1. CS101
Storage Information

2. Storage
The zeros and ones in the input devices, output devices and process devices are in electronic form and are lost when the computer is turned off.
To preserve the zeros and ones when the computer is turned off they must be sent to storage devices

3. What type of storage devices are there?
Older Storage
Magnetic Devices =
How stores information = As magnetic metal particles with a north an south pole
Optical Devices =
How stores information = Surface reflects back laser or does not
Newer Storage
Solid State Devices =
How stores information = Traps electrons
Hybrid Storage
Combines Solid State and Magnetic
Cheaper
Cloud Storage =
Not stored on your device.

4. Bits to Bytes Computers store information in byte size chunks
A zero or a one = bit
8 Bits = 1 Byte
1024 Bytes = Kilobyte
1024 Kilobytes = Megabyte (1,048,576 Bytes)
1024 Megabytes = Gigabyte (1,073,741,824 Bytes)
1024 Gigabytes = Terabyte (1,099,511,627,776 Bytes)
Etc
Keeps going by a factor of 1024
1024 because computer is a base 2 device

5. What type of file is what size?
What type of files would be kilobyte size?
Text files, HTML files, small Word documents, Spreadsheet, etc
What type of files would be megabyte size?
Applications (Word, PowerPoint, Firefox)
MP3’s, Photos, YouTube videos, etc
What type of files would be gigabyte size?
Full length movies at DVD quality, Collections of files (Office 2016),

6. How big is it?
How do I know how many bytes a file is taking up on a disk?
Windows = Right click on the file icon and select “Properties”
Macintosh = Right click on the file icon and select “Get Info”
How do I know how many bytes fit on a disk and how much of the disk is currently being used?
Windows = Right click on the disk icon and select “Properties”
Macintosh = Right click on the disk icon and select “Get Info”

7. How much can a storage device hold?
Kilobyte storage devices
None. To small to be of use with today's computers.
Megabyte storage devices
Floppy Disk (1.3 Megabytes)
Zip Disk (100 to 750 Megabytes)
CD (700 Megabytes)
Gigabyte storage devices
DVD (4.7 Gigabytes to 8.5 Gigabytes)
Blu-ray (25 Gigabytes to 50 Gigabytes)
Small Hard Drives (Magnetic and Solid State)
Small Solid State (Flash Drive, SD Cards, Hard Drive, etc.)
Terabyte storage devices
Magnetic Hard Disk (Multiple Terabytes)
Solid State Hard Disk (Multiple Terabytes)

8. Converting Measurements
To convert a smaller unit to a larger unit divide by 1024 for each level
To convert a larger unit to a smaller unit multiply by 1024 for each level

9. Conversion Practice
You can use the conversion calculator on the following website for practice:

10. Quick and dirty conversion
In the real world a quick conversion by 1000 will give you enough information
To convert a smaller unit to a larger unit divide by 1000 (or just move the decimal point 3 to the left)
To convert a larger unit to a smaller unit multiply by 1000 for each level (or just move the decimal point 3 to the right)

11. How do files get stored on disks
First the disk has to be prepared for use.
The disk needs to be formatted
First it is low level formatted
Second it is high level formatted
Formatted= Initialized

12. What happens when a disk is high level formatted (or initialized)?
High level formatting is usually done by OS or utility program and three main things are accomplished
1) The disk is divided up into clusters
Blocks are combined into clusters
For example 1 clusters= 4 Blocks
2) A Boot Sector is created in the first cluster of the disk
Tells the start up directions where to find the operating system at startup.
3) Then a file system is created on the disk
A file system keeps track of where files are stored on disk
Files are recorded as being in directories on the disk
We call the directories we make folders
Windows has two types of file systems
1 FAT = File Allocation Table
Older = Less secure and limited disk and file sizes
2 NTFS = NT File System
Newer = More secure and allows larger disks and files
Mac uses HFS+ (Mac OS Journaled)

13. How do you do a high level format?
In Windows:
Right Click Start > Disk Management
In Macintosh OS:
Open Disk Utility program
Select disk icon on left side of window
Select type of format
Select Erase tab and click on Erase

14. Neat formatting trick Break disk into partitions
Partition = Have one physical hard drive act as two or more hard drives.

15. What should I do if a sell my computer, or storage device?
To secure a storage device you need to randomly rewrite the data in all the blocks on the device
Format the device so that it does a random write to all clusters on disk.