml.org/lkml/2009/6/25/3): <q
-   <q>For a rough idea of the scope of the binder's use in Android, here is a list of the basic
+   id="binder-success">For a rough idea of the scope of the binder's use in Android, here is a
-   system services that are implemented on top of it: package manager, telephony manager, app
+   list of the basic system services that are implemented on top of it: package manager,
-   widgets, audio services, search manager, location manager, notification manager,
+   telephony manager, app widgets, audio services, search manager, location manager,
-   accessibility manager, connectivity manager, wifi manager, input method manager, clipboard,
+   notification manager, accessibility manager, connectivity manager, wifi manager, input
-   status bar, window manager, sensor service, alarm manager, content service, activity
+   method manager, clipboard, status bar, window manager, sensor service, alarm manager,
-   manager, power manager, surface compositor.</q>
+   content service, activity manager, power manager, surface compositor.</q>
 
 ## Name-binding, name-resolution, and namespaces
 
@@ -374,39 +374,33 @@ Machine and Google's Android backup support libraries.
 
 ## Synthesis, or, Toward a Complete Vision of a System Layer
 
-Want to make it *easy* integrate portions of a system layer together. The core of the core has
+Looking back at all these features and variations in design and implementation, we might
-to be good IPC and state-management and -introspection.
+imagine some kind of ideal system layer.
 
- - systemd/udev/D-Bus/NetworkManager/dhcpcd/etc., as sketched above
+ - It should be structured around a flexible, high-performance communications substrate with a
- - init/inetd/crond/etc., the traditional Unix system layer
+   coherent, system-wide security model, a story around data privacy, flexible name-to-address
- - daemontools/runit/s6: service supervision software
+   mapping, and reliable failure signalling
- - OpenRC/[s6-rc](https://skarnet.com/projects/service-manager.html):
-   service manager and supervisor used in Alpine
- - Android architecture components
- - Erlang's OTP, the system layer for the Erlang virtual operating system
 
-| Component            | SM | RX | HL | AC | PR | IPC | NS | JQ | UI | CF | RR | BK |
+ - It should offer a service description language and a mechanism for managing services,
-|----------------------|----|----|----|----|----|-----|----|----|----|----|----|----|
+   tracking service demand, and responding with appropriate service supply
-| Linux kernel         | ✓  | ✓  | ✓  | ✓  | ✓  | ✓   | ✓  | ✓  |    |    |    |    |
-| udev                 |    | ✓  |    | ✓  |    |     | ✓  |    |    |    |    |    |
-| D-Bus                | ✓  |    |    | ✓  |    | ✓   | ✓  |    |    |    |    |    |
-| NetworkManager       |    | ✓  | ✓  | ✓  |    |     |    |    |    |    |    |    |
-| dhcpcd               |    |    |    |    |    |     |    |    |    |    |    |    |
-| systemd              | ✓  | ✓  |    |    |    |     | ✓  | ✓  |    |    |    |    |
-| daemontools/runit/s6 | ✓  |    |    |    |    |     |    |    |    |    |    |    |
-| OpenRC               | ✓  |    |    |    |    |     |    |    |    |    |    |    |
-| OTP (Erlang)         | ✓  |    |    |    |    | ✓   | ✓  | ✓  | ✓  |    |    |    |
-| X11                  |    |    |    | ✓  |    | ✓   | ✓  |    | ✓  |    |    |    |
-| Time Machine         |    |    |    |    |    |     |    |    |    |    |    | ✓  |
-| Nextcloud            |    |    |    | ✓  |    | ✓   | ✓  |    | ✓  |    | ✓  |    |
-| Syncthing            |    |    |    | ✓  |    |     | ✓  |    |    |    | ✓  |    |
-| Windows Registry     |    |    |    |    |    |     |    |    |    | ✓  |    |    |
-| GNOME                |    | ✓  | ✓  | ✓  |    |     |    |    | ✓  | ✓  |    |    |
-| Android              | ✓  | ✓  | ✓  | ✓  | ✓  | ✓   | ✓  | ✓  | ✓  | ✓  |    |    |
 
- - ideally, a system layer's security mechanisms would offer a coherent, system-wide approach
+ - It should allow modular addition of components that enrich it with additional high-level
-   to security and privacy. few do so
+   perspectives on the system
 
+ - It should offer utility services such as job-queueing and -scheduling, including
+   calendar-like and time-based scheduling
+
+ - It should offer a user interface
+
+ - It should provide data backup services
+
+ - It could provide data replication services
+
+The most important of these is, in my view, the communications substrate, which dovetails
+inextricably with the state-management and -introspection subsystem. A good design for this
+part of a system will have compounded effects and will make it easy to integrate portions of a
+system layer together. (Witness the [success](#binder-success) of Android's binder, discussed
+[above](#binder)!)
 
 ## References
 
@@ -414,12 +408,6 @@ to be good IPC and state-management and -introspection.
 [**Bass et al 1998**] <span id="ref:bass98"> Bass, Len, Paul Clements, and Rick
 Kazman. Software Architecture in Practice. Addison-Wesley, 1998.</span>
 
-[Birgisson et al 2014]: #ref:birgisson14
-[**Birgisson et al 2014**] <span id="ref:birgisson14"> Birgisson, Arnar, Joe Gibbs Politz,
-Úlfar Erlingsson, Ankur Taly, Michael Vrable, and Mark Lentczner. “Macaroons: Cookies with
-Contextual Caveats for Decentralized Authorization in the Cloud.” In Network and Distributed
-System Security Symposium. San Diego, California: Internet Society, 2014.</span>
-
 [Clements et al 2001]: #ref:clements01
 [**Clements et al 2001**] <span id="ref:clements01"> Clements, Paul, Rick Kazman, and Mark
 Klein. Evaluating Software Architectures: Methods and Case Studies. Addison-Wesley,
@@ -433,20 +421,11 @@ January 28, 2019. <https://lwn.net/Articles/777595/>.</span>
 [**Day 2008**] <span id="ref:day08"> Day, John. Patterns in Network Architecture: A Return to
 Fundamentals. Prentice Hall, 2008.</span>
 
-[Ellison 1999]: #ref:ellison99
-[**Ellison 1999**] <span id="ref:ellison99"> Ellison, Carl. SPKI Requirements. Request for
-Comments 2692. RFC Editor, 1999. <https://doi.org/10.17487/RFC2692>.</span>
-
 [Rice 2019]: #ref:rice19
 [**Rice 2019**] <span id="ref:rice19"> Rice, Benno. “The Tragedy of Systemd.” Conference
 Presentation at linux.conf.au, Christchurch, New Zealand, January 24, 2019.
 <https://www.youtube.com/watch?v=o_AIw9bGogo>.</span>
 
-[Ylonen et al 1999]: #ref:ylonen99
-[**Ylonen et al 1999**] <span id="ref:ylonen99"> Ylonen, Tatu, Brian Thomas, Butler Lampson,
-Carl Ellison, Ronald L. Rivest, and William S. Frantz. SPKI Certificate Theory. Request for
-Comments 2693. RFC Editor, 1999. <https://doi.org/10.17487/RFC2693>.</span>
-
 ---
 
 #### Notes
@@ -466,9 +445,9 @@ Comments 2693. RFC Editor, 1999. <https://doi.org/10.17487/RFC2693>.</span>
     YouTube transcript of the talk, and then cleaned it up.
     (Emphasis mine.)
 
-[^libc-resolver]: The resolver built in to libc plays the major part in this; but things like
+[^raw-notes]: The [raw notes that I
-    dnsmasq play a role too, especially when combined with virtual machines running within a
+    took](https://git.syndicate-lang.org/synit/synit/src/branch/main/notes) during my survey
-    host.
+    and during the Synit design process are available.
 
 [^binder-vs-syndicate]: Looking at binder, I see *strong* similarities with the [Syndicated
     Actor Model](syndicated-actor-model.md) and its [protocol](protocol.md)!