Memory

Last week we learned about how external hard drives can help preserve memory on a computer--but what exactly is memory and how can you tell how much you have available? Additionally, when buying a computer or digital device how do you you know if you're buying something with enough memory?

Webopedia defines memory as this:

"Internal storage areas in the computer. The term memory identifies data storage that comes in the form of chips, and the word storage is used for memory that exists on tapes or disks. Moreover, the term memory is usually used as a shorthand for physical memory, which refers to the actual chips capable of holding data. Some computers also use virtual memory, which expands physical memory onto a hard disk.
Every computer comes with a certain amount of physical memory, usually referred to as main memory or RAM. You can think of main memory as an array of boxes, each of which can hold a single byte of information. A computer that has 1 megabyte of memory, therefore, can hold about 1 million bytes (or characters) of information.
There are several different types of memory:

RAM (random-access memory): This is the same as main memory. When used by itself, the term RAM refers to read and write memory; that is, you can both write data into RAM and read data from RAM. This is in contrast to ROM, which permits you only to read data. Most RAM is volatile, which means that it requires a steady flow of electricity to maintain its contents. As soon as the power is turned off, whatever data was in RAM is lost.

ROM (read-only memory): Computers almost always contain a small amount of read-only memory that holds instructions for starting up the computer. Unlike RAM, ROM cannot be written to.

PROM (programmable read-only memory): A PROM is a memory chip on which you can store a program. But once the PROM has been used, you cannot wipe it clean and use it to store something else. Like ROMs, PROMs are non-volatile.

EPROM (erasable programmable read-only memory): An EPROM is a special type of PROM that can be erased by exposing it to ultraviolet light.

EEPROM (electrically erasable programmable read-only memory): An EEPROM is a special type of PROM that can be erased by exposing it to an electrical charge."

(http://www.webopedia.com/TERM/M/memory.html)

They mention "bytes." Bytes are the unit of measurement for memory.

1 bit = smallest amount of memory
8 bits = 1 byte (B)
1,000 bytes (B) = 1 kilobyte (KB)
1,000 kilobytes (KB) = 1 megabyte (MB)
1,000 megabytes (MB) = 1 gigabyte (GB)
1,000 gigabytes (GB) = 1 terabyte (TB)

(a more extensive chart and explanation can be found at http://www.whatsabyte.com/ )

Currently, electronics are sold with a number of GB or smaller. Hard drives and computers seem to be the only things sold in TB. However, as our software and technology grows and demands more memory--devices will need to be sold with more memory. This is why computers made in the 90's (for example) cannot handle the same tasks that computers today handle with ease.

So let's put this into context:
iPhone comes in 8GB, 16GB or 32GB

iPad comes in 16GB, 32GB, or 64GB

Laptops are now sold with 250 - 320GB

Desktop computers are now sold with 640GB - 1TB

Digital cameras use memory cards with 2GB - 16GB or more

Assignment
For today's assignment we are going to do a scavenger hunt to help us understand how much memory is worth.

1. Find three pictures and figure out how big they are.
(Hint: if you search google images google will tell you how big the picture is. If you search on the computer click on the file and the size of the file will show up at the bottom of the window)

2. Find out how much memory an EMPTY folder uses.
(Hint: open any folder on the computer, right click, create new folder, click on the folder and at the bottom of the menu it will tell you how big it is)

3. Find three mp3s and figure out how much memory they use.
(Hint: search an mp3 download website. The size is usually listed)

4. Find out how much memory on your computer is used and how much memory you have left.
(Hint: open desktop folder click on my computer icon, stats will show on the side or the bottom)

Good at math?
Try and figure out how many pictures or mp3s you could download to fill up the space available on your computer :)

Question Review
1. How many bits are in a byte?
A. 6
B. 8
C. 10
D. They're the same thing just spelled different.

2. Which is bigger 1,000 KB or 1 MB?
A. KB
B. MB
C. They're equal.

3. Which is bigger 1,000 MB or 1 TB?
A. MB
B. TB
C. They're equal.

4. How many megabytes (MB) are in a gigabyte (GB)?
A. 1
B. 10
C. 100
D. 1,000