how can I learn more about computers.

*this is a guide that was created from lecture videos and is used to help you gain an understanding of how can I learn more about computers.

RAM sticks and speed
To do anything on your PC, a program must be loaded into RAM. Capacity and speed are determined for RAM. “stick of RAM”

DRAM- every bit stored with a little capacitor and a little transistor.
SDRAM- 168 pin DIMM, synchronous to clock speed on motherboard. Lasted quite awhile and you will still see it today.
DDR SDRAM- 184 pin DIMM package, DDR has a single notch. Double data rate. Took motherboard speed and doubled it! Take motherboard speed and double that and that is your DDR speed, then take DDR speed and multiply by 8 to equal PC1600 or other number.
DDR2- 240 pin DIMM, notch in center. Doubled the motherboard speed, then you double it again, to get the PC speed you times it by 8, just like normal DDR.
DDR3- most common today, 240 pin DIMM, quadruples the bus. 100 mhz, multiply times 4 = 4, double that to DDR3 = 800 and then times it by 8 for PC speed, which is 6400 speed.

RAM Capacity
Install the same capacity of RAM onto that computer. RAM is also additive. Refer to your motherboard for more information about the capacity. Do not mix RAM sizes and speeds as it will cause instability.

Choosing a power supply
Efficiency- measured as percentage, a good power supply has north of 90% meanwhile a bad power supply is under 50%. Go with the best power supply at least around 82 to 85 percent.
Rails- 12, 5, 3.3 volts DC. Electrical circuitry that isolate different types of power outputs so one does not get sacrificed to the other.
Positive 12 volts is most important voltage.
Really good power supplies quote their efficiency at operating temperature or at wattage.
If you don’t have a two rail system, you may run into issues down the line.

Power protection
Spikes- more voltage then we are suppose to have
Sags/brownout- when you do not have enough voltage, sags are better than spikes
Surge suppressors- used to prevent spikes, smooths out spikes to no more than 120 volts. Buy an expensive one! Look for a UL rated power strip. And look for a reset button or a breaker.

UPS- surge suppressor with built in motorcycle battery. Measured in joules, or watts per second. APC makes good UPS products.

Understanding partitioning
Boot partition- takes part of hard drive so you can install boot stuff
Recovery partition- takes part of hard drive so you can have room for repair and recovery
Create a partition and then mount it. All drives have at least one partition.
Types of partitioning- MBR or GPT
MBR consists of bootloader and partition table, problem was it had a max of 4 partitions and was limited to two terabytes. The partition table includes where does it start, where does it end and what kind of partition? System partition are only accessed by the OS.
Boot loader- tiny bit of code, tells the system which partition to go to to find the OS, which is active partition.
Primary partitions- you can put an OS on it.
GPT- MBR replacement, Includes Protective MBR, Primary GPT Header, not limited to 4 partitions, has a backup copy of itself

Basic Partitioning
MBR Partitioning
Create a new partition- Plug in your hard drive -> disk management ->create new simple volume -> assign drive letter -> format partition
Deleting volumes is permanent.
Create 2 partitions- disk management ->simple volume -> specific volume, take half of volume, assign drive letter -> format partition -> simple volume to repeat process to create 2nd partitioning.
Create 4 partitions- in MBR, extended partition and logical volume is used to get past max 4 partition limitation, you can take an extended partition and make a logical drive

GPT Partitioning
GUID Partitioning Table, GUID is a 128 bits long that your OS uses to keep track of things. Users, printers, software, chipsets used assigned GUID’s.
REGEDIT will show you folders of GUID.
Create a new partition -> Convert to GPT disk with right click -> simple volume -> assign drive letter -> format partition
GPT does away with extended partitions. Has a maximum of 128 partitions! Use GPT over MBR.

Dynamic Disks
Predate GPT but came after MPR. Still used today.
To convert a drive from basic to dynamic- disk management -> right click to convert to dynamic disk
You can expand and shrink volumes with basic disks.
Spanning -> disk management -> right click on disk -> new spanned volume -> select 2 drives
Spanned volumes take 2 drives and act like one volume, it is risky, no fault tolerance.
Like RAID 0, spanned drives are not fault tolerant.
The only way to convert a dynamic disk back to basic is if you delete all the volumes.

File systems
Intermediary between the OS and storage media. Every file system uses an allocation table.
FAT File system- uses binary number system lined up to block, and the status, each sector/block stored 512 bytes. 66,536 entries is the most you can use on a block.
FAT couldn’t use a hard drive bigger than 32mb, used in 1970’s.
Microsoft came up with Clusters or file allocation unit. If hard drive was a certain size they would use groups of clusters and it was handled for you automatically.

Types of file systems
FAT- 16-bit file system – Max capacity 32MB partition
The original file system, no file permissions
FAT32- Uses 32 bit addressing, up to 2TB partition
Maximum file size is 4gb
Still popular on flash media, no file permission.
exFAT/FAT64- great for large flash memory, up to 128PB partition and file size

Ext3- older, Linux, 32tb, unix-style permissions
Ext4- Linux, vastly improved ext3, performance, data security, EB partitions
HFS+- unique to Apple, 8 EB partition, linux style permissions

NTFS- powerful and granular file permissions, used for Windows, popular today, data security, 256tb partitions

Storage spaces
Windows storage spaces- Control panel -> create pool, figure out what RAID you want. It came out with Windows 8. Doesn’t work on boot drive.
4 kinds of resiliency- Simple JBOD or one big hard drive, 2 way mirror, like a RAID 1 mirror, needed 2 drives, 3 way mirror is like RAID 6 and need minimum of 5 hard drives but can lose 2 drives before losing data, Parity is like RAID 5 and needs minimum of 3 drives.
Thin provisioning- virtualizes the pool and allows for other drives to be added easily
Storage spaces is flexible and does not care where your data storage is.

Configuring USB
Always install device driver first before you plug in the device
Computer management -> device manager -> USB controllers not for individual devices but for each USB go to Properties -> Advanced
Different controllers handle different versions of USB
Do not turn off the device drivers during system setup
Windows popups- “You’re running out of power or this device can work faster.”

Media sources
Optical media can get lost, get scratched and is slow.
ISO- block by block copy of optical media from ISO9660
Use tools to take optical media and scrap the data or download the ISO.
Making an ISO- place optical media in machine -> ISO recorder tool to create image from cd/dvd.
You can use ISO to make backups of optical media, put it on thumb drive, or install operating machines on virtual machines.
An ISO is an image of particular media.
Iso can be installed onto any block level media
Install ISO on thumb drive- plug in thumb drive -> Rufus by Akio tool takes an ISO and puts on media

Linux Operating System

Linux command line basics
All commands must be lowercase
Pwd shows your current working directory
Ls lists files and folders
Cd changes directory, similar to Windows

Vi text editor used in Linux
Ex. Vi bob to create text file named bob
Vi uses a mode based interface
i activates insert mode in vi so you can write text / esc takes you out of it
H- left, j- down, k- up, i- right
W will save the file, q will quit vi

Shutdown will shutdown the system
Sudo shutdown will shutdown the system

Working with folders and files in Linux
Cp is used for copying files in linux; linux uses /, Microsoft uses \
Cp * ../backup will copy documents, go up into 2 previous folders and will copy into backup folder
Mv works exactly like copy, except moves the folder
Rm deletes files, same structure as mv and cp
Rmdir will remove a directory/folder
Mkdir will create new folders
Dd copies disks and partitions, requires sudo when working with hard drives
Ex. Sudo dd if=/dev/sda of=/dev/sdb will create copy of sda hard drive to the sdb hard drive
Ex. Sudo dd if=/dev/sda1 of=-/backup.img will copy first partition and will copy to backup.img
Ex. Sudo dd if/dev/urandom of=/dev/sda bs=4k will wipe out the hard drive

Linux file permissions
3 groups of rwx, which are 3 different permissions. First is the creator/owner, second is for the group, third is for other and everybody else.
R- read, view contents
W- write, edit a file, add and delete files
X- execute, run a file, cd to a different directory
Chmod is used to change permissions, o= other, g=group, a=all
Ex. chmod o= RunMe will change permission for others on a file named RunMe
g=rx will mean that the group will give group only read and execute permissions
You can also change permissions with binary, Ex. 010 is -w-, 111 is rwx
You can type in the value of 4 for r, 2 for w and 1 for x, you can add them together to give permissions such as 6 will give read and write permissions.
Chown is used to change ownership, needs sudo
Ex. sudo chown root RunMe will change the owner of RunMe to root
Passwd is used to change passwords, needs sudo

Miscellaneous Linux Commands
Grep utility designed to search for text strings within text files
Ex. grep “error” filename, will search for error in a specific file
/var/log folder stores most of your systems logs
Ex. Grep -r “error” /var/log will search for the text error in your log files
ps shows running processes within your system
Ex. ps aux will show all of the processes for everybody on the system
A pipe redirects output from one command to another
Ex. ps aux | grep “evol”
Ifconfig gives info about your wired network connection and you need basic information about your system
Iwconfig will show more detail about your wireless connection then ifconfig
Apt-get is a package management system used on the debian system, such as raspberry pi
A package is a precompiled application, package management allows you to go into the command line and type in a command to find a specific application, find the repository with the package and install it.
Ex. sudo apt-get update will refresh the package cache
Ex. sudo apt-get upgrade will ensure all your packages are up to date
Ex. sudo apt-get install will fetch and install new packages
Ex. sudo apt-get remove uninstalls a package

Visit Lifehacker to learn more about how to get started with Linux.

Virtualization

Emulation is different as it uses software to imitate hardware while Virtualization uses a systems actual hardware. Virtualization saves power and consolidates hardware. Virtualization is also great for duplication and research for different systems.
Hypervisor- manages and runs the virtual machine, example is hyperV. You can have a hosted or type 2 hypervisor. You can also have a type 1 or bare-metal hypervisor which boots up a system.

Oracle VirtualBox is free- give it a name, type, versions -> memory size -> hard drive -> hard drive file type -> storage on physical hard drive -> file location and size. You need to install an operating system, through an ISO image or an optical media. You can change the virtual hardware. Snapshots store the current state of a virtual system.

IaaS
Somebody will set up and rent you a virtual infrastructure for you, such as AWS. AWS management console is an IaaS. EC2 -> Launch instance (virtual machine) -> select OS -> choose instance type -> configure instance details -> Tag instance -> configure security group. Administer through Remote Desktop to access the web server you created. Used to easily create a public website.

PaaS
PaaS is used to quickly get your software running live on the internet. Ex. Developers can create web applications easily. Heroku is a PaaS. You can have your code, upload it to Heroku or another PaaS and then you will receive a real URL to deploy the web application. Heroku on command line- heroku create appname -> load code with git push heroku master command -> heroku open command to see web app URL. Dyno is used to create more resources within Heroku.

SaaS
Instead of having a CD that you have to install, you buy a subscription, so you do not need optical media. Microsoft Office 365 is a SaaS. Dropbox is also a SaaS.

Cloud Ownership
AWS is a public cloud. A private cloud allows only you access. You can invite certain individuals within your community to access the cloud, which is a community cloud. A hybrid cloud uses both a public and private cloud.

Internet Options
Internet Options apply to the internet explorer browser
Access through Control Panel. General tab for homepage settings. Security tab is for the most part, obsolete, with Windows 10. The Privacy tab is for adjusting cookies and the pop-up blocker. Content tab is for controlling what can appear in the browser and also for autocomplete settings. Connection tab for internet connections. Program tab for adjusting external applications. Advanced tab for resetting internet explorer.

Proxy servers
A box between internet and server. You can manually adjust every internet application to use a proxy server. Google Chrome Settings -> show advanced settings -> network change proxy settings -> LAN settings -> Check, use a proxy server for your LAN and type in address and port number, typically port 80. Internet settings applet is used for setting up proxies. Malware can change proxy settings.

Troubleshooting Internet Connections
DNS problems- trying to get to a webpage and it doesn’t work. Try to ping something and if it doesn’t give you an IP address, then it is your DNS. Type ipconfig /all to find your DNS server, use nslookup to see if a particular IP address is good for your DNS. If it is good, check your cache by typing ipconfig /displaydns, and then you can flush by using the command ipconfig /flushdns. If your DNS is really dead, you can go into your internet connection and you can use a public DNS server such as 8.8.8.8, which is Google’s DNS.

Slow response time- watch out for your network utilization., go to task manager -> networking. Netstat command can allow you to see your processes and determine which ones to kill. Quality of Service is a router feature that is used to optimize network bandwidth for a certain computer over others in a network.

Installing local printers
Local printer- printer that connects directly to your local machine. You need print drivers. You can use the drivers that came with the printer, Windows drivers or you can download the latest driver from the manufacturer. Windows drivers update automatically and is an easy choice. Right click to get to printer preferences. Duplex means a printer can print on both sides of the paper. Right click to get printer properties for the configuration settings. Print a test page after to see.

Installing Network Printers
Own host on your network with its own IP address and NIC. It needs to be able to take commands from Linux, Microsoft, Apple etc.
Setup network printer- Run easy wireless setup with printer -> select wireless network -> setup wireless connection -> Access web interface on Internet with printer’s IP address -> adjust settings as necessary.. Wifi direct is an ad-hoc network.
SLP service location protocol port 427, used for netware os, hp jetdirect.
Universal plug-n-play is a standard service locator.
SNMP (Simple network management protocol) collects information and statistics from network devices, uses port 161 and 162. You can use SNMP to talk to devices and determine what problems that server has.
(Windows 10) Network Printer Installation- add printer -> find a printer by other options (autodirect or find printer by IP address) -> add a printer using a TCP/IP address -> type in printer’s IP address -> print test page.

Cloud Printing
Take a printer and place it on the cloud so anybody from any device can print from it.
Google Cloud Print- setup through printers web services -> register google cloud print -> click on url to google cloud printing -> login to gmail to register and add a cloud ready printer

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