File Organization and Protection
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Transcript of File Organization and Protection
FILE ORGANIZATION AND PROTECTIONTopic 5
CONTENT Files Hard Drives Viruses Optimize Computer System
FILES A file in a computer system is a sequence of
bits stored as a single unit Files are stored on a optical disk, magnetic disk,
or electronic storage (Flash drive)
FILES My system
Hard drive is partitioned into 6 sections Three sections are in Linux; not seen by Windows Two sections are C: and D: One section is boot drive (very small)
Windows remember things by putting small files here when computer boots
DVD-Read/Write Drive Removable Drive, Flash Drive
Windows 7 – color codes Red means drive has less than 10% of free space
FILES
FILES Flash drive, hard drive, DVD – CD ROM drives
Tree-like file structure Similar to a filing cabinet Navigate through the levels of your file structure Make folders to store files logically
Windows normally installed on C drive
Linux operating system Bootable from DVD or CD Bootable from a flash drive
FILES
FILES Note – my drive is complicated Windows folder – Windows operating system Program folder – Where software programs
are stored Note – I have two because I have a 64-bit
processor and 64-bit Windows 7 Program folder (x86) means 32-bit programs Program folder means 64-bit programs
User folder - stores user data like desktop, My documents, etc.
HARD DRIVES Important drive for storage and retrieval of large
amount of data Data is stored sequentially on magnetic disks Disk is called a platter A read/write head passes over the disk on an arm
Hard drives have different speeds 5,400 rotations per minute (RPMs) 7,200 RPMs Faster speed allows data to be stored or retrieved
faster Note – new hard drives are solid state
Similar to a flash drive No mechanical moving parts More expensive with smaller capacities
HARD DRIVES
HARD DRIVES Files should be stored sequentially on drive Fragmentation - Usually Windows put file
pieces in different spots File segments are not in sequence Takes longer to retrieve files, especially if drive is
over 10% fragmented Hard drive works harder Slows system down, especially for laptops CPU waits longer for stored or retrieved data
HARD DRIVES Windows has a disk defragmenter
Usually slow; completely reorganizes drive No pretty pictures
I used Auslogics Disk Defrag Free disk defrag utility Gives picture of drive Organizes files very quickly
HARD DRIVES
HARD DRIVES
HARD DRIVES Hard drives can fail
Usually after three or more years Hard drive is dropped to the floor Hard drive makes squeaky noises before it fails
Data should be backed up External hard drives are cheap Online storage
Store files at a website; retrievable from anywhere in the world as long as you have an internet connection
Examples Flipdrive Supersync Elephant drive
HARD DRIVES Windows and Linux
When you delete files, the operating system leaves the data there
It only changes the file allocation table A table keeps track where the pieces of a file are located A deletion tells the computer that new places are free for
new data and files
These files are easily recovered Other time, large files like music and movies will be
destroyed as new files are written over them Small files like documents, emails, and pictures can
survive for awhile If you edited a Word document 20 times, those 20 copies
may still be on the drive
HARD DRIVES If you have sensitive data on your drive,
never throw your computer or hard drive away. Remove the drive and keep it Physically destroy the hard drive Use a special program to format the drive
Changes all information to ones or zeros Quick format does not change the information
It only changes the file allocation table
Special programs exist that recover data Recuva – a free and excellent program
HARD DRIVES File compression
Some files are large Use compression to reduce file size
Not so important for hard drives Hard drives have large capacities and are cheap
Important for email Limited in attachments for emails
Common programs Built in Windows XP, Vista, and 7 Winzip 7-zip
HARD DRIVES Windows (and Linux) fill the drive with junk
Temporary programs Installation files Internet files and history
Pictures, websites, and content Restore files
Over time, this junk can take up giga bytes of hard drive space away Periodically clean this
CCleaner – free cleaner
HARD DRIVES
HARD DRIVES Registry Cleaner – a program that cleans a
computer’s registry Registry – unique to Windows
A hierarchical database for the Windows Operating System
Configuration settings Software options Tracks the performance of the operating system
Do not manually edit the registry!
Do not manually edit the registry!
HARD DRIVES If the registry is damaged or corrupted,
Windows may not work Either replace registry with a backup Or re-install your Windows Operating System
To change or edit registry is type regedit on command line
Instructor: Uses a registry cleaner to remove unwanted
entries Improves speed for a laptop Some do not recommend this!
I used Eusing
HARD DRIVES
VIRUSES
Virus – malicious code Create annoyances, like
dancing icons on desktop Destroy system files and
information Transmission
Infected media like flash drive, etc.
Email attachment Install unknown program
from internet Visiting malicious websites
Virus Infected Computer
VIRUSES Other problems from malicious code
Worms – malicious code that replicates itself through a network or internet Worms take advantage of security flaws in a computer User does not have to do anything Origin of spam emails, etc.
Rootkit – dangerous type of virus Root is the main system directory in Unix (or Linux) Rootkit means a virus has penetrated the system files
and has authority to change any system setting Malware – steal passwords, credit card information,
etc. Very difficult to detect and eliminate
VIRUSES Spyware – program tries to collect
information Keylogger – program that reads characters typed
on a keyboard Passwords, etc.
Malware Usually does not try to propagate itself
Not like a virus or worm Usually user is tricked to download or installing a
program
VIRUSES Adware – advertising programs keep popping
up in new windows
Once a computer is infected, a virus or worm may open a door for more viruses and worms One virus grows into ten or more very quickly
VIRUSES How do you know your are infected?
Computer is slower Very long boot time Files mysterious disappears Webpages keep opening up Advertising to remove viruses, worms, etc.
This company may have put it there Programs act strangely or crash frequently Anti-virus program is disabled Worse case – destroys the operating sytem
VIRUSES Virus Protection Antivirus Programs
Program scans memory, Windows registry, and file system for viruses
Takes up resources, especially for a laptop Scans emails for threats Usually do not scan for Spyware or Rootkits
Usually more programs for these
VIRUSES Antivirus Programs
Bitdefender 1 Kaspersky 2 Webroot 3 Norton 4 ESET Nod32 5 AVG Antivirus 6
VIRUSES Antivirus programs are not free
Computer files need to be continually scanned Antivirus needs to be continually updated
Creators continually create new viruses Ignoring updates can jeopardize system
Antivirus is normally a subscription You pay for a license per year Usually one license for one computer Prices range from $30 to $100
VIRUSES Kaspersky Antivirus
Some say it is the best It made my system sluggish
AVG Antivirus Has a free version Does not hog up system resources Very basic protection
VIRUSES
Firewall – a program (or hardware) that monitors data flow between a computer and a network or internet
Firewall blocks unauthorized programs
Comes with Windows Operating System
Firewall Firewall for a Network
VIRUSES Windows Firewall
Go to Control Panel Firewall is its own option
Antivirus programs may also provide a firewall Usually an upgrade Usually adds to the cost
VIRUSES
VIRUSES Antivirus is only partial protections Rootkit scanners; some are free
Sophos Anti-Rootkit GMER RootRepeal Dr Web Cure it
VIRUSES Spyware and Malware (not rootkits)
Spybot (free program) www.safer-networking.org Immunization – protects internet explorer and Firefox
from bad websites Tea timer – prevents changes to msconfig.exe
MSConfig is system configuration Type msconfig in command window Tells which programs to load when system is booted Popular place for viruses
VIRUSES Windows Defender
Free spyware program for Windows Requires Genuine Windows Another way for Microsoft to check if operating
system has a proper license Type winver in command window for this
information
OPTIMIZE OPERATING SYSTEM Review
Use a cleaner to remove temporary files Use registry cleaner (potentially dangerous) Use disk defrag to defragment a hard drive
Important for laptops Use msconfig to prevent certain programs from
loading Periodically run antivirus, rootkit scanners, and
spyware scanners Keep Windows and Programs updated
Patches security problems Usually takes space and makes programs slower