Introduction to Operating System (PDF)

COVER PAGE

Section 1: operating systems
I. examples of services provided by an operating system are;
 Program execution- this service enables the operating system to load contents
or sections of a file into memory for the program to begin execution
 I/o operations- this service enables low-level communication to tapes, disks,
serial line and other devices
 File-system manipulation- enables creation, allocation, deletion and naming of
files
 Communication- enables communication of messages between systems
 Error detection- a global program that handles all types of errors at both
software and hardware levels
How the services provide convenience to users.
 Program execution- Program execution provides convenience to the user
because a user level program could not be trusted to allocate CPU time
properly thus this is done by the program execution OS service.
 I/o operations- this service provides convenience to users because user level
programs cannot be trusted to access only devices that they are supposed to
have access to and only access them when they are unused thus the I/o
operations handles this by converting requests into controller or device
specific commands
 File-system manipulation- this service provides convenience to the user
because user-level programs cannot be trusted to ensure adherence to file
protection methods and to allocate free blocks and deallocate free blocks
during file deletion
 Communication- this service is of convenience to users because passing of
messages between systems requires the messages to be converted into
packets and then sent to the network controller then transmitted across a
communication medium and finally reassembles by the destination system.
User level programs cannot be trusted to coordinate access to the network
devices or in some cases user-level programs might receive wrong packets not
intended for them
 Error detection- this service is of convenience to users because inspection
both at hardware and software level has to be coordinated by the OS to
ensure that all data transfers are not corrupted in transit and all data on
media has to be checked for consistency.

Can some of the OS services be provided by user level programs? YES
Some OS services can be provided by user level programs for example memory management but
its impossible for some services to be provided by user level programs
II. To which extent are the two OS's (Linux/Unix and Windows) essentially the same and
importantly different?
Linux/unix and windows are essentially the same because they provide memory
protection as OS services. They are slightly different in terms of running of computer
programs as processes and how they manage concurrency by use of threads.
III. Discuss multiprocessing systems and explain how multiprocessing increases the
utilisation of resources.
Multiprocessing is the ability of a computer to process more than one task
simultaneously. This enables the operating system to run more than one program
concurrently like listen to music while using a word processing program.
Multiprocessing increases the utilisation of resources by having more than one
process running on different cores concurrently while using the same main memory
and peripherals (Marcraft, 2005).
IV. Concept of batch processing operating system
Batch processing in operating systems is the execution of a series of program jobs
without any user intervention. This concept involves executing a series of programs
each on a batch of inputs in comparison to a single input.
Section 2: OS administration using command line interface (CLI)
1. Create a new subdirectory called MN404-temp in your home directory.
2. Create a new subdirectory called assign1 in MN404-temp.

3. Create a new subdirectory called assign2 in MN404-temp.
4. Display the contents of the directory MN404-temp.
5. Delete the directory assign2.
6. Display content of the directory MN404-temp

7. Change your current working directory to MN404-temp.
8. Create a new subdirectory called assign2 in MN404-temp.
9. Create a new file called MyFile.txt using the touch command and insert two lines into the
file.
i. The first line should be a sentence that tells me your favourite movie.
ii. The second line should be a sentence that tells me your favourite food.

10. Display the contents of the file MyFile.txt to the standard output (screen).
11. Copy the file MyFile.txt to directory assign1 and rename it to t_1.txt.
12. Change your working directory to assign1
13. Make a copy of t_1.txt with the name t_2.txt (in the same directory).

14. Display the contents of the directory assign1.
15. Copy the t_1.txt file to directory assign2.
16. Display the contents of the directory assign2.
Q2: Manipulate files using wildcards. (10 marks)
1. Change your current working directory to MN404-temp. (Stay in this directory for the rest of the
steps in question 2)

2. Create a new directory called assign3 in your working directory.
3. Create 9 new files (in directory assign3) named as follows:
i. Test_1.txt
ii. Test_2.txt
iii. Test_1-1.txt
iv. Test_2-1.txt
v. Test_1-2.txt
vi. Test_2-2.txt
vii. Test_1-1.bak
viii. Test_2-2.bak
ix. File_1.bat

4. Display a listing of all the files in the working directory.
5. Display a listing of all the files ending in txt using one command.

6. Display a listing of all the files ending in t using one command.

7. Copy all the files containing "t_1" to the directory assign3 using one command.
8. Display a listing of the contents of the directory assign3.

9. Create a read-only file in your home directory.
10. How will you find which operating system your system is running on in UNIX

Q 3: Use the man command to first learn the syntax and parameters for the commands du, wc and date,
and then use the commands as follows: (2 marks)
1. Print the newline count, the byte counts and the longest line length for the file MyFile.txt in the
directory MN404-temp.
2. Print the current date using the default format.

Reference
[1]Marcraft, "Multiprocessing Fundamentals for the Server+ Exam", Pearson IT Certification, 2005.
[Online]. Available: http://www.pearsonitcertification.com/articles/article.aspx?p=426771&seqNum=2.
[Accessed: 30- Apr- 2018].