IPC

What is IPC?

Inter-process communication, it allows processes to pass information data/ information between each other.

What are two general classes of IPC?

Shared Memory & Message Passing

What is the idea of shared memory? What are advantages and disadvantages of shared memory?

Shared Memory is the idea of reserving some space on ram for a process to allow other processes to read & write from. It is faster than Message Passing as it only needs to ask OS once to reserve the space but it is less safe than message passing as it is more error prone.

What is the idea of message passing? What are advantages and disadvantages of message passing?

The idea of Message Passing is to ask the OS to pass the information from one process to another. It is slower than Shared Memory since it needs to ask the OS every time it needs to pass information but it is much safer since the OS handles most of the risks and it is easier to program correctly.

Can shared memory kind of IPC communication be used for two processes running on two different computers? Why do you think so?

Shared memory is not used to communicate between 2 computers it. There is no direct way for processes running on different computers to access each other’s memory.          

What is a network?

A bunch of computers connected together for data exchange.

What is an IP address? What does a classic IP address (IPv4) look like?

An IP address is a unique identifier used to identify computers or internet nodes.

Classic IP addresses (IPv4) are typically expressed as four decimal numbers between 0 and 255 separated by a period(e.g., 172.127.1.2).

Why IP address alone isn’t enough for networking communications?

An IP address alone is not enough for networking communications because a device requires a subnet mask. The subnet mask is significant because hosts on the same network may communicate without the need of a router, but hosts on separate networks require the use of a router.

What is a networking port?

A unique ID used to send/receive data to/from other computers in the network

• What are well-known ports? (the answer “first 1024 ports” is worth 0 points) -Explain why they are well known ports 

• HTTP – Port 80 HTTP-web-based plain-text surfing

• HTTPS – 443 HTTPS-web-based encrypted websites in our daily work.

• FTP – 21 File Transfer Protocol (FTP) control connection

• 22 - SSH-SCP  Secure Shell, secure logins, file transfers (scp, sftp), and port forwarding

What is a server (like in “web server” or “email server”)?

A server is a computer/program that waits and “listens” for incoming requests from other computers on a network.

What is a client?

A  client is a computer/program that sends requests to another client or server in order to take action.

What is a communication protocol?

A set of rules two or more computers in a network must follow in order to send and request web pages between each other in a network (ex: https).

What is a URL?

An “english-like” name for an internet resource (i.e. a webpage)

What is DNS?

DNS Server converts URLs to IP addresses.

What is RPC?

Remote Procedure Calls, which are used to invoke procedures or start functions on remote computers or hosts.