Posts

Further Kallbak Improvements: searchable insertion of questions inside PowerPoint

09/08/2025

Further Kallbak Improvements: searchable insertion of questions inside PowerPoint

I decided to make the UI of the PowerPoint element of Kallbak better, so enabled the facility to see all the questions and be able to search and find a question, then with a single button press, the question is entered into the default template. All you have to do then is style it as your school desires or it meets your own peronal preferences. Even the QR Code is automatically generated for you.

Kallbak is free for educators. I’m using it myself, so why not have a try yourself? Visit www.kallbak.com and register for free.

Coding

Kallbak now features Likert Scale Questions

08/08/202508/08/2025

Kallbak now features Likert Scale Questions

Likert Scales are the 1-5 rating scales used all over the place. They have a long history in research questionnaires and have been seriously over-used by web marketeer, but they are really useful in understanding by how much someone feels.

There is a place for this kind of question in the classroom so I have built in a configurable option for Likert Scales.

You can have as many options on the scale as you like, but it is usually an odd number. Given the size of a mobile screen this means in reality a maximum of 7.

When displayed on the screen, responses arrive in real-time as before much like a multiple choice. If anyone would like a different kind of display for a Likert Scale then please contact me and I will try and implement it.

This is the PowerPoint view

Coding

Kallback Powerpoint Module: Improved Wordcloud

05/08/2025

Kallback Powerpoint Module: Improved Wordcloud

Whereas creating a wordcloud within a web-based App was relatively easy, creating that inside PowerPoint (one of the key features of Kallbak) was quite challenging, and the code inside PowerPoint was not as good as the web-based one.

However, that has been vastly improved with release 1.2 of the CodeMonkey Kallbak add-on for PowerPoint which connects to my own self-written API endpoint and delivers a wordcloud graphic on demand.

The PowerPoint Add-in can be obtained at: https://www.kallbak.com/download once you have registered (for free!) and installed as a PowerPoint Add in.

The WordCloudAPI is written in NodeJS and therefore released under the MIT Licence and can be found on my Github at https://github.com/SimonRundell/WordCloudAPI should you wish to adopt, adapt and improve it or host it on your own webserver. There is also a demonstration of a client there to access it on a web page: https://github.com/SimonRundell/WordCloudAPI

General

Form multiple drives into a single mountable drive on…

03/08/2025

Form multiple drives into a single mountable drive on Ubuntu

This is a script which does the above. I have three additional drives on my Ubuntu box which I wanted to amalgamate into a single mount for my media resources for sharing. I could have done it manually, one drive at a time, but why not spend hours working on a bash script that does it in less than a minute and I could use again (someday) or you might want to be able to use it for your own media server.

#!/bin/bash
set -e

# === CONFIGURATION ===
DISKS=("/dev/sdb" "/dev/sdc" "/dev/sdd")
VG_NAME="mediavg"
LV_NAME="medialv"
MOUNT_POINT="/mnt/media"
FS_TYPE="ext4"

echo "=== STEP 1: Wiping existing data and creating GPT partitions ==="
for disk in "${DISKS[@]}"; do
    echo "Wiping and partitioning $disk"
    sudo wipefs -a "$disk"
    sudo parted -s "$disk" mklabel gpt
    sudo parted -s "$disk" mkpart primary 0% 100%
done

sleep 2  # Let the kernel re-read the partition table

# Identify partitions (assumes each drive has one partition now)
PARTITIONS=("${DISKS[@]/%/1}")

echo "=== STEP 2: Creating LVM Physical Volumes ==="
for part in "${PARTITIONS[@]}"; do
    echo "Creating PV on $part"
    sudo pvcreate --force --yes "$part"
done

echo "=== STEP 3: Creating Volume Group ($VG_NAME) ==="
sudo vgcreate "$VG_NAME" "${PARTITIONS[@]}"

echo "=== STEP 4: Creating Logical Volume ($LV_NAME) ==="
sudo lvcreate -l 100%FREE -n "$LV_NAME" "$VG_NAME"

echo "=== STEP 5: Creating $FS_TYPE filesystem ==="
sudo mkfs.$FS_TYPE "/dev/$VG_NAME/$LV_NAME"

echo "=== STEP 6: Creating and mounting to $MOUNT_POINT ==="
sudo mkdir -p "$MOUNT_POINT"
sudo mount "/dev/$VG_NAME/$LV_NAME" "$MOUNT_POINT"

echo "=== STEP 7: Adding to /etc/fstab for persistence ==="
UUID=$(sudo blkid -s UUID -o value "/dev/$VG_NAME/$LV_NAME")
echo "UUID=$UUID $MOUNT_POINT $FS_TYPE defaults 0 2" | sudo tee -a /etc/fstab

echo "Done: Your media volume is mounted at $MOUNT_POINT"

Copy and paste this to a text file with nano:

nano setup_media_pool.sh

Then make it executable:

chmod +x setup_media_pool.sh

To run it, type:

sudo ./setup_media_pool.sh

…and it will set it upo for you. If you don’t have 3 extra drives, remove sdc and sdd, but you must realise that this operation will delete all the data on these drives so make sure you want to do this as this cannot be gone back on.

Then I configured Samba file sharing with the following smb.conf so that only machines in my local network 192.168.0.* could access it.

[global]
   server string = Media Server
   workgroup = WORKGROUP
   netbios name = MEDIASERV
   server role = standalone server
   map to guest = Bad User
   log file = /var/log/samba/log.%m
   max log size = 1000
   dns proxy = no

   # Restrict access to local network only (optional but recommended)
   interfaces = lo enp0s3 192.168.0.0/24
   bind interfaces only = yes

   # Enable guest access
   security = user
   guest account = nobody
   usershare allow guests = yes

# Disable unused services
   load printers = no
   disable spoolss = yes
   printing = bsd

# Media Share
[MEDIA]
   comment = Shared Media Storage
   path = /mnt/media
   browseable = yes
   writable = yes
   guest ok = yes
   public = yes
   create mask = 0775
   directory mask = 0775
   force user = nobody
   force group = nogroup

Test the configuration first:

sudo testparm
sudo systemctl restart smbd

and then check the permissions of the shared folder:

sudo chown -R nobody:nogroup /mnt/media
sudo chmod -R 775 /mnt/media

I did have to create a Samba user to log in as:

sudo smbpasswd -a smbsharer

…and then set a password, after which you enable it with the following:

sudo smbpasswd -e smbsharer

…and you’re done! From Windows, map a network drive to \\MEDIASHARE\MEDIA and enter the user smbsharer and the password you set, and you are connected.

Computer Science

Teaching the Bubble Sort Algorithm using Pringles

30/07/202530/07/2025

Teaching the Bubble Sort Algorithm using Pringles

Creative Commons Simon Rundell CC NC-BY-SA 2025. Use freely. Or make your own. I just did it on my phone.

General

RIP Tom Lehrer

29/07/202529/07/2025

RIP Tom Lehrer

Aged 97. He gave me so much fun.

Computer Science

Lesson Notes: Network Protocol Layers

29/07/2025

A network layer model helps break down communication into smaller, more manageable functions. The most common model is the OSI (Open Systems Interconnection) Model, which has seven layers, each responsible for a specific role in data transmission.

Application Layer – User-facing services (e.g., web browsing, email).
- Protocols: HTTP, HTTPS, FTP, SMTP, POP3
Presentation Layer – Formats and encrypts data for applications.
- Protocols: SSL/TLS
Session Layer – Manages connections and sessions between devices.
- Protocols: NetBIOS, RPC
Transport Layer – Ensures reliable data delivery (e.g., error checking).
- Protocols: TCP (reliable), UDP (fast but unreliable)
Network Layer – Routes data between networks using IP addresses.
- Protocols: IP, ICMP, ARP
Data Link Layer – Manages data transfer between directly connected devices.
- Protocols: Ethernet, Wi-Fi (802.11), MAC addresses
Physical Layer – Transmits raw bits over physical media (cables, radio waves).
- Examples: Ethernet cables, Fiber optics, Wireless signals

TCP/IP Model (Simplified Version)

The TCP/IP Model is a simpler version of OSI with four layers:

Application Layer – Combines OSI’s top three layers (e.g., HTTP, HTTPS, FTP).
Transport Layer – Manages connections (e.g., TCP, UDP). TCP has error checking, UDP does not. Data is split into packets (datagrams) which includes
Internet Layer – Routes data (e.g., IP, ICMP). ICMP is Internet Connection Management Protocol and includes traceroute and ping.
Network Access Layer – Physical and data link functions (e.g., Ethernet, Wi-Fi). How the packet is managed when received at rhe Lan of its destination. Packets are turned into frames and the switch forwards the right frames to the right IP address. Switch knows which MAC address has requested data and returns the data to the right one. The frame

Network Protocols

Protocols are rules and standards that define how data is transmitted across networks.

HTTP/HTTPS – Used for accessing websites.
FTP – Transfers files between computers.
SMTP/POP3/IMAP – Email communication. (Also X500)
TCP – Ensures reliable data transmission.
UDP – Fast, but no error checking.
IP – Assigns addresses to devices.
Ethernet/Wi-Fi – Used for local network communication.

Real-World Analogy for Network Layers – The Royal Mail Postal System

Think of network communication like sending a letter through a postal service. Each network layer has a role similar to steps in delivering a letter.

1. Physical Layer (Sending the Letter)

Represents the physical means of communication (wires, Wi-Fi signals, fibre optics).
In our analogy, this is like the postman’s satchel, postal vans, roads, and planes that physically transport your letter.

🔹 Example: Your letter is put into a satchel and carried by a van to the sorting office.

2. Data Link Layer (Stamping & Addressing)

Ensures that data moves correctly between directly connected devices.
Like adding a stamp and return address, ensuring your letter is accepted by the postal system.
Also checks for errors in transmission.

🔹 Example: If the letter is missing a stamp, it gets rejected.

3. Network Layer (Routing the Letter)

Determines the best route for data using an IP address.
Like a postal sorting office deciding which city or country to send the letter to.

🔹 Example: Your letter is sent from London to New York based on the address.

4. Transport Layer (Ensuring Delivery)

Manages the reliability of communication (e.g., TCP ensures delivery, UDP sends quickly but without confirmation).
Like choosing regular mail (UDP – fast but no tracking) or tracked mail (TCP – slower but reliable).

🔹 Example: If using TCP (tracked mail), the sender gets a notification when the letter arrives.

5. Session Layer (Managing the Conversation)

Establishes and maintains a session between devices.
Like a customer service call that stays connected while you get information.

🔹 Example: You keep sending letters back and forth in an ongoing conversation.

6. Presentation Layer (Translating the Message)

Converts data into a usable format (e.g., encryption, compression).
Like translating a letter from English to French if the recipient speaks a different language.

🔹 Example: If the message is encrypted (TLS), only the intended recipient can read it.

7. Application Layer (Receiving & Reading the Letter)

Directly interacts with the user (e.g., websites, emails, file transfers).
Like the recipient opening and reading the letter.

🔹 Example: The recipient reads a web page (HTTP) or opens an email (SMTP/IMAP).

Summary of the Postal System Analogy

OSI Layer	Postal System Equivalent
Application	Reading the letter (Web, Email)
Presentation	Translating the letter (Encryption, Formatting)
Session	Keeping communication open (Back-and-forth letters)
Transport	Ensuring delivery (Regular vs. Tracked Mail)
Network	Choosing the best route (Sorting Office)
Data Link	Addressing & Stamping (MAC Address, Error Checking)
Physical	Delivering the letter (Postman’s Satchel, Roads, Aeroplanes)

Coding

ClassAssistant

27/07/2025

Tablet-based tracker for in-Classroom use.

Tracking pupils mid lesson is hard. I am sure that as I become more accomplished as a teacher I can keep all this stuff in my memory, but I like objective records and I like React Apps. This therefore is a solution, orginally designed to support my pre-cataract surgery eyesight deficit, which gives me a list of students to call, to award credits or decredits to, to record any disciplinary actions or warnings which I might have to give and to record notes for each student. It also has flags to warn me of students who might need some kind of additional support, so I can check their confidential record and getn it right. It is designed to work on a tablet (such as my Surface Pro or an iPad) in landscape mode.

Here are some screenshots:

For confidentiality reasons, all data is protected behind a password system and data is transmitted between the server and client using a secure transport layer.

The user only has access to thir own data.

The main timetable page. This is test data, so don’t think I only work half the week! On each page there is a real-time clock, mainly because so many classrooms I am in have broken clocks and I want to just be able to glance at my tablet and see the time quickly.

This is the main in-class screen. It shows on the left the list of students to call. When they are called, and I record that with the “Call” button, they are moved to the bottom of the list. The red number indicates the number of times they have been called that lesson.

The + and – buttons add or subtract credits, and if I have a disciplinary issue, I can record the status of that by clicking on the discipline status. I can make any additional notes for each lesson and each one is timestamped and added to my student record.

Unfortunately in this scenario, I have had to give a minor warning to Velma to stop looking at Tik Tok in the lesson and so I have marked the first disciplinary stage and made a note in her record.

At the end of the lesson, the number of times called, the number of credits awarded and the disciplinary status at the end of the lesson is recorded in the student notes.

This gives me a record of cumultive achievement and will contribute to the reports on the students that I write.

For each class I can allocate a couple of images of the classroom layout for my seating plan. This is better and bigger than the ClassCharts one which is almost illegible.

(Obviously, I was just using any image I had to hand for testing)

In this Edit Class screen I can add students using a combination of search and a dropdown

When managing student records I can see a summary of all their notes (again useful for report-writing)

Given that a College might have a thousand students, the search facility is useful.

This project is uploaded to github at: https://github.com/SimonRundell/ClassAssistant

If anyone would like to try it out, then please let me know. I can provide the facility for a very very low price (I’m talking a tenner a year) or you can compile and implement it at your school for free. I’d be available to consult if you needed any help, support or advice on that.

Computer Science

Lesson Plan: Teaching Cybersecurity without touching technology

22/07/202523/07/2025

This is the lesson plan which got me the job. I couldn’t be sure of the resources I would have available, so I opted to teach about the CIA Model (set by the College) without anything more than a PowerPoint and a bunch of envelopes and cards. Use freely. Expand as you wish. Post improvements in the comments.

File Name: Microteach-CIA-model.pptx

PDF Loading...

The CIA Triad

Triad means 3, so there are 3 parts to the CIA triad model

Confidentiality, Integrity and Availability.

Let me illustrate with a bunch of envelopes…

Confidentiality:

Access Control

I have a list of people who are allowed the data. I ask a requesting student for their name and password which I check on a clipboard and if they are correct I give them the envelope.

I give another student the wrong password card and they ask 3 times which I reject and throw them out, showing that brute force password attacks can be foiled.

Authentication

Another student has a clipboard and a piece of paper with “Permission” on it. The requesting student gives their name and password to the clipboard student who gives me the “Permission” paper and I give the requesting student the envelope.

One issue can be the Man in the Middle attack with these two, so a student stands in between us and takes the envelope. He might not pass it on if he is a bad router and open it himself, so we must ensure the data is safe if it falls into the wrong hands with encryption.

Encryption

I have another envelope which I show as having something in code inside it. A student who is unauthorised asks for the envelope and I give them the one without the solution inside it. It doesn’t make sense. An authorised requesting student asks me for the envelope, and I give the one with the decrypted side to them, which they open and turn over which has the message on it decrypted.

Integrity:

Checksums

The requesting student asks for the envelope, I give them an envelope and tell them that the checksum of this data should be 1024, but on the outside of this envelope the checksum says “63”. I ask them if the checksum is correct and they will say no, so I give them an envelope with “1024” on it and ask if it is correct. If it is, they can open the envelope and get the data confident that it is correct.

Malware such as viruses and trojans often affect the checksum of a file, so the discarded envelopes could contain infected files.

Digital Signatures

I give the requesting student an envelope when they ask for it which I have signed. The first envelope isn’t my name. I ask them if it is correct and they say no, so they should discard it as it isn’t properly signed. I sign another one with my own signature and they can confirm it is correct and again can open it in the knowledge that it is correct.

Availability:

Backups

I create two envelopes. A student is given an envelope, and another student is encouraged to take it off them and throw it away. That is a cyber-attack. I ask him for the envelope, but it is lost. I have a second envelope somewhere, but I have to search for a moment before I hand it to them. This is restoring from a backup.

Redundancy

I create two envelopes. A student is given an envelope and then is told to throw it away. I ask him for the envelope, but it is lost. Luckily, I have a second envelope, and I give it to them immediately. This is redundancy.

These two deal with disaster recovery after systems failure, malicious damage or user error.

Denial of Service Prevention

The requesting student asks for the envelope, but all the other students start asking for the envelope at the same time, and I don’t know who to give it to. I ask the requesting student for a token, and they give me the card which says “Permission” on it and so I can give it to them, explaining that without the right token, a firewall or rate limiter will ignore all the other requests and only give the data to the right person.

Worksheet

Microteach Workksheet Download

Resources

Envelopes:

Basic x 5
Encrypted x 1
Encrypted with solution x 1
Checksum 63
Checksum 3794
Checksum 1024
Envelope for wrong signature
Envelope for right signature = 12 envelopes in total.

Cards:

Password card
Wrong password card
Permission
Example of my signature = 4 cards

Coding

Kallbak – student engagement in real time.

17/07/202517/07/2025

Many schools often ban Mobile Phones as a distraction, but in Computing we view them as tools – both a platform for development and a means of using technology to enhance our learning. In the more relaxed environment of Further Education (16+ in the UK), we do not automatically ban Mobiles, and I want to take it further to embrace them as a tool for engagement in the Classroom, Computer Lab and Lecture Theatre.

There are tools out there but they are almost exclusively web based and this doesn’t always chime well with the workflow as the teacher has to Alt-Tab to a web page to garner student reactions and answers. This has been my main issue with Mentimeter – a great product but with a cost and an interface limited by the web browser. I wanted something which worked within Microsoft PowerPoint, so I wrote Kallbak.

www.kallbak.com

Kallback is a low cost solution for Educators to have integrated interactions with the Students in their Classroom or Lecture Theatre. With the aid of a QR code or a 6-letter shortcode, students can answer an open question, a multiple choice question, create a word cloud or respond to an image. This is displayed in the Powerpoint Presentation Slide in real time.

Whenever someone like my Dance Teacher says “Does any one have any questions?” I always ask “What is the capital of Mongolia?” just shortly before she hits me.

What’s more, you can then ask Google Gemini AI to summarise and correct the answers given.

The Presenter/Teacher/Lecturer has his own control panel to enable and disable submissions to the page shown over his presentation screen.

…thus enabling them to Start the Presentation and run multiple slides with Kallbaks on them.

The whole add-in runs separately from your Slideshow template, so you can customise the look and feel of the displayed page to match your own needs.

The kallbak.com website enables you to create your own questions, use other submitted questions and create QR codes and the necessary links to be able to take Kallbaks from your classes.