2. Unix

Question 1

T/F Commands are case sensitive

Answer 1

T

Question 2

Describe the flow of information between functioning units of a computer

Answer 2

1. Input accepts info (from user or other machines)
2. info passed to memory then the CPU where information is transformed
3. Processed output is returned to the user

Question 3

What are the two main divisions in memory and the Processing unit?

Answer 3

Memory:

1. primary/main storage: program storage during execution
2. secondary storage

CPU:

1. arithmetic logic unit: location of arithmetic & logic operations
2. Control unit: controls operation order; accesses, interprets and directs instructions

Question 4

What are the 3 parts of the unix operating system?

Answer 4

1. kernel : control
2. shell: interface
3. programs: things executed thru shell, via kernel to logic unit

The OS is the suite of programs that make a computer work

Question 5

What is RAM?

Answer 5

The memory that a computer uses when executing a program

Question 6

What is the Kernel & what does it do?

Answer 6

Is the control hub of the OS

1. allocates time and memory to programs
2. Handles the filestore & communications in response to system calls

Question 7

What is the Shell and what does it do?

Answer 7

Is the interface between the user & kernel

It interprets cmd lines from the user and arranges for their execution. The commands themselves are programs

Question 8

What previous shells does the bash shell combine?

Answer 8

• bourne shell (sh)
• C shell (csh)
• Korn shell (ksh)

Question 9

What are some useful features of the Bash shell

Answer 9

1. TAB completion

2. History of commands

Question 10

T/F Everything in UNIZ is either a file or a process

Answer 10

T

Question 11

What is a process?

Answer 11

an executing program identified by a unique process identifier (PID)

Question 12

What is a file and give examples

Answer 12

Is a collection of data created by users via text editors, running compliers etc.

ex. script, directory, machine readable file

Question 13

Describe the process from standard in to out

Answer 13

standard inputs are passed to the program and executed. The processed data is returned through standard out or standard error is something went wrong

Question 14

What is stream in and out

Answer 14

The process of passing an output as the next input and so on

Question 15

What is ssh?

Answer 15

A cryptographic network protocol for secure data communication, remote cmd-line login & cmd execution, other secure network services between 2 networked computers
A private key is used to encrypt and decrypt

Question 16

What does this cmd do:

$scp file1 mhirst@orca1.bcgsc.ca:/home/mhirst/ [enter]

Answer 16

Copies a local file named file1 onto the server and into /home/mhirst dir

Question 17

mhirst@micb405 /]$ ls [enter]

[mhirst@micb405 /]$ ls -a [enter]

Answer 17

list contents in working dir

-a shows everything including hidden files

Question 18

what does mkdir do?

Answer 18

Makes a directory

Question 19

what does “.” and “..” refer to?

Answer 19

”.” current directory (relative path)

“..” parent of the current dir

Question 20

What does the 10 character string next to a file indicate?

Answer 20

file system security 
1. if a dir or not
2 -4: user permissions
5-7: group permissions
8-10: all other permissions

Question 21

In a file security system was does r, w, x, or - mean?

Answer 21

r: can list files in the dir
w: can delete files in the dir
x: can access files in the fir and read if u have permissions on individual files
- : no permission set