Tuesday, March 17, 2020

Corona Virus Stat

https://www.lifesavvy.com/21038/the-best-coronavirus-dashboards-to-stay-abreast-of-pandemic-news/

https://mikkegoes.com/computer-programming-languages-for-beginners/

https://www.blic.rs/vesti/svet/kineski-zvanicnik-saopstio-ohrabrujuce-vesti-japanski-lek-protiv-gripa-deluje-protiv/g20h8mb

https://www.instructables.com/id/Homework-Writing-Machine/

https://tools.ietf.org/html/rfc793 [TCP]


MORE TIPS from Flavio:


today I have a few new tutorials for you!
But first, I want to tell you again where you can find my 11 free ebooks: get them here! JavaScript, React, Node, Vue, Svelte, Next, C, HTML, CSS and more!
A couple weeks ago I published the C Beginner's Handbook (download it now in PDFePub and Mobi)
I also released a massive update to the JavaScript Beginner's Handbook (PDFePub and Mobi)
Now, some big news: I have officially started working on my new training program. I called it The JavaScript Bootcamp and it will be the most complete JavaScript and Frontend Development online training program everCheck out the syllabus (still not final, I'm refining and working on it every day) and enter your email on the page if you're interested.
I will work on the course material for the next few months, so it's still a long time before it's ready, but I want to get the ball rolling and let you know about the plans for the future.
Let's now jump to the new tutorials!
A few days ago I was moving a folder full of projects, and it was well over 8GB. Turned out 6GB were node_modules folders. Here's how I bulk removed them.
Next, some networking tutorials:



https://tools.ietf.org/html/rfc768

[Docs] [txt|pdf] [Tracker]

INTERNET STANDARD

RFC 768                                                        J. Postel
                                                                     ISI
                                                          28 August 1980



                         

User Datagram Protocol

----------------------

Introduction ------------ This User Datagram Protocol (UDP) is defined to make available a datagram mode of packet-switched computer communication in the environment of an interconnected set of computer networks. This protocol assumes that the Internet Protocol (IP) [1] is used as the underlying protocol. This protocol provides a procedure for application programs to send messages to other programs with a minimum of protocol mechanism. The protocol is transaction oriented, and delivery and duplicate protection are not guaranteed. Applications requiring ordered reliable delivery of streams of data should use the Transmission Control Protocol (TCP) [2]. Format ------ 0 7 8 15 16 23 24 31 +--------+--------+--------+--------+ | Source | Destination | | Port | Port | +--------+--------+--------+--------+ | | | | Length | Checksum | +--------+--------+--------+--------+ | | data octets ... +---------------- ... User Datagram Header Format Fields ------ Source Port is an optional field, when meaningful, it indicates the port of the sending process, and may be assumed to be the port to which a reply should be addressed in the absence of any other information. If not used, a value of zero is inserted. Postel [page 1]


                                                             28 Aug 1980
User Datagram Protocol                                           RFC 768
Fields



Destination  Port has a meaning  within  the  context  of  a  particular
internet destination address.

Length  is the length  in octets  of this user datagram  including  this
header  and the data.   (This  means  the minimum value of the length is
eight.)

Checksum is the 16-bit one's complement of the one's complement sum of a
pseudo header of information from the IP header, the UDP header, and the
data,  padded  with zero octets  at the end (if  necessary)  to  make  a
multiple of two octets.

The pseudo  header  conceptually prefixed to the UDP header contains the
source  address,  the destination  address,  the protocol,  and the  UDP
length.   This information gives protection against misrouted datagrams.
This checksum procedure is the same as is used in TCP.

                  0      7 8     15 16    23 24    31
                 +--------+--------+--------+--------+
                 |          source address           |
                 +--------+--------+--------+--------+
                 |        destination address        |
                 +--------+--------+--------+--------+
                 |  zero  |protocol|   UDP length    |
                 +--------+--------+--------+--------+

If the computed  checksum  is zero,  it is transmitted  as all ones (the
equivalent  in one's complement  arithmetic).   An all zero  transmitted
checksum  value means that the transmitter  generated  no checksum  (for
debugging or for higher level protocols that don't care).

User Interface
--------------

A user interface should allow

  the creation of new receive ports,

  receive  operations  on the receive  ports that return the data octets
  and an indication of source port and source address,

  and an operation  that allows  a datagram  to be sent,  specifying the
  data, source and destination ports and addresses to be sent.






[page 2]                                                          Postel


28 Aug 1980

RFC 768 User Datagram Protocol IP Interface IP Interface ------------- The UDP module must be able to determine the source and destination internet addresses and the protocol field from the internet header. One possible UDP/IP interface would return the whole internet datagram including all of the internet header in response to a receive operation. Such an interface would also allow the UDP to pass a full internet datagram complete with header to the IP to send. The IP would verify certain fields for consistency and compute the internet header checksum. Protocol Application -------------------- The major uses of this protocol is the Internet Name Server [3], and the Trivial File Transfer [4]. Protocol Number --------------- This is protocol 17 (21 octal) when used in the Internet Protocol. Other protocol numbers are listed in [5]. References ---------- [1] Postel, J., "Internet Protocol," RFC 760, USC/Information Sciences Institute, January 1980. [2] Postel, J., "Transmission Control Protocol," RFC 761, USC/Information Sciences Institute, January 1980. [3] Postel, J., "Internet Name Server," USC/Information Sciences Institute, IEN 116, August 1979. [4] Sollins, K., "The TFTP Protocol," Massachusetts Institute of Technology, IEN 133, January 1980. [5] Postel, J., "Assigned Numbers," USC/Information Sciences Institute, RFC 762, January 1980. Postel [page 3]

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