memory, information
Random Access Memory (Ram)
Random-access memory is a kind of data storage for computers. Often known as the acronym RAM or basically memory, random-access memory details the speed in which data that are stored can be accessed at random. This means that the strength of the RAM determines, at random, how fast a piece of data can be pulled & returned. Regardless of where the data is on a drive or whether it is at all related to any earlier bit of data is irrelevant; RAM pulls it back at a constant time.
AM differs tremendous from other types of storage devices such as optical discs. These depend on the consistent movement of the medium in which information has been recorded. For example, a DVD player needs to have the DVD within to read the information. The downside to this is that it takes longer than an information transfer, but more importantly, based on where the information is physically in relation to the earlier minuscule bit of information determines the speed in which it's recovered. Because of this, RAM is faster at obtaining information than optical or magnetic discs. Their use, though, is in the fact that the information doesn't must be stored on the actual drive.
Types of RAM
- SRAM: Static random access memory has anywhere from four to six transistors for each memory cell. Because it doesn't have a capacitor for each cell, its primary use is for caching.
- DRAM: Dynamic random access memory gets its name because it consistently needs to be refreshed. It has memory cells that have a transistor and capacitor pair.
- FPM DRAM: This is known as fast page mode DRAM which is the original type. For each process – 0 or 1 – it goes from column to column and row to row to find the data. This slow speed allows for a max of 176 MBps.
- EDO DRAM: Extended data-out DRAM goes faster than its predecessor because it doesn't wait for the first bit of data to be found before it begins finding the second bit. This means it has a max transfer rate of 264 MBps.
- SDRAM: Synchronous DRAM is the most common used RAM in today's computers. Because it understands the principle that most CPU will have the data in sequence, it stays on one row containing a needed bit and then checks each column. This increases the transfer speed up to 528 MBps.
There are faster types of RAM, but the main point is that speed is based on how the RAM finds information. Therefore, when there is more RAM in a pc, it suggests that information can be found at a great speed which begs the final query: how much RAM do I require? The answer to that is simple. What are you going to do together with your machine? Most people suggest getting more if it is feasible & since upgrading RAM is usually cheap, getting more should not be looked down on. A faster machine means things are done more efficiently.
Read only Memory (Rom)
Because information is fully incorporated at the ROM chip's manufacture, information stored can neither be erased nor replaced. This means permanent & secure information storage. However, if a mistake is made in manufacture, a ROM chip becomes unusable. The costliest stage of ROM manufacture, therefore, is generating the template. If a template is obtainable, duplicating the ROM chip is very easy & affordable.
Read-Only Memory or ROM is an integrated-circuit memory chip that contains configuration information. ROM is often called firmware because its programming is fully embedded in to the ROM chip. As such, ROM is a hardware & program in one.
A ROM chip is also non volatile so information stored in it isn't lost when power is turned off.
RAM versus ROM
Both RAM plus ROM provide the user random access to stored information. However, RAM provides only short-term memory since information stored in RAM is lost when power is turned off. ROM, on the other hand, provides long-term storage since information is permanently etched in to the ROM chip.
One other difference between the two is that RAM's information can often plus speedily be altered plus changed at will. ROM cannot be reconfigured at all.
ROM Chip Manufacture
The ROM chip has a matrix of columns and rows. The point of intersection between the column and the row is called a cell. Each cell will have a value of either 1 or 0. The manufacturer of the ROM chip has to select each cell's value before the ROM manufacture ensues.
After the program has been designed, the ROM chip can now be made. At each cell where the worth ought to be 1, a diode is placed to connect column to row. At each cell where the worth ought to be 0, no diode is placed.
The ROM Chip's Diode
The diode has a maximum voltage requirement, what is often called the forward breakover, which needs to be surpassed before the diode will transfer the charge from the column to the row of the cell. The usual ROM diode forward breakover voltage is around 0.6 volts.
The diode is the cell's electronic check valve. Its main function in the ROM chip is to control & direct the flow of electrical current in cells. Specifically, it transfers the electrical current from column to row.
The ROM activates cells by sending through voltage that is over the cells' diode forward breakover. The charge that is directed through the column gets passed on by the diode to the appropriate grounded row. Since charge is successfully transmitted from column to row, the cell where a diode is present has a value of 1.
In the ROM circuit, passing a charge through the column won't affect the cells whose values are supposed to be 0. In any cell, this charge cannot be passed from column to row if there is no diode to facilitate the transfer. Therefore, once a cell's value has been determined to be 0, it will permanently be 0 .
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