Clouds & Puddles

Clouds are not always cute. Sometimes they are threatening, with the potential to damage, injure and even kill. Inderøy, Norway 2015-08-11. Photo: Patricia McLellan.

This weblog post is written to help people gain a better understanding of a house/ home/ residential computer network.

The Xample family with mother Ada, father Bob, cat Cat and daughter Deb are going to serve as an example. Currently, the family has the following equipment. Both Ada and Deb have iPhones, but Bob has a Samsung phone. In addition, Ada uses a Mac laptop, Bob has an old Acer desktop machine, while Deb uses a Chromebook laptop, that belongs to her school. The family is connected to the internet with a router, and they have an old Canon printer.

Some basic vocabulary

Sometimes, language can be confusing. To communicate about computers, people have to use words the same way, or misunderstandings will occur.

Users are people. Admittedly, there could be situations where something other than a human is a user. For example, at some point in the future Cat might be able to activate a feeding station. That would make Cat a user.

A computer, frequently known as a device, consists of hardware and software. Hardware is made up of physical/ mechanical components. Yet, these components will not work without software, a collection of instructions and associated data, that provide services.

Software capable of doing something is called a program. A computer program that is running/ working is usually referred to as a process. Software is written in a computing language that humans can read, and programmers can understand. This source code is then translated into machine code that the specific hardware on a machine can understand.

Operating systems are an important category of software. An operating system is the most fundamental program. It controls the functioning of the hardware and direct its operations. It manages the hardware including component parts, but hides the details from users. The Xample family, like most families, use several different operating systems. The iPhones use iOS, the Samsung phone uses Android, Ada’s Mac laptop uses macOS, Bob’s desktop uses Windows 7, Deb’s Chromebook laptop uses ChromeOS. Both the router and the printer also have their own special operating systems.


The term network can be used as either a noun or a verb. Begin with the verb, to network. This is a situation where two or more devices are able to exchange information with each other. The noun network refers to the sum of devices that are connected together. When networking, each connected device is referred to as a node. In the above case, an end node is connected to a network node, the iPhone and the router, respectively.

Nodes are connected to each other using data links. These links may be wired or wireless. The most common type of wired link is the Ethernet cable. The most common type of wireless link is WiFi. While some houses have only WiFi links, there can be good reasons for using cabled links if there is an opportunity for it.

Nodes don’t need to have a direct connection to each other, to be part of a network. Thus, one node could be located in Bergen, another in Detroit, and a third in New Westminster. This is an example of a wide area network (WAN). If the nodes are all located in the same cluster of buildings it is a local area network (LAN). For example, there could be several nodes inside a house, but one in a garage and another in a shed.

Computer professionals often use the terms client and server to describe a computing model. These are confusing terms. Fortunately, most people do not need to use them. The important thing to know is that a client either does local work or requests an external service. A server either provides that service directly to a client, or supervises an external supplier working on behalf of a client. Both terms can refer to either hardware or software. Focus on the software to understanding what is happening.

To help the Xample family transition to a network suitable for them, we are going to look at four challenges facing the family.

Challenge #1 Sending an email with an attachment

Ada has struggled for the past year to knit herself a sweater. It is finally finished, and she has taken a photo of it with the camera on her iPhone. She wants to send a copy of the photo to her brother Ely.

When Ada uses her phone to write an email, she is using an email client that is built into the iPhone. This client also allows her to attach the photo. When it comes time to send the email and its attachment, Ada uses an email server built into the iPhone that allows it to use the router to send out and receive emails.

In this example, there are two communicating devices, Ada’s iPhone and the family router. There is a network, even if it is small, simple and temporary. The two devices are connected using WiFi,

The router breaks both the email message and the photo into data packets. Each packet is equipped with a coded form of Ely’s email address. To find out where to send information, the router looks up an address using a routing table. If Ada receives an email from someone, the router will reassemble incoming data packets so that these can be understood. At home, most people use a digital subscriber line (DSL) or cable router connected to the Internet through an Internet service provider (ISP).

A DSL router typically integrates a modem. A modem sends packets of data across telephone lines, TV cables or optical fibers. A modem, by itself, does not provide the functions of a router.

Challenge #2 Printing

Ada wants to take a copy of the photo on her next visit to her grandmother Fay (1919 – ). Fay is not computer literate, but likes to decorate the walls of her room with photos. Before looking at what is happening in detail, we are going to learn a few more terms. To print a letter on paper, a print server will coordinate the printing process.

The main challenge with the family Canon printer is that it is so old that it doesn’t have any WiFi connection and won’t connect directly to the iPhone.

Ada connects her iPhone to her MacBook using the iPhone’s charger cable. She plugs the charging end into the iPhone, and the USB end into the MacBook. She then opens her Mac Photos app on her Mac laptop, clicks on Import, selects the photo she wants to transfer, clicks on Import (#) Selected, then finally clicks on Albums. Now the photo is on her laptop, and Ada can disconnect the charger cable.

To print the photo, Ada takes a USB cable, permanently attached to the printer, and plugs the other end into a USB port on her computer. Using a printer program and drivers, previously installed on her laptop, she can now print the photo. By plugging in the cable, Ada has once again set up a small, simple and temporary computer network. This time, it consists of the MacBook laptop and the Canon printer.

Challenge #3 A Permanent Network

Deb has her bedroom upstairs. If she wants to use the printer she has to take her Chromebook downstairs to attach it into the printer, using a USB cable. This is inconvenient. Most individuals/ couples/ families need system resources that can be shared by all/ many/ some users effortlessly. The basis for a permanent network may already be in place with the WiFi capabilities that are built into most domestic routers.

WiFi is a set of standards that allow devices to communicate with each other wirelessly. Devices that can use WiFi include desktops, laptops, smartphones, tablets, smart TVs, printers, digital audio players, digital cameras, cars and even drones.

Some families may consider replacing their printer with one that has WiFi capabilities. An alternative approach is to keep the printer, but to invest in a Network Attached Storage (NAS) server. A NAS can act as a print server, letting approved users print on a common printer.

Equally important, it can also act as a file server, so that common files can be stored in a central place and used by everyone. Such files include media files: video files, audio files, e-books; family photographs, and documents used by the entire family.

Everyone in the family will have to become users of the NAS, with their own log-in. Be sure to add an additional user, called Guest. Not all users are treated equally. Users have to log their client devices onto the system with a user name and a password, or some other approved form of identification. In this way, random visitors are prevented from accessing the server and its resources, without permission. Guest will typically be able to access the internet, but not able to access files on the NAS or use the printer.

A NAS can also backup personal files. These backups can be encrypted and password protected,so that they are unaccessible to others.

The Xample family decide that a QNAP TS-251A best suits their needs. They equip it with 4 TB of storage, which they regard as adequate for their needs. The printer can now be permanently connected to the NAS using a USB port, given access to users. Many printer drivers are instantly available, although older printers may require some effert to download appropriate drivers. If the printer is compatible with the NAS, it will display a message to confirm that the printer is connected.

Challenge #4 Clouds & Puddles

The Xample family now have 3 smartphones, 2 laptops, 1 old desktop, 1 printer, 1 router and 1 NAS. The NAS can function as a print server and a file server. It is also a media centre, serving videos and audio.

Computer hardware manufacturing companies are always keen to describe old products with new names. They are always looking at ways to make their rather dull equipment seem more important than it actually is. Edge and cloud computing are two such names.

An edge computer, in dataspeak, is a local server device at the edge of the internet, hence the term. Many will find it difficult to distinguish an edge computer from any other server, because almost everything today is connected to the Internet. However, in years past, many local servers were only connected to local devices using a local area network (LAN) typically wired with Ethernet cable. There was no connection to the outside world.

The cloud, in dataspeak, refers to someone else’s server. Companies that offer cloud services to the public often claim that they do the heavy lifting, storing and safeguarding data. This is not always the case. Sometimes they lose data. Sometimes they lend data to others. They might even keep a copy of it, when you ask to have it back. The misuse of data held in trust, may have economic as well as other consequences. Adobe, Amazon and many other companies are very keen for consumers to visit a nearby cloud, and use software as a service. This is the most profitable for them. Using a cloud can be expensive.

For a short period, just after cloud computing came into vogue, it became fashionable to name non-cloud servers after bodies of water. Large businesses might refer to their in-house servers as lakes. Referring to a server at home as a lake verges on the pretentious. Modesty dictates referring to smaller bodies of water: a personal (puddle) server, a nuclear family (pool) server or an extended family (pond) server.

Fun Assignment: The reader is asked to distinguish a carbon based error from a silicon based error. Assistance with this problem can be found here.


As we enter 2019, Cliff Cottage is transitioning.

Mothership has been selected as the generic name for the constellation of products and services provided by the central server rack at Cliff Cottage. While cloud is a buzzword referring, especially, to somebody else’s server, we tried to find a specific cloud variety that we could use for a name. Our choice refers to one of the most beastly type of clouds found on earth.

Mothership Clouds, also referred to as Supercell Thunderstorms, bring long-lived, dangerous storms with strong updrafts and rotation. They generate violent (F2-F5) tornadoes, cause downburst damage and produce large hailstones. Warm, humid conditions promote rapid lifting of air, quick changes of wind speed and/or direction increase rotational speed.

Mothership Cloud (Photo: Nevadanista)

A mothership is also a large vehicle/ vessel/ craft that leads, serves or carries other smaller vehicles/ vessels/ craft, including aircraft or spacecraft. For our purposes, it is a large digital device serving a number of smaller devices/ computers/ peripherals.

For the past 14 years, we have used an ADSL-based internet, which was a dramatic improvement over a dial-up modem. We have now gone over to fiber-optic broadband and cut out our landline. Our handheld personal devices, aka cell phones, are being updated to more advanced variants. We have replaced our inkjet printer, with a laser printer. CAT 6A cables are being installed throughout the house. While our network speed is currently 50 Mb up and down, increasing speeds to 1 Gb is simply an email away. So this is probably the last major communications upgrade in our lifetime.

In another post, a clustered NAS (Network Attached Storage) server system has been discussed (2018-06-21). This is still the goal. While we are not there yet, we are replacing our current NAS, with one designed and built by Alasdair. While we previously maxed out at 24 TB of data, the new NAS will start off with 40 TB. It is expandable to 120 TB. While many of the components are old and used, they are more appropriate for our needs. Typically, they are commercial products, produced by Cisco, but made redundant in commercial environments.

It is not my intention to publish further details about the Mothership in this web-log, at the moment. Rather, detailed information will be made available after a period of implementation and testing, to ensure that proposed solutions work properly.

If you, your close friends or family have developed technological solutions to modern problems, please consider making them freely available, and publishing them in a web-blog, or through other channels.

A Clustered NAS

A minimal storage and backup solution

Thirty-five years of digital data on multiple vintages of media including 8″, 5″ and 3 1/2″ floppy disks, thirty years of music on CDs, and twenty years of films on DVDs, have already met, or will soon meet, their final destiny. All of this data takes a lot of space, and is never used. Why? We own no computer with floppy disk drive, no stereo with CD player, or television with DVD player. In fact, we don’t even own a television or a stereo. While my desktop machine still has a DVD-drive that will play these, all of the other machines in the house lack this capability.

I will not repurchase content in yet another format. I will not subscribe to Spotify or Netflicks to gain access to content already purchased. Most CD and DVD content has been copied to a server, that can be accessed by any machine in our house. This NAS, variously described as network attached storage or a network attached server,  also backs up files stored on more personal devices. If a machine suffers disk failure, or theft, documents will still exist on the NAS.


Encryption encodes information so only authorized people can access it. It makes content unintelligible to a potential interceptor. Privacy is important, and encryption is one way to ensure private data remains private.

Some terms: plaintext = the intended information; cipher = an encryption algorithm;  ciphertext = text generated by a cipher; encryption key = encryption scheme generated by an algorithm.

An authorized recipient can easily decrypt the message with the key provided.

RAID (Redundant Array of Independent Disks, originally Redundant Array of Inexpensive Disks) is data storage technology formats, allowing several physical disk drives to combine into one or more logical units. It offers data redundancy as well as improved performance. Many users prefer RAID 6. This requires the use of four drives. However, any two of these can fail. A single drive failure results in reduced performance, until the failed drive has been replaced.

That is fine, if the failure is restricted to a single computer. What happens if there is a catastrophic event, destroying the house? The correct answer is, nothing happens, or at least nothing positive, because there is nothing left to rebuild a file system from. If one wants to rebuild these collections, one will have to have a NAS with a distributed file system running simultaneously on multiple servers. This is referred to as a clustered NAS. With a clustered NAS, all files can be accessed from any (and every) cluster node.

The Cloud, of course, can provide backup services, on multiple servers. However, the shutdown of in 2012, should be reason enough for everyone to avoid relying on cloud services.

Another proposed solution is to rely on family and friends, people you know and trust, to provide these services. I have close family living in four cities in three countries on two continents. This could mean I could then enter into agreement with one or more of these to backup my data in an encrypted format, while I backup theirs. They won’t have meaningful (that is, unencrypted) access to my data, and I won’t have meaningful access to theirs.

An Inexpensive NAS

For about USD 55 or NOK 500, the ODROID-HC1 and ODROID-HC2 can be bought. These are single board computers designed as network attached storage (NAS) servers, so that users can make their own home cloud. This system is useful for a single user, a family or other groups of people. Both hard disk drives and solid state drives can be used. A Western Digital Red 1TB drive costs about USD 65 or NOK 550.

ODROID HC2 (Home Cloud) single board computer, specifically designed to be used as a NAS controller. (Photo:

ODROID-HC1, with Samsung SSD attached. (photo:

An ODROID-HC2 with 8GB microSD card for OS installation, a 3 1/2″ hard disk drive, 12V/2A power supply, Ethernet cable, case, Wifi antenna. A router is also needed, but not shown. (photo: