Internal modes and states
Actions (from galculator):
Demo of qalculate and galculator
expression evaluation: ~/271/expressions (code should be in pld.cs.luc.edu/courses/271/spr18/demos/expressionsij.zip)
java expr_eval (traced version is expr_exp)
java expr_assign
Notes: pld.cs.luc.edu/courses/271/spr18/mnotes/recursion.html#exprtrees
Demo of command-line expressions
With a calculator interface, things are a little different. Generally, the '(' key clears the display and starts a new subexpression. Operator keys might display the current operator on the screen. The ')' key acts like the '=' key for the current expression, displaying the results so far. galculator takes this approach.
The other alternative is to display the entire expression on the display line. qalculate does this.
Many of these are from medium.com/@likid_geimfari/the-list-of-interesting-open-source-projects-2daaa2153f7c.
github.com/dosyago/BrowserBox,
dosyago.com
This is a kind of remote browser. It might not display the full rendered content of the page, but you can use it to make remote browser GET/POST requests, and get the results. Results by default are downloaded to the remote server, but it is straightforward to fetch them from there; security-scanning is recommended. (Note the "WTF is this?" section, which was added a week or so after the project first went up (the readme continues to expand rapidly).)
The monetizing-open-source model here mostly seems to be that the open version is a trial version. It's not time-limited, but nor is it quite open-core.
Things to look at:
What do you think of that license?
The argument here is that these are just various "source-available" licenses. They do state outright that "Polyform is not ... Open source or free software."
Licenses to look at:
They give a list of related licenses:
commonsclause.com: an add-on license (to any "permissive" open-source license) that restricts sale, but still allows forking.
Elastic license (www.elastic.co/licensing/elastic-license): note the "Copyright" and "Limitations" sections. You do get to fork the original project, subject to the Limitations, which here are relatively substantial. Can you rewrite the portions of code covered by the license key, so the functionality is available without a license? Looks that way to me, though that might be a big project.
Confluent license (docs.confluent.io/platform/current/installation/license.html): Note the Developer (no time limit, but "single-broker") and Trial (30-day) licenses. No copyright rights are extended by the license.
Some open-source projects and how they communicate
A python plotting library
Has CODE_OF_CONDUCT.md. Also migration-guide.py, for users
Monetization: https://plotly.com/consulting-and-oem/
Lower down, there is a "contributing to plotly" link and a "Community forum" link.
Most recent update is 5 years ago; most are 9+ years ago
Project Abandoned
An astrophysics library for Python
Has a contributions page at www.astropy.org/contribute.html
At www.astropy.org/team.html there is quite a discussion about the project organization. There is a very long list of contributors, and a list of around ~45 voting members.
Don't delete it! Even if your antivirus tells you to. See daniel.haxx.se/blog/2023/04/24/deleting-system32curl-exe.
www.infoworld.com/article/3694090/amazon-s-quiet-open-source-revolution.html.
At least they are no longer fighting open source so strongly.
As told by Lars Wirzenius, classmate of Linus.
Usenet played a role.
lwn.net/SubscriberLink/928581/841b747332791ac4
How did they manage to make so much money selling Linux? IBM bought the company for $34 billion in 2018.
See opencoreventures.com/blog/2023-04-red-hat-model-only-worked-red-hat.
Red Hat started when Linux was novel (March 1993; Linux didn't start until August 1991), and RH offered support. They supported all the weird "system-administration" stuff. At this point, that's easily found online and is often automated.
The OpenCoreVentures argument is that selling support collects pennies per dollar of added value (their term: "low rake"). VCs are not interested in that kind of business model.
In any event, it seems clear nobody today is going to be able to start selling Linux.
Start with af_inet.c::tcp_protocol() and tcp_ipv4.c::tcp_v4_rcv
=> __inet_lookup_skb => __inet_lookup()
=> tcp_v4_do_rcv
=>
tcp_rcv_established() | tcp_v4_hnd_req(sk, skb) | tcp_child_process
=>
tcp_input.c::tcp_rcv_state_process()
->
icsk->icsk_af_ops->conn_request(sk, skb)
==
tcp_v4_conn_request() // see
table at tcp_ipv4.c::line 1758
tcp_v4_hnd_req():
inet_csk_search_req: this is looking for the "request
socket", a mini-socket with additional info
tcp_check_req: checks if there is space in the accept
queue
inet_lookup_established: we *did* just call this: same
as __inet_lookup_established with hnum=dport
main path: ends up returning sk
Caller is tcp_v4_do_rcv();
caller falls through to tcp_rcv_state_process
->
icsk->icsk_af_ops->conn_request(sk, skb)
==
tcp_v4_conn_request() // see table at
tcp_ipv4.c::line 1758
tcp_v4_conn_request(): // handles
incoming SYN
// error cases first
tcp_clear_options();
tcp_parse_options;
tcp_openreq_init
save saddr/daddr in ireq, which is a cast of req, which
is a struct request_sock.
saves req using inet_csk_reqsk_queue_hash_add(sk, req,
TCP_TIMEOUT_INIT); // csk = Connected SocKet
see also inet_csk_search_req
calls __tcp_v4_send_synack
tcp_input.c:
int tcp_rcv_state_process(struct sock *sk, struct
sk_buff *skb) // called by tcp_v4_do_rcv for states
besides ESTABLISHED, LISTEN
ESTABLISHED: tcp_data_queue()
htb_classify()
htb_dequeue()
jiffies
htb_dequeue_tree()