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There are discs, one on top of the other spaced a few millimeters apart. These discs are called platters. Polished to a high mirror shine and incredibly smooth they can hold vast amounts of data.The ACTUATOR ARM writes and reads data onto the disc. It stretches out over the platter and moves over it from center to edge reading and writing data to the platter through its tiny heads which hover just over the platter.
Hard drives use magnetism to store information just like on old cassette tapes. Copper heads are used as they are easy to magnetize and demagnetize using electricity.
When you save a file, the “write” head on the arm writes the data onto the platter as it spins. (Often around 4,000 RPM.) However, it doesn’t just go anywhere as the computer must be able to locate the file later. It also must not interfere or indeed delete any other information already on the drive. For this reason, platters are separated into different sectors and tracks. The tracks are the long circular divisions highlighted here in yellow. They are like “˜ Tracks” on music CD. Then we have the different sectors which are small sections of tracks. There are thousands of these from center to edge of the platter. One is highlighted blue in the picture.
In Operation When you open a file, program or really anything on your PC, the hard drive must find it. So let’s say that you open an image. The CPU will tell the hard drive what you’re looking for. The hard drive will spin extremely fast and it will find the image in a nano-second (or a fraction of a nano-second). It will then “read” the image and send it to the CPU (central processing unit – a.k.a. The time it takes to do this is called the “read time.” Then the CPU takes over and sends the image on its way to your screen.
Let’s say you edited the image. Those changes must be saved. When you click “Save”, all of that information is sent to the CPU, which sorts it (processes it), and sends it to the hard drive for storage. The hard drive will spin up and the arm will use its “write” heads to overwrite the previous image with the new one. Job done.
How does a flash drive write? USB or flash drives use flash memory. It is a solid state storage device, meaning there are no moving parts -- everything is electronic instead of mechanical. Here are a few examples of flash memory: Your computer's BIOS chip (code that runs the computer) Camera cards (all types of camera storage devices) PCMCIA Type I and Type II memory cards (used as solid-state disks in laptops) Memory cards for video game consoles
Flash drives write data using Electrically Erasable Programmable Read-Only Memory (EEPROM) storage protocol, which is notable for its rapid data transfers, and is also used in other data storage devices. However, the way flash drives use the EEPROM is a little different. In flash drives, the EEPROM can be electrically programmed and erased using field electron emission, during a process known as "tunneling.“
From here…. “Tunneling” and how exactly the transistors “open” and “close” gets very technical…… You are welcome to find out more about eeprom, flash drive storage, and tunneling on your own… Just know that flash drives and hard drives read and write differently
Remember from yesterday, the hard drive (also the DVD / CD drives) had to have a gray cable connecting it to the logic board and also power cables connecting it to the power supply for power. The gray cables are IDE cables (Integrated Drive Electronics). Older technology was SCSI, old technology is IDE, now there are SATA and ATA cabling… What you need to know is that the upgrades are for faster, better data transfer between the processor and the drives.
RAM – Random Access Memory A memory chip is an integrated circuit made of millions of transistors and capacitors. In the most common form of computer memory, dynamic random access memory (DRAM), a transistor and a capacitor are paired to create a memory cell, which represents a single bit of data. The capacitor holds the bit of information -- a 0 or a 1. (more about 1s and 0s later)
Random Access Memory (RAM) is the place in a computer where the operating system, application programs, and data in current use are kept so that they can be quickly reached by the computer's processor. RAM or DRAM (which is used more and more today) is much faster to read from and write to than the other kinds of storage in a computer, the hard disk, floppy disk, and CD-ROM. However, the data in RAM stays there only as long as your computer is running. It relies on ELECTRICIY. When you turn the computer off, RAM loses its data. When you turn your computer on again, your operating system and other files are once again loaded into RAM, usually from your hard disk .RAM can be compared to a person's short-term memory and the hard disk to the long-term memory. The short-term memory focuses on work at hand, but can only keep so many facts in view at one time. If short-term memory fills up, your brain sometimes is able to refresh it from facts stored in long-term memory. A computer also works this way. If RAM fills up, the processor needs to continually go to the hard disk to overlay old data in RAM with new, slowing down the computer's operation. Unlike the hard disk which can become completely full of data, RAM never runs out of memory.
A 0 or a 1 is how the computer “understands” information. A single 1 or a single 0 is called a BIT. This is a binary number system. BIT is short of Binary digIT. Let’s count to ten…. 1…2…3…4…5…6…7…8…9…10… But how does the computer “count” to ten?
0 = 0 1 = 1 2 = 10 3 = 11 4 = 100 5 = 101 6 = 110 7 = 111 8 = 1000 9 = 1001 10 = 1010 Because it only processes 1s and 0s. …….8 BITS together = 1 byte. So when your hard drive is “writing” it is just writing 1s and 0s!
You all have heard of a byte? Maybe a kilobyte? How about a megabyte? A gigabyte? A terabyte? A byte = 8 bits A kilobyte = 1024 bytes A megabyte = 1024 kilobytes A gigabyte = 1024 megabytes Get the idea?
Websites: www.howstuffworks.com/ www.makeuseof.com/.../technology-explained-how-does-a-hard-drive-w... www.tomshardware.com
