# Discovering Our Computer

It is the first year we are studying Computer Science at school. In this first term we have been studying the physical parts of our computer and installing an operating system in a pendrive, in order to be used in a computer.

# 1.Binary-Decimal Numbers

The process to change from Binary to Decimal and viceversa does not follow the same steps.

• From Decimal Number to Binary: We have to divide the decimal number by 2 until we can not continue. Then, we take the quotient and the remainders from the bottom to the top.
• From Binary to Decimal Number: We need to write the number upside down. Then we multiply each of the numbers by 2 to the power of a number depending on the position starting from 2 to the power of 0. At the end, we  add all the numbers and we obtain the decimal number.

• If you want to check if you did the process well, click on this link. It is a Decimal-Binary converter.

Decimal/Binary Converter

# 2. Hardware:

The hardware is the set of physical components of a computer. The main parts of hardware are:

• Motherboard: It is the principal element of the computer. It is formed by many printed circuits, which you can see behind the board, a series of slots, ports, and the most important part of the computer: the CPU (Central Processing Unit).
• CPU:  it is home to the microprocessor (it can be 1 or more), which processes raw data and transforms it into information.
• Slots: they are grooves in the board to enter memory cards, such as RAM and ROM.
• Ports: they are used to connect other devices to the computer, like the input devices (those that are used to input data/ e.g. mouse, keyboard, scanner) and the output devices (those that process information from the computer to execute the commands/ e.g. printer, speakers, screen)
• Storage devices: these are input and output devices used to hold information and to store backups of programs and data. The most important storage devices are:
• Optical drives: CDs (735MB), DVDs (8,5GB), HDDVDs, BDs (Blu-Ray Disks).
• Semiconductor drives: Pen drives (8-256GB), Flash Memory Card (32GB), Solid State Drives (32GB-2TB)
• Magnetic drives: Floppy Disk Drives (FDD), ZIP, JAZ, Magnetic Tape Drives (0.5GB-154TB), Hard Disks (40GB-3TB).
• Hard Disk Drives (HDD) are the most important storage devices, because all computers have one. To discover how an HDD works, go to the next section.
• HDD: the hard disk is a closed box in which we can find a set of disks which store data, and heads which read and write data on them.  Each of the disks is divided in concentric circles called cylinders, and in many radii called sectors. The combination of these two divisions is named disk sector.
• In the CHS method each disk sector can store 512 B.
• In the LBA method, the disk sectors are divided into logical blocks, each of them been able to store 512B, in order to allow to store much more data than in the CHS method.
• How to calculate the space of our HDD:

# 3.Software:

Software is the programs we need to run our hardware. It can be either systems software or application software. The most important part of the system software is the operating system that controls the hardware and runs the applications software, and this data is located in the logical part of the HDD.

• How to create a Live Pendrive:
• A live pendrive is a pendrive used to boot an operating system in a computer without installing it. To do that, we have created a multiboot pendrive in order to be able to install more than one operating system.In our case it is Ubuntu, but you can install another Operating System such as Hiren’s Boot CD. Click on this video to know how to create your live pendrive:
• If you cannot watch the video or you have problems with it,here are the steps to do it and some problems you might have with their solution.
1. First of all we need to download the ISO image, which is the Operating System we are going to install. Depending on how old or new your computer is, you will need to download the 64-bit version or the 32-bit version. (To know your computer version go to  “Start-up screen/ Control Panel/ System and Security/ System”). Go to Ubuntu webpage and click on “Download”to download the operating system.
2. After downloading Ubuntu, we should check with an MD5 file if the ISO image is corrupted. To do that, we have to download a program called MD5-summer. You can find your MD5 file for Ubuntu 14.04.3 in  http://nl.archive.ubuntu.com/ubuntu-cdimages/14.04.1/release/MD5SUMS.  When you open MD5 summer you will have to select the ISO image and click on “OK”. At the right you will see a long code made of numbers and letters, you will need to chech if that code is the same as the code from the ubuntu webpage.
3. To make our pendrive multiboot, we have used YUMI. Download it here http://www.pendrivelinux.com/yumi-multiboot-usb-creator/  . Open the program, click on showing all devices, select the pendrive you want to make multiboot. Next, select the ISO image you want to install, browse it and finally select at least 200 MB to allow to make changes.
4. After creating our live pendrive, we switch off our PC. Then we need to switch the computer on while we press the “F” command (not all the computers have the same command) to open the “boot menu“(Very Important!!), in our computer is F11. Find the name of your pendrive and click “enter”.Next, click on Linux distributions and then select ubuntu. Immediately your new operating system will be running.

### Enjoy It!!

This term we have both studied theory about computers and done practical classes, such as the live pendrive and creating this blog. In  our opinion it is very important to study theory about hardware and software to then be able to understand how our computers works and to use them in a better way.

We recommend you to have at least one multiboot pendrive to be able to use more operating systems than the usual ones. We know it is a long process but is easy if you know how to do it. It took us about 15 minutes to do it. Creating the multiboot pendrive is a really easy process, but it is hard the first time to understand what it is and how it works. Apart from Ubuntu, we recommend you to download and burn another ISO image called Hiren´s Boot CD. It is very useful to recover your computer in very little time in case it is scratched.