Discussion forum: Note that participation is expected.
- No posts is 5%. One post will not get all that.
- Project 3 is usually where lots of issues come up

Project 3 Notes:
- Readme should describe data. Sample queries?
- Change: User-friendly, most or all fields changeable.
- -999 Displays should be tabular, if possible.
- Scripts will be required in Project 3
  * No scripts, no grade
- Input must be error checked; in particular, selecting records by number
  * Numbering of records should occur with -999
- Show the menu every time
- Doxygen mainpages will be point of emphasis in Project 3.
- Project 3 will be submitted as a zip, tar, etc.

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Sockets
- Clients identify the server target by <IP>:<port>
- Server just claims a port using bind.





Project 3

Mutex ==> mutual exclusion

- Ports are open between our three machines, mcg, cats, & calm, 2000-3000
- VPN use is encouraged for accessing 'our' machines (mcg, cats, & calm)
  * To login, on Putty, load your acad profile, change the acad to the other machines (once for each), change the moniker, save.
     Now you can login directly under VPN.

The server controls:
- bin file
- server log
Because the child servers contend to access these resources, synchronization is required.

The first client on a machine:
- Determines this by looking for the semaphores
  > If none found, it does the setup
- blocks other clients from accessing shared resources until it's done setting up
  > Fact: Semaphores come from the factory set to 0, i.e. a binary semaphore is blocked

The server (and clients) may use threads at your discretion.
- Synchronization must be carried out using the best methods; concurrency is a MUST.

Logging may include only the last number in the IP, for brevity.
- The port must be included.

Log files in this project should be persistent.

Foreground/background kbd commands
- fg brings a process that is either suspended or running in the background to the foreground
  * Multiple processes can be in the background, either running or suspended. In that case:
    > jobs will show the processes, with as number
    > To bring the desired process (numbered X) forward, use fg X

Traditional semaphore commands are P (wait) and  V (signal)
- A wait is a request to access the shared resource
- A signal releases access to the shared resource

Whatever can be done on the client side, should be done on the client side.

struct   sembuf {
			ushort	sem_num;	/* semaphore # */
			short	semop; 	/*semaphore operation*/
			short	sem_flg;	/*operation flags*/
}

P() - semop <-- -1
V() - semop <-- 1