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Χρήση υπολογιστή Python is an advanced programming language that is object-oriented, interpreted, and built on flexible and robust semantics. Why learn it? Python is easy to learn and lets programmers quickly integrate systems as scripting or glue language. It is also suited for Rapid Application Development, such as: Writing games for their inner logic, comprising Artificial Intelligence factors. NASA uses Python as a standard scripting language in its Integrated Planning System. Its Features are: Easy to learn and read. Associated web structures for developing internet-based applications. Has a free interpreter and standard library accessible in source or binary on major platforms. Who uses it: Python developers, software engineers, back end developers, Python programmers Used by employers in information technology, engineering, professional services, and design.

Choosing a Tripod 1. Weight A tripod’s weight should be considered from two perspectives. Will it be carried around? Used indoors? Or both? ​ I have: 2 x heavy tripods for indoor use. 4 x small tripods for tabletop, placing on low walls or a bonnet of a car. 1 x medium weight tripod for outdoor use - Remember that someone is going to need to carry it around. Mine attaches to my Bergan/rucksack which makes it easier to carry long distances. ​ 2. Stability Weight does not always equal stability. If possible, test the tripod with the camera on it along with the largest lens, light, flash, and microphone. Test it fully extended to see how stable it is. Will it be sturdy on a windy day? Will it take the knock of someone bumping it on the way past? Has it got hooks for weights? ​ 3. Leg Locks There is a lot of variation between manufacturers when it comes to the mechanisms used for locking legs into place. Often, it comes to personal preference, but secure locks are essential. My main tripods are Manfrotto, they offer quick-release locks that are stable, and I have found reliable. ​ 4. Leg Sections The number of sections used to alter the height on tripods can be a factor. If they have two sections, they will be longer when they are collapsed. Two is good because there is less playing around with extending and locking the legs, while three sections provide a more compact tripod when folded. ​ 5. Height How long is a piece of string? Depending on the type of photography, the height requirements of a tripod will vary. What is the maximum height needed? But also, how it operates at its minimum, and how big it is when it is all folded. In all honesty, having a tripod one can look into the camera’s eyepiece without having to bend is a bonus, there is nothing worse than a full day of leaning over to check the framing shots. ​ 6. Tripod Heads Tripod heads can either be bought with a tripod as a complete set or separately. One key aspect to consider about a tripod is how the camera attaches to it. There are numerous options available, and it is worth planning and considering the options, as the tripod head not only keeps your camera on the tripod but will determine how much flexibility you have once it is attached. ​ My preference is the quick release Manfrotto tripod heads, they are well built and extremely sturdy. Each of my cameras and GoPros have a Manfrotto tripod head fitted, so I can easily swap cameras or tripods. ​ The two main types of tripod heads are: ​ Ball and socket – are great for flexibility and moving your camera around, but I find them fiddley. ​ Pan and tilt – are great for locking into position and are usually more affordable. They are not as fluid to move around and take getting used to, but I prefer them.

Χρήση υπολογιστή Έμαθα να χρησιμοποιώ υπολογιστές από νωρίς, τώρα έχω διδακτορικό. Στο Computing, Software Programming, Hardware Repair, Website Design, και εργάστηκε για έναν μεγάλο προγραμματιστή λογισμικού και ως ανώτερος μηχανικός υπολογιστών. Έχω μερικά μηχανήματα, τα οποία χρησιμοποιούνται κυρίως για: Σχεδιασμός λογισμικού Προγραμματισμός Γράφοντας προγράμματα ηλεκτρονικής μάθησης Τα μυθιστορήματά μου Σχεδιασμός ιστοσελίδων Επεξεργασία φωτογραφιών και βίντεο Μεσα ΚΟΙΝΩΝΙΚΗΣ ΔΙΚΤΥΩΣΗΣ Ο πρώτος υπολογιστής μου ήταν το ZX Spectrum. ήταν ένας προσωπικός υπολογιστής 8 bit που κυκλοφόρησε στο Ηνωμένο Βασίλειο το 1982 από την Sinclair Research. Ο υπολογιστής Spectrum κυκλοφόρησε σε οκτώ διαφορετικά μοντέλα, που κυμαίνονται από το αρχικό επίπεδο με 16 KB RAM, έως το ZX Spectrum +3 με 128 KB RAM εφοδιασμένη με μια ενσωματωμένη μονάδα δισκέτας. Άλλοι πρώτοι οικιακοί υπολογιστές που στοχεύουν σε ένα mainstream κοινό στο Ηνωμένο Βασίλειο ήταν οι εξής: Το Commodore 64 Δράκος 32 BBC Micro Amstrad CPC Έμαθα να προγραμματίζω σε διάφορες γλώσσες υπολογιστών χρησιμοποιώντας τα παραπάνω συστήματα. Το 1991, μετανάστευσα σε υπολογιστή με έκδοση Microsoft με Windows 3.0. Ήταν μια βελτίωση στα προηγούμενα συστήματα που έμαθα, αλλά το Win 3.0 δεν είχε δυνατότητες πολυμέσων και δικτύου, οπότε το Win 3.0 αντικαταστάθηκε γρήγορα με το Win 3.1 και η βελτίωση της εμφάνισης της διεπαφής ήταν τεράστια.

Programming Editing Software What is programming editing software? They are a computer program that edits plain text and called text editors. Text editing software is incorporated with operating systems and software development packages, they are used to write or modify configuration files, documentation files, and programming language source code. ​ Here are some of the programming editing programs I use: Vim is a highly configurable text editor built to create and change any kind of text very efficiently. It is included as ‘vi’ with most UNIX systems and Apple OS X. Vim is rock stable and is continuously being developed into a better text editor. ​ Features: Persistent, multi-level undo tree. Extensive plugin systems. Support for a myriad of programming languages and file formats. Powerful search and replace abilities. Integrates well with many tools. Notepad++ is a popular free-to-use code editor written in C++. It uses pure win32 API which offers a larger execution speed and small program size. It only runs in the MS Window's environment but uses a GPL License. ​ Features: This text editor supports syntax highlighting for languages like PHP, HTML, CSS, and JavaScript. Auto-completion: Word completion, Function completion. Macro recording and playback. User-defined Syntax highlighting and folding. Customizable GUI. Multi-view and Multi-Language support. Visual Studio Code is an open-source (Free) code editing software developed by Microsoft. This free text editor offers built-in support for TypeScript, JavaScript, and Node.js. It is autocompleted with IntelliSense features provides smart completions based on variable types, essential modules, and function definitions. ​ Platforms: Mac, Windows, Linux. ​ Features: Easy working with Git and other SCM (Software Configuration Management) providers. Code refactoring & debugging. Easily extensible and customizable. Brackets is a free lightweight tool developed by Adobe. It allows you to toggle between your source code and the browser view. ​ Platform: Mac, Windows, Linux ​ Features: Quick Edit UI feature puts context-specific code and tools inline. Offers live preview, pre-processor support, and inline editors. Pleasant-looking User Interface (UI). A specifically developed tool for macOS Comes with the inbuilt extension manager. Dreamweaver is an Adobe software editor that allows users to create, code, and manage dynamic websites easily. Users can build responsive websites that adapt to fit any screen size, whether it is on a computer or handheld device. You can preview your websites and edit in real-time to ensure your pages look and work the way you want before you publish. It provides access code hints so users can quickly learn and edit HTML, CSS, and other web standards, and it uses visual aids to reduce errors and speed up site development. I have been using Dreamweaver for countless years and have found it to be a reliable robust editor. But it is expensive and out of reach for many non-professional users.

Raid 5 to 10 RAID 5, 6 and 10 RAID 5 is block-level striping with distributed parity that allocates parity with the data and needs all the HDDs but one to be present to operate. In this configuration, the array is not destroyed by a single drive failure. When an HDD fails any successive reads can be calculated from the distributed parity, so, the HDD failure is masked from the end-user. RAID 5 requires at least three disks and is often and is reliable a good system to use because if an HDD fails your data is safe on the other HDDs. ​ Also, if you replace the failed HDD with a new HDD it will automatically take over the function of the failed HDD. RAID 6 is block-level striping with double distributed parity that provides fault tolerance up to two failed HDDs. This makes larger RAID groups more practical, particularly for high-end systems. These days this is increasingly significant as large capacity HDDs prolong the time needed to recover from a single HDD failure. ​ Similar to RAID 5 , a single HDD failure results in reduced performance of the total array until the failed HDD has been replaced and the data has been rebuilt. RAID 10 , sometimes mentioned as RAID 1+0 mirroring and striping occurs. Data is written in stripes across primary disks that have been mirrored to the secondary disks. ​ This is the best RAID system, one I have used for a long time.

Resistors Οι αντιστάσεις είναι παθητικά δύο τερματικά ηλεκτρικά εξαρτήματα που επηρεάζουν την ηλεκτρική αντίσταση σε ένα στοιχείο κυκλώματος. Στα ηλεκτρονικά κυκλώματα, οι αντιστάσεις χρησιμοποιούνται για τη μείωση της ροής ρεύματος, τη ρύθμιση των επιπέδων σήματος, τη διαίρεση τάσεων, τα ενεργά στοιχεία μεροληψίας και τον τερματισμό γραμμών μεταφοράς, αλλά έχουν επίσης άλλες εφαρμογές. Υπάρχουν πολλοί τύποι αντιστάσεων που χρησιμοποιούνται σε ηλεκτρονικά κυκλώματα. Οι αντιστάσεις είτε ελέγχουν τη ροή του ρεύματος είτε παράγουν πτώση τάσης. Για να γίνει αυτό, μια αντίσταση πρέπει να έχει κάποια μορφή τιμής «αντίστασης» ή «αντίστασης». Επομένως, οι αντιστάσεις διατίθενται σε μεγάλη γκάμα τιμών αντίστασης από κλάσματα Ohm (Ω) έως εκατομμύρια Ohms. Όταν το σώμα της αντίστασης είναι αρκετά μεγάλο για να διαβάσει την εκτύπωση, όπως αντιστάσεις ισχύος, τιμή αντίστασης, ανοχή και ονομαστική ισχύς τυπώνονται γενικά στο σώμα της αντίστασης με τη μορφή αριθμών ή γραμμάτων. Αλλά οι περισσότερες αντιστάσεις είναι μικρές, αυτές οι προδιαγραφές εμφανίζονται ως έγχρωμες ζώνες που υποδεικνύουν τις τιμές αντίστασης και ανοχής τους μαζί με το φυσικό μέγεθος της αντίστασης που υποδεικνύει την βαθμολογία της ισχύος. Υπολογισμός τιμών αντιστάσεων Η «αριστερή», πιο σημαντική έγχρωμη ζώνη είναι η ζώνη που είναι πλησιέστερη σε ένα καλώδιο σύνδεσης με τις χρωματικές κωδικοποιημένες ζώνες να διαβάζονται από αριστερά προς τα δεξιά ως εξής: Ψηφίο, Ψηφίο, Πολλαπλασιαστής = Χρώμα, Χρώμα x 10 χρώμα σε Ωμ (Ω) Για παράδειγμα, μια αντίσταση έχει τις ακόλουθες χρωματικές ενδείξεις. Η τέταρτη και η πέμπτη ζώνη χρησιμοποιούνται για τον προσδιορισμό της ποσοστιαίας ανοχής της αντίστασης. Η ανοχή αντίστασης είναι ένα μέτρο της διακύμανσης της αντίστασης από την καθορισμένη τιμή αντίστασης και είναι αποτέλεσμα της διαδικασίας κατασκευής και μεταφέρεται ως ποσοστό της «ονομαστικής» ή προτιμώμενης τιμής της. Οι τυπικές ανοχές αντίστασης για αντιστάσεις φιλμ κυμαίνονται από 1-10% ενώ οι αντιστάσεις άνθρακα έχουν ανοχές έως και 20%. Οι αντιστάσεις με ανοχές κάτω του 2% ονομάζονται αντιστάσεις ακριβείας με τις αντιστάσεις χαμηλότερης ανοχής, με αποτέλεσμα να είναι ακριβότερες. Η πλειοψηφία των πέντε αντιστάσεων ζώνης είναι αντιστάσεις ακριβείας με ανοχές είτε 1-2%, ενώ οι περισσότερες από τις τέσσερις αντιστάσεις ζώνης έχουν ανοχές 5%, 10% ή 20%. Ο χρωματικός κωδικός που χρησιμοποιείται για να δηλώσει την ονομαστική ανοχή μιας αντίστασης δίνεται ως ένα από τα ακόλουθα: Εάν η αντίσταση δεν έχει τέταρτη ζώνη ανοχής, τότε η προεπιλεγμένη ανοχή θα είναι 20%. Αντίσταση με σημάδια κώδικα

Memory (RAM) Memory (RAM) – RAM is short for ‘Random Access Memory’ and while it may sound enigmatic, RAM is one of the most important elements of computing. It is the super-fast and temporary data storage space that a computer needs to access right now or in the next few moments. DDR vs SDRAM ​ DDR (DDR1), DDR2, DDR3, DDR4, and DDR5 are newer variations of the older SDRAM. SDRAM and DDR RAM are memory-integrated circuits used in computers. SDRAM is a generic name for many types of DRAM that synchronizes with the microprocessor’s (CPU) clock speed. ​ DRAM had an asynchronous interface; it responds as quickly as possible to changes in control inputs. Both SDRAM and DDR RAM have a synchronous interface, so it waits for a clock signal before responding to control inputs and is therefore synchronized with the computer’s system bus. ​ This allows the memory chip to have a more complex pattern of operation than an asynchronous DRAM. This is also why the speed of SDRAM and DDR RAM is rated in MHz rather than in nanoseconds (ns). ​ SDRAM usually refers to the first generation of synchronous DRAM, so is slower than succeeding generations of DDR because only one word of data is transmitted per clock cycle (single data rate). The second generation of synchronous DRAM memory chips was DDR (or DDR1). ​ DDR is short for Double Data Rate. It is a memory that uses both the rising and falling edge of the system clock that has the potential of doubling the speed of the memory. So, the chip reads or writes two words of data per clock cycle. The DDR interface achieves this by reading and writing data on both the rising and falling edges of the clock signal.

Linux Command Line The Linux command line is a text interface to your computer, it is a computer program that interprets commands. Allowing users to execute commands by manually typing at the terminal or has the ability to automatically execute commands which were programmed in ‘Shell Scripts’. The shell is a program that takes commands from the keyboard and presents them to the operating system to perform. On most Linux systems a program called ‘bash’ (Bourne Again Shell) acts as the shell program. Besides bash, other shell programs include ksh, tcsh, and zsh. ​ A terminal is a program called a ‘ terminal emulator ’. This program opens a window and lets you interact with the shell. There are several different terminal emulators, most Linux distributions supply a few, popular terminals are: ​ Gnome-terminal - is a free open-source terminal emulator for the GNOME desktop environment, terminal emulators allow users to access a UNIX shell while remaining on their graphical desktop. Like most of the terminal emulators in this group, it supports coloured text, a variety of themes, transparency, mouse interaction, multiple tabs, and the automatic rewrapping of text upon resizing. As well as supporting multiple profiles. ​ Konsole or Console - is a free open-source terminal emulator that is part of KDE and ships with the KDE desktop environment. Konsole is the default terminal emulator shipped with KDE. Being a KDE component, it provides the embedded terminal for many other KDE applications, including Konqueror, KDevelop, and Kate. Its features are like the default GNOME terminal but have enhanced bookmarking functions for directories and SSH. It also offers split terminals. ​ xterm - In computing, xterm is the standard terminal emulator for the X Window System. Users may have many different requests of xterm running at once on the same display, each of which provides independent input/output for the process running in it (normally the process is a Unix shell). ​ rxvt - is an acronym for ouR eXtended Virtual Terminal, it is a terminal emulator for the X Window System, and in the form of a Cygwin port, for Windows. ​ Guake – is one of a few terminal emulators with a ‘ drop-down ’ style interface, emerging from the top of your screen with the press of a hotkey. ​ Tilde – is another Quake-style drop-down terminal emulator, designed for Gtk. Its name is taken from the tilde key, the default key for invoking the Quake terminal. Tilda's default interface is extremely minimal, with no window title or border, but this can be changed in the preferences. And has several options for everything from setting key bindings, setting default size and colour, and scrolling preferences. ​ Terminator - is a terminal emulator designed to make positioning terminals within a single-window easier, it features including several key-bindings, saving of layouts, and the ability to type to multiple terminals at the same time. Mirroring much of the behaviour of the GNOME terminal. ​ Yakuake - another drop-drown terminal emulator, is part of the KDE family. If you like Konsole but prefer the Quake-style approach, this is terminal may be an option. ​ To start a terminal search through the list of programs to see if anything looks like a terminal emulator: ​ With KDE - the terminal program is called ‘ konsole ’ With Gnome - it is called ‘gnome-terminal ​ Opening a Linux terminal ​ To open the terminal, press : ​ Ubuntu and Mint - Ctrl+Alt+T gnome-terminal - press Alt+F2 , type in gnome-terminal , and press enter Raspberry Pi - type in lxterminal Linux Commands Basic Commands: pwd (password) - When opening a terminal, you are in the home directory of your user. To know which directory you are in, you can use the ‘ pwd ’.command. It provides the absolute path, which means, the path that starts from the root. The root is the base of the Linux file system. It is denoted by a forward slash ( / ). The user directory is usually something like ‘ /home/username ’. ​ ls (list) - use the ‘ls’ command to know what files are in the directory you are in, but to view hidden files use the command ‘ ls -a ’. ​ cd - Use the ‘cd’ command to go to a directory. So, if you are in the home folder, and you want to go to the Documents folder, then you can type in ‘ cd Documents ’, keep in mind, this command is case sensitive, so if you type documents, it will not work, you must type in the exact name of the folder. If you just type ‘ cd ’ and press enter, it takes you to the home directory. To go back from a folder to the folder before that, you can type ‘ cd .. ’. The two dots represent back. ​ mkdir & rmdir - use the mkdir command when you need to create a folder or a directory. For example, if you want to make a directory called ‘ Music ’, then you can type ‘mkdir Music’. Remember, as told before, if you want to create a directory named ‘ Music Albums ’, then you can type ‘ mkdir Music\ Albums ’. Use rmdir to delete a directory. But rmdir can only be used to delete an empty directory. To delete a directory containing files, use rm . ​ touch - the touch command is used to create a file. It can be anything, from an empty txt file to an empty zip file. Like, ‘ touch new.txt ’. ​ rm (remove) - use the rm command to delete files and directories, typing ‘ rm -r’ will delete just the directory. It deletes both the folder and the files it contains when using only the rm command. ​ man & --help - the man command allows users to find out more about a certain command and how to use the man command. It displays the manual pages of the command. For example, ‘ man cd ’ shows the manual pages of the cd command . Typing in the command name and the argument helps it show which ways the command can be used, such as ‘ cd –help ’. ​ cp (copy) - the cp command to copies files through the command line. It has two arguments: ​ Location of the file to be copied Where to copy ​ mv (move) - the mv command moves files via the command line. It can also be used to mv command and rename a file. Such as, if we want to rename the file ‘ tinder ’ to ‘ fire ’, we can use ‘ mv tinder fire ’. It takes the two arguments, just like the cp command. ​ locate - The locate command locates a file in a Linux system, like the search command in Windows. This command is useful when you do not know where a file is saved or the actual name of the file. Using the -i argument with the command helps to ignore the case (it is not case sensitive). So, if you want a file that has the word ‘wolf ’, it gives the list of all the files in your Linux system containing the word when you type in ‘ locate -i wolf ’. If you remember two words, you can separate them using an asterisk (*). Like, to locate a file containing the words ‘wolf" and ‘ this ’, you can use the command ‘ locate -i *wolf*this ’. ​ Intermediate Commands ​ echo - the echo command allows us to move some data, typically text into a file. For example, if you want to create a new text file or add to an already made text file, you just need to type in, ‘echo beware, the wolf is at the door >> new.txt ’ . You do not need to separate the spaces by using the backward slash here because we put in two triangular brackets when we finish what we need to write. ​ sudo - is a widely used command in the Linux command line, sudo means for ‘SuperUser Do ’ . So, if you want any command to be done with administrative or root privileges, you can use the sudo command. For example, if you want to edit a file like viz. alsa-base.conf, which needs root permissions, you can use the command ‘ sudo nano alsa-base.conf ’ . You can enter the root command line using the command ‘ sudo bash ’ , then type in your user password. You can also use the command ‘ su ’ to do this, but you need to set a root password before that. For that, you can use the command ‘sudo passwd ’ ( not misspelled, it is abbreviated to passwd ). Then type in the new root password. ​ cat - the cat command is used to display the contents of a file. It is usually used to easily view programs. ​ nano, vi, jed - nano, and vi are installed text editors in the Linux command line. The nano command text editor denotes keywords with colour and can recognise most languages, vi is simpler than nano. You can also create a new file or modify a file using this editor. Like, to make a new file named ‘ cub.txt ’, you can create it by using the command ‘ nano cub.txt ’. You can save your files after editing by using the sequence Ctrl+X, then Y (or N for no). ​ tar - use tar to work with tarballs (files compressed in a tarball archive) in the Linux command line. It can compress or un-compress different types of tar archives like .tar , .tar.gz , or .tar.bz2 . It works based on the arguments given to it, like, ‘ tar -cvf ’ for creating a .tar archive, -xvf to untar a tar archive, -tvf to list the contents of the archive. ​ df - use the df command to see the available disk space in each of the partitions in your system. Type ‘ df ’ in the command line to see each mounted partition and their used/available space in % and in KBs. If you want it shown in megabytes, you can use the command ‘ df -m ’ . ​ du (disk usage) - the du lets you know the disk usage of a file in your system. If you wish to know the disk usage for a particular folder or file in Linux, you can type in the command ‘ df ’ and the name of the folder or file. So, if you want to know the disk space used by the documents folder in Linux, you can use the command ‘ du Documents ’ . You can also use the command ‘ ls -lah ’ to view the file sizes of all the files in a folder. ​ zip, unzip - is used to compress files into a zip archive, and unzip to extract files from a zip archive. ​ uname - Use uname to show the information about the system your Linux distro is running. Using the command ‘ uname -a ’ prints most of the information about the system. This prints the kernel release date, version, or processor type. ​ apt-get - using apt allows users to work with packages in the Linux command line. Users use apt-get to install packages. This requires root privileges, so the sudo command will also be required. Such as, if you want to install the text editor vim , type in the command ‘ sudo apt-get install vim ’ . Similarly, any package can be installed this way. However, it is prudent to update your repository each time you want to install new packages. This can be done by typing ‘ sudo apt-get update ’ . Upgrading the system you type ‘ sudo apt-get upgrade ’, and for distro upgrades, type ‘ sudo apt-get ‘ dist-upgrade ’ . The command ‘ apt-cache search ’ is used to search for a package. If you want to search for one, you can type in ‘ apt-cache search vim ’, but this does not require root command. ​ chmod - use chmod to make a file executable and to change the permissions granted to it in Linux. If you have a python code-named dog.py on your computer. You will need to run ‘ python dog.py ’ every time you need to run it. Instead of that, when you make it executable, you only just need to run ‘ dog.py ’ in the terminal to run the file. To make a file executable, you can use the command ‘ chmod +x dog.py ’ . You can use ‘ chmod 755 dog.py ’ to give it root permissions or ‘ sudo chmod +x numbers.py ’ for root executable. ​ ping - is used to check your connection to a server, it is a computer network administration software utility that tests the reachability of a host on an Internet Protocol (IP) network. When ‘ ping google.com ’ is typed it checks if it can connect to that server and come back, and also measures the round-trip time then gives displays the details about it. Most users use this command to check their internet connection. If it pings the server the internet connection is active. ​ hostname - hostname provides your name in your host or network. It displays your hostname and IP address. Typing ‘ hostname ’ gives the output. While typing in ‘ hostname -I ’ gives you your IP address in your network.

Operating Systems An operating system (OS) is the system software that manages computer hardware and software resources and provides common services for computer programs. Most computer programs require an operating system to function. Since the early days of Windows 3.0 and 3.1, operating systems for home or business users have evolved into more reliable and complex operating systems capable of undertaking countless tasks. Even so, most operating systems and software programs are upgraded rather than rewritten from the ground up. This lack of commitment and foresight limits operating systems development. What we see in science fiction (SciFi) films is not commonplace in our homes. Yet we have the technology and skills to push operating systems into that age, where: ​ ​ Walls become displays in every room. Desktop computers are integrated systems that communicate with our home and business devices, such as store cupboards, fridges, entertainment, lighting, heating, and security. Voice recognition and instant language translation are commonplace. Contact lenses become the new interfaces and remove the need for mobile phones, tablets, or laptops. ​ The four most common operating systems are: ​ Microsoft Windows Apple’s macOS Linux (Although this is not a commonly used OS for PC manufacturers) Android ​ Methods to identify an OS ​ If you do not know what version of Windows being used, press the Windows key at the bottom of the keyboard, which looks like four squares and the R key at the same time to open the Run dialog box, then, Type in ‘ winver ’, then click Okay . A window should open called About Windows that tells you which operating system you are using. ​ Open the Start menu by clicking the bottom left-hand corner of your screen. If you see a search text box, select it, and then type about or about your pc . If you do not see a search text box, then just start typing about or about your pc . Select About your PC.

System Recovery Mode Windows Recovery Mode - MS Windows 10/11 allows a recovery USB Drive to be generated. Manufacturers of pre-built desktops and laptops have their own recovery media embedded into the system, so pressing the F11 key may not work on all PCs as there is no one standard and many manufacturers use F9, F10, or F12 keys to enter recovery mode. ​ Press the Windows tab and type ‘Recovery Media’ then follow the instructions. Create a bootable USB drive using the Command Line (CMD). ​ When needed insert ‘Recovery USB drive’, and then restart your computer and press F11 before the MS Windows logo appears. ​ However, true recovery will put the computer back to its factory state and you will lose data and some programs. If you want to revert and completely clean the computer this option may be appropriate. I also use the ‘system Image’ option as this will back up the data and programs installed. ​ Various options for recovery. ​ Enter Recovery Mode using the Start Menu option: ​ The Start menu’s Restart option provides one of the most reliable methods for entering recovery mode. Click the Start button in Windows 10/11. Then click the Power button. Press and hold the Shift key. Then click Restart while holding the Shift key. After that, select Troubleshoot and Advanced options on the blue menu. ​ Enter Recovery Mode with a bootable USB drive: ​ Users can enter recovery mode with a bootable USB drive that they can install (or reinstall) Windows 10 with. First, users will need to set up the bootable USB drive with the Windows Recovery option or Image file. Users will also need to configure their PCs to boot from USB drives first by adjusting the BIOS or UEFI settings. Thereafter, insert a bootable USB drive into a PC’s USB slot. Turn the laptop or desktop on. Then a Windows Setup window will appear if the PC is configured to boot from USB drives. Click Next on the Windows setup window. Select the Repair your computer option. Then select Troubleshoot and click on Advanced Options to enter the Advanced Start-up Options menu. ​ Select the Restart now option: ​ Users can also get to Advanced Start-up Options by clicking the Restart now an option in Settings. Click the Type here to search button on Windows 10’s taskbar. Enter the keyword recover in the search box to find the Recovery option. Click Recovery to open the window shown directly below. Click the Restart now button under Advanced start-up. The PC will restart to the Choose an option menu from which users can select Troubleshoot and then Advanced options. ​ Enter Recovery Mode using Command Prompt. ​ The Command Prompt provides another way to access recovery mode. Type cmd in Windows Search and click on Run as an administrator to start Command Prompt. Input the following command and press Enter: shutdown /r /o Click Close on the You are about to be signed out a prompt that appears. Thereafter, select Troubleshoot and Advanced options after the restart. ​ So, there are few ways users can enter Windows 10’s recovery mode. When users enter the recovery mode, they can then utilise the System Restore, Command Prompt, System Image Recovery, and Start-up Repair utilities. Create a bootable USB flash drive using CMD. ​ Insert a USB flash drive into a running computer. Open a Command Prompt (CMD) window as an administrator. Type diskpart . In the new command line window that opens, to determine the USB flash drive number or drive letter, at the command prompt, type list disk , and then click ENTER . The list disk command displays all the disks on the computer. Note the drive number or drive letter of the USB flash drive. At the command prompt, type select disk , where X is the drive number or drive letter of the USB flash drive, and then click ENTER . Type clean , and click ENTER . This command deletes all data from the USB flash drive. To create a new primary partition on the USB flash drive, type create partition primary and then click ENTER . To select the partition that you just created, type select partition 1 , and then click ENTER. To format the partition, type f ormat fs=ntfs quick, and then click ENTER .

Photography Photography has always been a large part of my life. My first camera (when I was about seven years old) was a Kodak Brownie 127, a plastic box camera for eight 4x6 cm pictures on 127 film, a paper-backed roll film format. Then, I only shot black and white film. Through the years my cameras became more complex and expensive. But it was not until I signed up to a local photography course that I really appreciated the additional advantages of processing one’s own film and quickly built a darkroom and purchased the equipment required. This opened a whole new world of darkroom highlighting, shading, Solarization (the process of re-exposing photographic paper during the development process), and playing with chemicals to get certain effects. Nowadays, this can be done using digital software, but the experience is not the same as experimenting yourself. Whether you use a conventional film camera or have just purchased your first DSLR and want to learn the basics or are looking for simple ways to update your existing photography skills, the following tips might help build a strong foundation. However, photography is an art, so the learning never stops. So, what is Photography? ​ Photography is the art, application, and practice of creating durable images by recording light electronically using a digital sensor, or chemically using light-sensitive materials and chemicals, like photographic film. It is used in numerous fields of science, manufacturing, and business, and has more direct uses for art, film and video production, recreational purposes, hobby, and mass communication. Some cameras can also capture wavelengths of light invisible to the human eye, including UV, infrared, and radio. Having been a senior Shotokan karate instructor I quickly learned that to keep improving the best way is to practice often using varied techniques, make mistakes and be open to learning from others. Essential photography tips ​ 1. Hold your camera correctly - Sounds obvious, doesn’t it, but many photographers do not hold their camera correctly, which can cause camera shake that produces blurry images. Tripods are the best way to reduce camera shake, but in truth, how many people carry a tripod, unless they are shooting in low light situations or have learned the hard way? If not using a tripod it is important to hold the camera correctly to help to reduce unnecessary movement. ​ Most people will sooner or later develop their own way of holding the camera, but it should always be held with both hands. Grip the right side of the camera with your right hand and place your left hand beneath the lens to support the weight of the camera. ​ Also, the closer you keep the camera to your body, the more stable it will become, so keep it close to the body mass. Additional stability can be achieved by leaning up against a wall or crouch down on your knees, but if there is nothing to lean on, try adopting a wider stance. 2. Composition - understand the rule of thirds, fifths, or sixes Old artists deeply understood the composition rules. Most older photography books discuss the thirds, which is based on the idea that pictures are generally more interesting and well balanced when they are not centred. Imagining a grid placed over your images with two vertical lines and two horizontal lines that divide the picture into nine equal sections. ​ Rule of thirds is a photography guideline, dissecting the image into 9 parts, with two evenly spaced horizontal lines. ​ So, following the rule of thirds, rather than positioning your subject or the important elements of a scene at the centre of the photo, place them along one of the four lines, or at the points where the lines intersect. Many cameras even have a grid option you can turn on, which can be useful when composing images. ​ However, rules are made to be broken. Photography is about creativity and personal expression, so sometimes choose to break this rule and place the points of interest elsewhere in the photo. This is fine, but before breaking these rules, it is important to understand them and are in the habit of consciously thinking about composition, the points of interest, and where to place them. ​ These days, professionals, artists, illustrators, or photographers often use the rule of fifths or sixes for composition. Looking at the Dutch and Flemish painters of the sixteenth and seventeenth centuries who used fifths or sixes rules for grand naturalistic landscape and seascapes composition, to empathise dramatic a sky or ocean. 3. Eyes must always be in focus ​ When shooting portraits, the focusing area is small, so it is more important to get the image sharp. The eyes are an important facial feature, and they are often the first thing people look at, especially when it comes to close-ups photography and headshots. ​ So, the subject’s eyes should be the main point of focus. To get both eyes sharp, choose a single focus point and aim it at one of the eyes. Once the first eye is in focus, keep the shutter button pressed halfway down and move the camera to recompose the photo and include the second eye. 4. Consider the background ​ Normally, the background ought to be simple and as clutter-free as possible, so it does not pull the viewer’s attention from the main subject of the photograph. Muted colours and plain patterns often work well, no one wants viewers in being more interested in the colourful building or church tower in the background than your main subject unless a photographer wants to make a statement. ​ Fixing a distracting background can be as simple as moving the subject matter or changing an angle, but if that does not work, try to obscure it by using a wider aperture and getting in as close to the subject as possible. Whenever possible, keep the background neutral, especially if placing the subject off to one side of the photograph making the background more visible. 5. Play with perspective ​ The best way to up creativity levels is to experiment with perspective. Any scene will look remarkably changed when approached from a different angle, while, capturing your subject from above or below can change the feel of a photograph. ​ Of course, changing angles may not work for every photograph, but unless considered or tried how do you know what works. Experimentation is the key factor to help improve your photography. Make mistakes, try new things, and think out-of-the-box. When shooting small objects, animals, or children, get down to their level and view the world through their eyes. If shooting a portrait, consider standing on a bench and shoot your subject from above, or, have them stand on a bench and shoot up. 6. Shoot in RAW ​ RAW is a file format like jpeg, but unlike jpeg, it captures all the image data recorded by the camera’s sensor rather than compressing it. Shooting in RAW provides higher quality images but also allows for more control in post-processing. For instance, correcting underexposure problems or adjusting aspects like colour temperature, white balance, or contrast. ​ However, one negative aspect of shooting in RAW is that the files take up more space, so I advise using larger SD or Micro SD Cards. Furthermore, RAW photos need some sort of post-processing, so photo editing software is essential. 7. Understand the exposure triangle ​ While it can seem intimidating at first, the exposure triangle simply refers to the three most important elements of exposure, ISO, aperture, and shutter speed. When shooting in manual mode all three of these things need to be balanced to get sharp, well-lit photos. ​ ISO - controls the camera’s sensitivity to light. A low ISO setting means the camera will be less sensitive to light, while a higher ISO means it will be more sensitive to light. Conversely, the quality of the image will decrease as the ISO increases and you may see 'noise (grain)' on the image with a higher ISO. So, an ISO setting of 100 to 200 is usually ideal when shooting outdoors during the day, but when shooting in low light situations, such as indoors or at night, using a higher ISO of 400 to 800 or higher may be necessary. ​ Aperture - is the opening in your lens, it controls how much light gets through to the camera’s sensor as well as the depth of field. Depth of field refers to the area surrounding the focal point of the image which remains sharp. A wider aperture (indicated by a lower f-number) lets more light through, but it has a narrow depth of field. While a narrow aperture (indicated by a higher f-number) lets less light through but has a wider depth of field. A wide aperture is terrific when you want to isolate your subject, but when you want the whole scene to be in focus, such as with group shots, a narrow aperture is required. ​ Shutter speed - controls how long the shutter stays open when you take a picture. The longer the shutter stays open, the more light gets through to the camera’s sensor. A fast shutter speed is great for freezing action like a horse jumping a fence, while a longer shutter speed will blur motion. Long shutter speeds can give interesting effects, like flowing river water over rocks but require a tripod. 8. Use a narrow aperture for landscapes ​ Landscape photographs entail an atypical approach because everything in the foreground to the mountains in the background should be sharply in focus. So, when shooting a scene where everything needs to be fully in focus, select a narrow aperture rather than a wide one. ​ A larger f/ number means a narrower aperture, so aim towards f/22 or higher, depending on what the lens allows. Using Aperture Priority Mode (Av or A) will allow experimentation with different apertures without having to worry about adjusting the shutter speed each time. 9. Experiment using Aperture Priority and Shutter Priority Mode ​ Only using automatic mode will limit anyone’s photographic potential, so, experiment using Aperture Priority Mode (A or Av) and Shutter Priority Mode (S or Tv), as they are two valuable options that are available on most cameras. ​ Aperture Priority Mode allows the selection of the aperture and then the camera adjusts the shutter speed accordingly. So, when shooting an object and want to blur the background, select a wide aperture, and let the camera decide the shutter speed. ​ While, Shutter Priority Mode, allows the selection of the shutter speed, and the camera will select the correct aperture. So, for a crisp shot of a racing car speeding past, select a fast shutter speed (a high number, 2000 or higher) and let the camera choose the aperture. 10. Raise the ISO ​ Many photographers try to elude shooting in high ISO as it will lead to grainy-looking photos or ‘noise’. But, while using a higher ISO can lead to lower image quality, grain in some photographs can be beneficial. ​ If the shutter speed cannot be lowered due to motion blur, and a tripod is not an option, it is better to obtain a sharp photo with some noise than no photo at all, anyway, much of the noise can be removed during the post-processing. ​ Furthermore, camera technology has improved so much in recent years, so it is possible to produce great photographs with ISOs of 1600, 3200, 6400, or higher. ​ Either way, using a wider aperture can help to minimise noise when shooting at higher ISOs, and slightly overexposing your image can also help, as making light areas darker in post-processing will not increase noise, whereas making dark areas lighter will. ​ Bearing that in mind, always check the camera's settings before going on a shoot. Discovering that the whole shoot was shot at an ISO 1000 on a bright sunny day can be exasperating, especially if the photos were taken to document a special occasion or other events that cannot be recreated. ​ It is an easy mistake to make (Yes, I learned the hard way), so, to avoid unpleasant surprises, make a habit of checking and resetting your ISO settings before shooting anything. 11. Learn to use the white balance ​ White balance can help you capture colours more accurately. Different types of light have different characteristics, so not adjust the camera's white balance will result in the colours in your photography taking on a marginally blue, orange, or green hue or ‘temperature’. ​ Of course, white balance can be fixed in post-processing, but it can become tedious if you have hundreds of photographs that require small adjustments. Some of the standard white balance settings on a camera include Automatic White Balance, Daylight, Cloudy, Flash, Shade, Fluorescent, and Tungsten. ​ Each is symbolised by a different icon, so check the camera’s manual. Automatic white balance works okay in many situations, but it is best to change the setting according to the type of light shooting in. ​ When shooting indoors I use daylight bulbs for photography and videos, actually, all the bulbs in the house are daylight rated. 12. Flash can be overused or not adequate ​ Built-in camera flash at night or in low light can lead to some unpleasant effects, such as red eyes or harsh shadows. Generally, it is more advisable to better to increase the ISO and get noisier photos than to use the on-camera flash and risk ruining the shot altogether. ​ However, occasionally there may not be enough light, and if you do not have off-camera lighting, there is no other choice but to use the built-in flash. If in this situation there are a couple of things that can be done. First, find the flash settings in the camera’s menu, then reduce the brightness as much as possible. ​ Secondly, use a diffuser, parchment paper is a good option, secure it with tape. Or bounce the light off the ceiling by holding a reflector or white cardboard in front of it at an angle. ​ Nearly all hot-shoe flashguns come with diffusers. 13. Invest in a tripod or two ​ To get sharp photos in low light without raising the ISO, a tripod is an essential accessory. It also allows experimentation with long exposure photography, when the shutter is open for seconds or minutes at a time, this can produce amazing effects when photographing like the sea, rivers, or waterfalls. ​ However, when purchasing a tripod , there are several things to consider, such as weight, stability, height, and flexibility. ​ Weight is important because carrying a heavy tripod around is not fun, but it also needs to be stable enough to support the camera and the lenses. Tripod buying guide . 14. Be selective ​ An important factor to realise is that every photographer, no matter how experienced or talented, will get mediocre shots. However, the reason their portfolios are impressive is that they only display their best work; they do not bore you with the twenty other photos depicting a virtually identical scene. ​ So, if you want your work to stand out on Facebook, Instagram, website, or photo-sharing sites like Flickr or 500px, narrow it down to a couple of extremely good photos from each shoot. By showing the mediocre shots you obscure the three or four great shots obtained. 15. Learn by mistakes ​ Getting overexposed, blurry, grainy, or badly composed photos may be frustrating, but use them as a learning tool, analyse them, what did you do wrong, what do you do right. Keep notes of each shot and the associated factors, like lighting, flash or no flash, handheld or tripod, strong winds with an insubstantial tripod. ​ Most of the time there will be a simple solution such as changing the composition or using a faster shutter speed or changing the aperture. 16. Invest in decent photo editing software ​ This brings us back to shooting in RAW: When shooting in RAW, post-processing will become essential rather than an afterthought, so invest in some photo editing software that will allow basic editing tasks such as, cropping, adjusting exposure, altering white balance and contrast, and removing blemishes. ​ Most professional photographers use programs like Adobe Photoshop or Lightroom, but less pricey options are Photoshop Elements, Picasa, Paint Shop Pro or GIMP (Gimp is a free powerful open-source software). 17. learn to shoot sunrise or sunset ​ Lighting can make or break a photo, and the early morning and evening are widely thought to be the best times of day for taking photos. In photography, the hour just after the sun rises or before it sets is called the ‘golden hour’, because the sun is lower in the sky and the light is softer and warmer. ​ Whether shooting landscapes, portraits, or still life, using the early morning or evening light can give photos a serene feel with its warm glow and the long shadows it casts. 18. Bracketing ​ One of the most useful techniques in photography is called bracketing , in other words, taking multiple photos of the same subject with different camera settings. Normally, bracketing is about changing your exposure: one photo at the meter’s recommendation, plus one under and one over. But exposure is not the only variable at play here. Why Bracket Photos? ​ Bracketing means you capture a sequence of photos while changing your camera settings from shot to shot. This means you end up with two or more photos of the same scene, with only a couple of differences in each shot. ​ Exposure bracketing is the most common kind of bracketing in photography, will usually ending up with one photo that is too dark, one that is too bright, and one with a correct exposure. But bracketing the focus distance will resulting in one photo that is front-focused, another that is back-focused, and one that is accurate. ​ Some people consider bracketing takes up memory and wastes time. Especially if one knows what settings needed for an image, so, why bracket shots? There are two important reasons why bracketing is beneficial in photography.

HDD Error Management Hard Drive Error Management ​ A healthy primary becoming a RAW partition can be caused by several reasons, such as: ​ Virus infection Format failure Accidental OS shutdown Power outages ​ How to do RAW partition fix easily in Windows 7/8/10? There are a few ways you could choose from. ​ DISCLAIMER: The examples that I have illustrated are ones I employ to deal with hard drive problems. They might be dangerous to use for some systems. These procedures may also be ineffective. If you try them, you may cause damage or irreparable data loss. Because of this take great care. Therefore, I take no responsibility for anything you do based on my examples or the information that I have provided. ​ How to Fix: Internal or External HDDs that became RAW. A commonplace and bewildering problem with computers is the unexpected and mysterious disappearance of a hard drive (HHD) that has been working properly. It can be a horrendous experience to suddenly find that your data might be gone forevermore. I still get the stomach tightening when a message box reports that your HDD has given up the ghost. ​ It is easy to say, ‘ Don’t panic ’, but most inexperienced people will have that gut-wrenching moment when the hard drive is no longer usable. ​ If approached sensibly and carefully, the situation can usually be resolved, and the data saved. Below we will look at a few of the causes, fixes, and preventative measures for occurrences involving HDDs used with Windows XP and Windows Vista/7/8, Yes, I know they are old systems, but I know of a major computer store that still uses XP because of the cost and management implications of upgrading to MS Windows 10. ​ Error Messages Usual error messages associated with the inability to access an HDD. When attempting to access the drive in Windows you may see a message asking you to format the drive - ‘You need to format the disk in drive before you can use it, Do you want to format it?’ ​ DO NOT FORMAT THE DRIVE Another error that you may see when trying to access the drive in Windows from a program or the command line is - ‘ This volume does not contain a recognised file system. Please make sure that all required file system drivers are loaded, and that the volume is not corrupted. ’ ​ ​ ​ ​ ​ ​ ​ Attempting to run chkdsk with a RAW HDD to repair the problem will give the error – ‘chkdsk cannot be run on the drive’ The type of the file system is RAW. CHKDSK is not available for RAW drives.’ Before going on, you need to be aware of the risks involved. ​ If the problem with the drive is not a logical error but is a symptom of physical damage, the more you try to use or repair it, the worse the damage may become. ​ The drive should not be making strange clicking or beeping noises. If this occurs it indicates physical damage. ​ In these situations, I disconnect the drive from my windows machine and plug it into a purely Linux machine to repair or recover the data. Even so, this can make the situation worse. ​ If you wish to continue your own there are a couple of important rules to remember. If you do not have a dual boot system with Linux perhaps a friend does. ​ Do Not try to write anything to the raw DRIVE apart from trying to repair the Master Boot Record (MBR) and Boot Sector. Any other data transfer, deleting partitions, or attempting to format the drive can overwrite data on the drive. ​ If you have important data or photographs on the drive do not mess about it, take/send it to a professional for data retrieval. ​ Computer problems are erratic and not set in stone. So, try other ideas, search the web. Not every option will work so it is important to think laterally. ​ If the drive does not hold important data you can try to format it using the command line - I have had several successes, but also many failures. ​ If you do not need any of the data - use the 'Disk Clean' method below Open the Disk Management window and click on Disk Management in the left pane and make note of the disk in the middle pane of the disk that you want to clean or clean all (Fig: Be sure that you have the correct disk, check the number, mine is drive ‘T’ No. 4. You would not want to wipe clean the wrong disk. Press the Windows + C keys to open the search dialog, type command on the left side of your screen right-click the ‘ Command Prompt ’ tab and choose ‘ Run as Administrator ’ at the bottom of the page, and click the link. Once the Shell opens (Fig: 1) a line will display: C:\WINDOWS\system32\ Fig: 1 Type ‘ diskpart ’ (Fig: 2) and press ‘ Enter ’ Fig: 2 Beside DISKPART> type ‘ list disk ’ and press ‘ Enter ’ ​ You will see in (Fig: 3) that there are 6 disks listed 0 to 5, remember I am using disk 4. (Double, no triple check you have the correct disk before continuing) Fig: 3 Now the prompt (Fig: 4) displays ‘ Disk 4 is now the selected disk ’ ​ Beside DISKPART > type ‘ list disk ’ and press ‘ Enter ’ You will see in (Fig: 4) that I have 6 disks listed 0 to 5, remember I am using disk 4. (Double, no triple check you have the correct disk before continuing) ​ Beside DISKPART > type ‘clean’ and then press ‘ Enter ’ Fig: 4 Disk 4 will now be cleaned, once complete it will state ‘ DiskPart succeeded in cleaning the disk ’ (Fig: 5). Fig: 5 For a full clean, just type ‘ clean all ’ instead of ‘ clean ’ and press ‘ Enter ’ as before – a clean all will take many hours if you are using it on a large drive. ​ Go back to the Disk Management screen and format the drive, normally it will format fine using efat system, but I have had problems with some hard drives reverting back to RAW when trying to format them in NTSF .