Processes and Threads (Quiz)

Question 1
The list of processes waiting for a particular I/O device is called a(n) ____.

1. standby queue
2. device queue
3. ready queue
4. interrupt queue

Solution: device queue

Question 2
A _________________ saves the state of the currently running process and restores the state of the next process to run.

1. save-and-restore
2. state switch
3. context switch
4. process control block

Solution: context switch

Question 3
The ____ of a process contains temporary data such as function parameters, return addresses, and local variables. 

1. text section
2. data section
3. program counter
4. stack 

 Solution: stack

Question 4
A process that has terminated, but whose parent has not yet called wait(), is known as a ________ process. 

1. zombie
2. orphan
3. terminated
4. init 

 Solution: zombie

Question 5
The _______ process is assigned as the parent to orphan processes.

1. zombie
2. init
3. main
4. renderer 

 Solution: init

Question 6
Which of the following statements is true?

1.  Shared memory is typically faster than message passing.
2. Message passing is typically faster than shared memory.
3. Message passing is most useful for exchanging large amounts of data.
4. Shared memory is far more common in operating systems than message passing. 

Solution: Shared memory is typically faster than message passing.

Question 7
A process control block ____.

1. includes information on the process's state
2. stores the address of the next instruction to be processed by a different process
3. determines which process is to be executed next
4. is an example of a process queue 

 Solution: includes information on the process's state

 Question 8
All processes in UNIX first translate to a zombie process upon termination.

1. True
2. False 

 Solution: True

Question 9
Child processes inherit UNIX ordinary pipes from their parent process because:

1.  The pipe is part of the code and children inherit code from their parents.
2. A pipe is treated as a file descriptor and child processes inherit open file descriptors from their parents.
3. The STARTUPINFO structure establishes this sharing.
4. All IPC facilities are shared between the parent and child processes. 

Solution: A pipe is treated as a file descriptor and child processes inherit open file descriptors from their parents.

Question 10
The _____________ refers to the number of processes in memory.

1. process count
2. long-term scheduler
3. degree of multiprogramming
4. CPU scheduler

Solution: degree of multiprogramming

Question 11
_____ is not considered a challenge when designing applications for multicore systems.

1. Deciding which activities can be run in parallel
2. Ensuring there is a sufficient number of cores
3. Determining if data can be separated so that it is accessed on separate cores
4. Identifying data dependencies between tasks.

Solution: Ensuring there is a sufficient number of cores

Question 12
Which of the following would not be an acceptable signal handling scheme for a
multithreaded program?

1. Deliver the signal to the thread to which the signal applies.
2. Deliver the signal to every thread in the process.
3. Deliver the signal to only certain threads in the process.
4. Do not deliver the signal to any of the threads in the process.

Solution: Do not deliver the signal to any of the threads in the process.

Question 13
The ____ multithreading model multiplexes many user-level threads to a smaller or equal number of kernel threads.

1. many-to-one model
2. one-to-one model
3. many-to-many model
4. many-to-some model

Solution: many-to-many model

Question 14
A _____ uses an existing thread — rather than creating a new one — to complete a task.

1. lightweight process
2. thread pool
3. scheduler activation
4. asynchronous procedure call

Solution: thread pool

Question 15
_________ involves distributing tasks across multiple computing cores.

1. Concurrency
2. Task parallelism
3. Data parallelism
4. Parallelism

Solution: Task parallelism

Question 16
A ____ provides an API for creating and managing threads.

1. set of system calls
2. multicore system
3. thread library
4. multithreading model

Solution: thread library

Question 17
Thread-local storage is data that ____.

1. is not associated with any process
2. has been modified by the thread, but not yet updated to the parent process
3. is generated by the thread independent of the thread's process
4. is unique to each thread

Solution: is unique to each thread

Question 18
Signals can be emulated in windows through ____.

1. asynchronous procedure calls
2. local procedure calls
3. remote procedure calls
4. synchronous procedure calls 

 Solution: asynchronous procedure calls

Question 19
Pthreads refers to ____.

1. the POSIX standard.
2. an implementation for thread behavior. 
3. a specification for thread behavior.
4. an API for process creation and synchronization. 

 Solution: a specification for thread behavior.

Question 20
According to Amdahl's Law, what is the speedup gain for an application that is 60% parallel and we run it on a machine with 4 processing cores? 

1. 1.82
2. 0.7
3. 0.55
4. 1.43 

 Solution: 1.43 

Open Source Development Tools and Overview (Quiz)

Question 1
________ is the proper filename for the file that contains targets, dependencies and rules which are used to define how your source code should be built into a binary executable.

1. compiler
2. make
3. gcc
4. Makefile

Solution:  Makefile

Question 2
What editor are you required to use in order to write source code on Linux?

1. nano
2. vim
3. Any editor you are comfortable with
4. emacs

Solution:  Any editor you are comfortable with

Question 3
Which gcc compiler option should you use in order to include symbols for debugging?

1. -Wextra
2. -o
3. -Wall
4. -g  

Solution: -g

Question 4
Before committing changes, what git command is used in order to include updates made to files that already exist in a local git repository? 

1. update
2. pull
3. add
4. push  

Solution: add

Question 5
When working with a remote git repository, what command should be used in order to synchronize changes from the the remote repository into the local repository? 

1. update
2. add
3. push
4. pull  

Solution: pull

Question 6
Which is not another term for kernel mode?

1. system mode
2. operating mode
3. privileged mode 
4. supervisor mode 

Solution: operating mode

Question 7
A(n) ________ is the unit of work in a system

1. timer
2. process
3. operating system
4. mode bit  

Solution: process

Question 8
What statement concerning privileged instructions is considered false?

1. They can be executed in user mode.
2. They are used to manage interrupts.
3. They can be executed in kernel mode.
4. They may cause harm to the system. 

Solution: They can be executed in user mode.

Question 9
A(n) ____ is a custom build of the Linux operating system

1. installation
2. LiveCD
3. distribution
4. VMWare Player

 Solution: distribution

Question 10
The most common secondary storage device is ____.

1. magnetic disk
2. tape drives
3. random access memory
4. solid state disks

 Solution: magnetic disk

Question 11
The two separate modes of operating in a system are

1. user mode and kernel mode
2. supervisor mode and system mode
3. physical mode and logical mode
4. kernel mode and privileged mode  

Solution: user mode and kernel mode

Question 12
Embedded computers typically run ____ operating system

1. a clustered
2. a network
3. the Windows XP
4. a real-time

Solution: a real-time

Question 13
Which of the following operating systems is not open source?

1. PCLinuxOS
2. BSD UNIX
3. Linux
4. Windows 

Solution:  Windows

Question 14
Microkernels use _____ for communication.

1. virtualization
2. message passing
3. shared memory
4. system calls 

Solution: message passing

Question 15
If a program terminates abnormally, a dump of memory may be examined by a ____ to determine the cause of the problem. 

1. module
2. control card
3. debugger
4. shell 

 Solution: debugger

Question 16
_____ allow operating system services to be loaded dynamically.

1. Virtual machines
2. Modules
3. File systems
4. Graphical user interfaces

Solution: Modules

Question 17
_____ provide(s) an interface to the services provided by an operating system.

1. System calls
2. Communication
3. Simulators
4. Shared memory

Solution: System calls

Question 18
A microkernel is a kernel ____.

1. that is compressed before loading in order to reduce its resident memory size
2. that is compiled to produce the smallest size possible when stored to disk
3. containing many components that are optimized to reduce resident memory size
4. that is stripped of all nonessential components 

 Solution: that is stripped of all nonessential components

Question 19
A _____ is an example of a systems program.

1.  text formatter
2. database system
3. command interpreter
4. Web browser 

Solution: command interpreter

Question 20
A boot block ____.

1. typically only knows the location and length of the rest of the bootstrap program
2. is composed of multiple disk blocks
3. typically is sophisticated enough to load the operating system and begin its execution
4. is composed of multiple disk cylinders 

Solution:
typically only knows the location and length of the rest of the bootstrap program

How to setup Wallet for Bitcoins

Coinpot is what is called a mircowallet and could be used through a browser.  You do not have to download any software to begin using it.

If you would like to decide to try this, only follow these steps.

Step 1:  Set Up a Coinpot Account

Make an account on coinpot.co that links to your email. Coinpot will allow you to have 5  different cryptocurrenies: Bitcoin, Bitcoin Income, Litecoin, Dash, and Dogecoin. I have properly used it to have most of these.  Here is how it seems like:

Step 2: Connect to Faucets
Faucets are websites that enable you to collect cryptocurrency free of charge (although you can find advertisements on these sites). You have to be cautious since there are a lot of fraud faucets websites on the market! 

Here are a few the the faucets that I've tried and made sure work. You will only have to login using the same mail as your Coinpot account. Many of these faucets should go straight to your Coinpot whenever you claim your coins. They are able to be claimed every 5-15 minutes.  As you do this you can develop a regular loyalty benefit if you do it everyday.

MoonBitCoin

MoonDash

MoonBit

MoonLiteco

MoonDoge

Step 3: Monitor Your Coinpot
It's enjoyment to view the faucets start to grow up as you claim them.  You can even track the value of the currencies as they go up and down each day. Because I've started I have seen them move way up, way down, and then up again!
 

What are Bitcoin Faucets?

When you are new to the concept of Bitcoins the first question that pops into your mind is that where can I get Bitcoins and possibly for free! So, here the Bitcoin Faucets come to play.

Bitcoin faucets, as the name implies are like dripping sinks (taps)… but in this instance, it is cryptocurrency items rather than water. Just while the dripping water takes time to become right into a droplet before it drips, users have to attend for a specific time before they might obtain the accumulated coins.

What are bitcoin faucets?

Bitcoin faucets (it can be for just about any cryptocurrency) are incentive programs that dispenses benefits in the shape of a small fraction of bitcoin for guests to claim. These benefits are dispensed at specific times of time.

Why bitcoin faucets?

Returns have been in place to attract readers to the faucet's webpage. These faucet web sites frequently include advertisements. Advertisers spend the faucet owner to show these ads on his site. Promotion expenses are calculated on Cost per Thousand impression (CPM) basis. This implies, if the site gets more readers and if each visitor uses additional time on the site, then the site owner gets additional money from shown ads. These rewards attract more readers and they return regularly their rewards. The visitor typically eventually ends up spending additional time on the faucet.

In easy phrases — faucets get more recurring visitors to the site; subsequently, the dog owner additional money from the advertisers.

Faucets play an important position in the bitcoin ecosystem. It encourages more people to understand and follow bitcoin.

Who uses bitcoin faucets?

Using a bitcoin faucet is very simple. After you visit the faucet website, you have to enter your bitcoin wallet handle or the e-mail id associated with your CoinPot wallet and hit enter.  A timer begins checking the total amount of time you spend on the site. After you spend a certain amount of time on the site, you are able to claim your reward by clicking the “Claim Now” or similar button. You will have to demonstrate that you're a human by filling out a Captcha or by sloving a simple mathematical issue, (this prevents any computerized program from claiming rewards at standard intervals).  That's it…! You've claimed your reward. Your reward is likely to be awarded possibly straight away or on a selected regular payout day to your wallet.

Typically, faucet have a minimum time span limit between claims by each visitor, in order to prevent one individual from claiming all the available bitcoin from faucet's wallet. This length varies from five minutes to twenty four hours, based upon the faucet.

Where can I find bitcoin faucets?

You'll find them just by looking for Bitcoin faucet on Google or some other search engine of one's choice. The amount of results you get may surprise you. You may find a huge selection of bitcoin faucet to pick from, go ahead, discover and generate several satoshis while at it. (1 Satoshi = 0.00000001 BTC i.e. hundredth of a millionth BTC)

Here are several bitcoin faucet you should check out:

MoonBitCoin

MoonDash

MoonBit

MoonLiteco

MoonDoge

Conclusion

faucet are the most popular sites to help new customers understand bitcoins while making some bitcoins.

 

XSD DataSets and ignoring foreign keys

Question: I have a pretty standard table set-up in a current application using the .NET XSD DataSet and TableAdapter features. My contracts table consists of some standard contract information, with a column for the primary department. This column is a foreign key to my Departments table, where I store the basic department name, id, notes. This is all setup and functioning in my SQL Server.
When I use the XSD tool, I can drag both tables in at once and it auto detects/creates the foreign key I have between these two tables. This works great when I'm on my main page and am viewing contract data.
However, when I go to my administrative page to modify the department data. I typically do something like this:

Dim dtDepartment As New DepartmentDataTable()
Dim taDepartment As New DepartmentTableAdapter()

taDepartment.Fill(dtDepartment)

However, at this point an exception is thrown saying to the effect that there is a foreign key reference broken here, I'm guessing since I don't have the Contract DataTable filled.
How can I fix this problem? I know I can simply remove the foreign key from the XSD to make things work fine, but having the additional integrity check there and having the XSD schema match the SQL schema in the database is nice.

Solution:  You can try turning Check-constraints off on the DataSet (it's in its properties), or altering the properties of that relationship, and change the key to a simple reference - up to you.

How to export data from SQL Server 2005 to MySQL

Question: I've been banging my head against SQL Server 2005 trying to get a lot of data out. I've been given a database with nearly 300 tables in it and I need to turn this into a MySQL database. My first call was to use bcp but unfortunately it doesn't produce valid CSV - strings aren't encapsulated, so you can't deal with any row that has a string with a comma in it (or whatever you use as a delimiter) and I would still have to hand write all of the create table statements, as obviously CSV doesn't tell you anything about the data types.

What would be better is if there was some tool that could connect to both SQL Server and MySQL, then do a copy. You lose views, stored procedures, trigger, etc, but it isn't hard to copy a table that only uses base types from one DB to another... is it?
Does anybody know of such a tool? I don't mind how many assumptions it makes or what simplifications occur, as long as it supports integer, float, datetime and string. I have to do a lot of pruning, normalising, etc. anyway so I don't care about keeping keys, relationships or anything like that, but I need the initial set of data in fast!

Solution: Using MSSQL Management Studio i've transitioned tables with the MySQL OLE DB. Right click on your database and go to "Tasks->Export Data" from there you can specify a MsSQL OLE DB source, the MySQL OLE DB source and create the column mappings between the two data sources.

You'll most likely want to setup the database and tables in advance on the MySQL destination (the export will want to create the tables automatically, but this often results in failure). You can quickly create the tables in MySQL using the "Tasks->Generate Scripts" by right clicking on the database. Once your creation scripts are generated you'll need to step through and search/replace for keywords and types that exist in MSSQL to MYSQL.
Of course you could also backup the database like normal and find a utility which will restore the MSSQL backup on MYSQL. I'm not sure if one exists however.

How would you access Object properties from within an object method?

Question: What is the "purist" or "correct" way to access an object's properties from within an object method that is not a getter/setter method?
I know that from outside of the object you should use a getter/setter, but from within would you just do:
Java:

String property = this.property;

PHP:

$property = $this->property;

or would you do:
Java:

String property = this.getProperty();

PHP:

$property = $this->getProperty();

I am talking about private or protected variables/properties only. When I learned OO I was taught to use getters/setters for every single property even if it was public (and actually I was told never to make any variable/property public). So, I may be starting off from a false assumption from the get go. It appears that people answering this question are maybe saying that you should have public properties and that those don't need getters and setters, which goes against what I was taught, and what I was talking about, although maybe that needs to be discussed as well. That's probably a good topic for a different question though...

Solution: This has religious war potential, but it seems to me that if you're using a getter/setter, you should use it internally as well - using both will lead to maintenance problems down the road (e.g. somebody adds code to a setter that needs to run every time that property is set, and the property is being set internally w/o that setter being called).