| Roll Number | 00677611 |
| ----------- | -------- |
| ID          | CHC119   |

# 1 - Linux Bash

### 1.1 - If Statements

![](Pasted%20image%2020240421152012.png)
![](Pasted%20image%2020240421151943.png)

### 1.2 - Processing Variable Number of Arguments with While, Using if

![](Pasted%20image%2020240421161729.png)
![](Pasted%20image%2020240421161749.png)

# 2 - Linux System Administration

#### Setup:

- Create **sysadmin** user:
  ![](Pasted%20image%2020240421162622.png)
- Add **sysadmin** to the **root** group
  ![](Pasted%20image%2020240421162657.png)
- Create global_aliases.sh and set permissions
  ![](Pasted%20image%2020240421170953.png)
- Create aliases:
  ![](Pasted%20image%2020240421171121.png)
- Add source for existing users:
  ![](Pasted%20image%2020240421171300.png)
- Create users:
  ![](Pasted%20image%2020240421163023.png)
  ![](Pasted%20image%2020240421163115.png)
  ![](Pasted%20image%2020240421163226.png)
- Create group for Hugh and Ryan
  ![](Pasted%20image%2020240421163525.png)
- Add Hugh and Ryan to the group
  ![](Pasted%20image%2020240421163651.png)
- Create shared directory
  ![](Pasted%20image%2020240421163552.png)
- Set permissions to directory to allow root and sharedaccess to read, write and execute, others can read
  ![](Pasted%20image%2020240421164145.png)
  ![](Pasted%20image%2020240421164122.png)
  ![](Pasted%20image%2020240421163852.png)
- Set permissions of all folders in /home/ to rwx for exclusively the user that owns it. Other users may not read, write or execute
   ![](Pasted%20image%2020240421164526.png)
   ![](Pasted%20image%2020240421164507.png)

#### Testing:

##### Aliases

- Test **ll** alias:
  ![](Pasted%20image%2020240421162846.png)
- Test **la** alias:
  ![](Pasted%20image%2020240421162908.png)
- Test other uses can use alias:
  ![](Pasted%20image%2020240421171351.png)

##### Shared Directory:

- Both Ryan and Hugh can read and write inside the shared directory.
  ![](Pasted%20image%2020240421164724.png)

- Rob can read from the directory:
  ![](Pasted%20image%2020240421170326.png)

- Rob cannot write to the directory:
  ![](Pasted%20image%2020240421165326.png)

##### Home Directories:

- Users cannot access each other's home directories.
  ![](Pasted%20image%2020240421164909.png)
  ![](Pasted%20image%2020240421165151.png)
  ![](Pasted%20image%2020240421165256.png)

- However, the owner may access the home directory.
  ![](Pasted%20image%2020240421165222.png)
  ![](Pasted%20image%2020240421164948.png)

#### bash_history

# CSI Task 1

### a)

![](Pasted%20image%2020240421172016.png)

#### i)

```
X = (A ∧ B ∧ C) ∨ ( ¬A ∧ B ∧ ¬C) ∨ ( ¬A ∧ ¬B ∧ C)
```

#### ii)

```csvtable
source: 1a.csv
```

### b)

Truth Table:

```csvtable
source: 1b.csv
```

Karnaugh Graph:

|     |     | AB  |     |     |     |
| --- | --- | --- | --- | --- | --- |
|     |     | 00  | 01  | 11  | 10  |
| C   | 0   | 1   | 0   | 1   | 0   |
|     | 1   | 1   | 0   | 1   | 0   |

As we can see from the Karnaugh Graph, the output of C is completely irrelevant.

Boolean Expression:

```
OUT = (IN1 ∧ IN2) ∨ ( ¬IN1 ∧ ¬IN2)
```

Logic Circuit:

![](Pasted%20image%2020240421190116.png)

# CSI Task 2

### a)

| Name    | George                                                                                   |
| ------- | ---------------------------------------------------------------------------------------- |
| Decimal | 71,101,111,114,103,101                                                                   |
| Binary  | 1000111,1100101,1101111,1110010,1100111,1100101                                          |
| 8N2     | 0(Idle) 1(Start) 01000111 00(Stop) 1(Start) 01100101 00(Stop) 1(Start) 01101111 00(Stop) |
|         | 1(Start) 01110010 00(Stop) 1(Start) 01100111 00(Stop) 1(Start) 01100101 00(Stop) 0(Idle) |

- ![](Pasted%20image%2020240421194501.png)

### b)

| Sent     | UTF-8 | Binary       | UTF-8 | Received |
| -------- | ----- | ------------ | ----- | -------- |
| G        | 71    | 0100 0111    | 71    | G        |
| e        | 101   | 0110 0101    | 101   | e        |
| o        | 111   | 0110 1111    | 111   | o        |
| r        | 114   | 0111 0010    | 114   | r        |
| g        | 103   | 0110 0111    | 103   | g        |
| e        | 101   | 0110 0101    | 101   | e        |
| Sum      | 601   | 10 0101 1001 | 601   |          |
| Checksum | 89    |              | 89    |          |

601 $mod$ 256 = 89
or,
10 0101 1001 AND
00 1111 1111
00 0101 1001 = 89

Example:

| Sent     | UTF-8 | Binary        | UTF-8 | Received |
| -------- | ----- | ------------- | ----- | -------- |
| G        | 71    | 0100 0111     | 71    | G        |
| e        | 101   | 011**1** 0101 | 117   | u        |
| o        | 111   | 0110 11**0**1 | 109   | m        |
| r        | 114   | 0111 0010     | 114   | r        |
| g        | 103   | 01**0**0 0111 | 71    | G        |
| e        | 101   | 0110 0101     | 101   | e        |
| Sum      | 601   | 10 0100 0111  | 583   |          |
| Checksum | 89    |               | 71    |          |

Here we can detect an error in transmission, since the checksum differs on each side of the message. A checksum however cannot detect *where* an error occurs, just the fact that it has.

### c)

$Baud Rate = \frac{Bitrate}{Bits Per Symbol}$

$Bit Rate = 2MBps$
$Bits Per Symbol = 8 data + 1 start + 2 stop = 11 bits$

$Baud Rate = \frac{2MBps}{11b} = 0.1818MHz = 181.8kHz$

$5F = 5 * \frac{Baud Rate}{2}$
$5F = 5 * 90.9kHz = 454.5kHz$

Required Bandwidth: 454.5kHz

# CSI Task 3

### a)

#### Page Accesses

1. 1 2 3 4 5
2. 2 3 4 1 5
3. 3 4 1 2 5

![](Pasted%20image%2020240421224020.png)

Using the clock algorithm, there are 7 page faults total with this sequence of page accesses.

### b)

Since A has a runtime of 4 seconds, it is impossible to allocate 4-7 (4, 5, 6, 7 -> 5 processes) second runtime with no conflicts, so I will allocate 4 in a process of my choice.

$Response Ratio = \frac{Wait Time + Run Time}{Run Time}$

| Process | Runtime | Start Time | Response Ratio |
| ------- | ------- | ---------- | -------------- |
| A       | 4       | 0          | 1              |
| B       | 5       | 1          | 1.2            |
| C       | 6       | 2          | 1.33           |
| D       | 7       | 3          | 1.43           |
| E       | 4       | 4          | 2              |

Process E has the highest Response Ratio, and will be scheduled first.
Then Process D, Process C, B and finally A.

| t (Time) | Complete Process | Start Process |
| -------- | ---------------- | ------------- |
| 0        |                  | A             |
| 4        | A                | E             |
| 8        | E                | D             |
| 15       | D                | C             |
| 21       | C                | B             |
| 26       | B                |               |

Since the only available process at t=0 is A, it must still be performed first, regardless of where it sits in the queue.
E is then available at t=4, when A is completed, allowing the remaining queue to run in descending order of response ratio.