Find the History and Latest Technologies Between These Two Memories

8/3/2019 Find the History and Latest Technologies Between These Two Memories

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Find the history and latest technologies between these two memories.

1) ROM

2) RAM

INTRODUCTION

The latest computer systems are digital system. The major advantage of digital over

analog is the ability to easily store large quantities of digital information and data for

short or long periods. This memory capability makes digital system so versatile and

adaptable in many situations. Where do we store our information or programs in a

computer system? Your answer is probably hard disk, floppy disk, or CDROM. Correct,

these are the secondary memory. There are two categories of memory in a computer

system, i.e. primary and secondary memory. The system memory is the place where

the computer holds current programs and data that are in use. There are various levels

of computer memory, including ROM, RAM, cache, page and graphics, each with

specific objectives for system operation. This section focuses on the role of computer

memory, and the technology behind it. Primary memory is used as the internal memory

of a computer, which is in constant communication with the process of a computer

system.Any program or data used by the program reside in the internel memory while

the computer is working on that program.RAM and ROM ( to be define shortly) make up

internel memory. Primary memory is also called internal memory, main memory,working

memory, and semiconductive memory.RAM and ROM are semiconductor chips that

provide fast operation.Primary (semiconductor) memory provides smaller capacity

limited by the size and technology of semiconductor chips.

ROM is always found on motherboards, but is increasingly found on graphics cards and

some other expansion cards and peripherals. Generally speaking, ROM does not

change.

RAM, or Random Access Memory, is "volatile." This means that it only holds data while

power is present. RAM changes constantly as the system operates, providing the

storage for all data required by the operating system and software.


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History of ROM

The simplest type of solid state ROM is as old as semiconductor technology itself.

Combinational logic gates can be joined manually to map n-bit address input onto

arbitrary values of m-bit data output (a look-up table). With the invention of the

integrated circuit came mask ROM. Mask ROM consists of a grid of word lines (the

address input) and bit lines (the data output), selectively joined together with transistor

switches, and can represent an arbitrary look-up table with a regular physical layout and

predictable propagation delay.

In mask ROM, the data is physically encoded in the circuit, so it can only be

programmed during fabrication. This leads to a number of serious disadvantages:

1. It is only economical to buy mask ROM in large quantities, since users must

contract with a foundry to produce a custom design.

2. The turnaround time between completing the design for a mask ROM and

receiving the finished product is long, for the same reason.

3. Mask ROM is impractical for R&D work since designers frequently need to

modify the contents of memory as they refine a design.

4. If a product is shipped with faulty mask ROM, the only way to fix it is to recall theproduct and physically replace the ROM.

Subsequent developments have addressed these shortcomings. PROM, invented in

1956, allowed users to program its contents exactly once by physically altering its

structure with the application of high-voltage pulses. This addressed problems 1 and 2

above, since a company can simply order a large batch of fresh PROM chips and

program them with the desired contents at its designers' convenience. The 1971

invention of EPROM essentially solved problem 3, since EPROM (unlike PROM) can be

repeatedly reset to its unprogrammed state by exposure to strong ultraviolet light.

EEPROM, invented in 1983, went a long way to solving problem 4, since an EEPROM

can be programmed in-place if the containing device provides a means to receive the

program contents from an external source (e.g. a personal computer via a serial cable).
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Flash memory, invented at Toshiba in the mid-1980s, and commercialized in the early

1990s, is a form of EEPROM that makes very efficient use of chip area and can be

erased and reprogrammed thousands of times without damage.

Figure 1: The first EPROM, an Intel 1702, with the die and wire bonds clearly visible through the erase

window.

All of these technologies improved the flexibility of ROM, but at a significant cost-per-

chip, so that in large quantities mask ROM would remain an economical choice for

many years. (Decreasing cost of reprogrammable devices had almost eliminated the

market for mask ROM by the year 2000.) Furthermore, despite the fact that newer

technologies were increasingly less "read-only," most were envisioned only as

replacements for the traditional use of mask ROM.

The most recent development is NAND flash, also invented by Toshiba. Its designers

explicitly broke from past practice, stating plainly that "the aim of NAND Flash is to

replace hard disks,"[2] rather than the traditional use of ROM as a form of non-volatile

primary storage. As of 2007, NAND has partially achieved this goal by offering

throughput comparable to hard disks, higher tolerance of physical shock, extreme

miniaturization (in the form of USB flash drives and tiny microSD memory cards, for

example), and much lower power consumption.
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Use for storing programs

Every stored-program computer needs some form of non-volatile storage (that is,

storage that retains its data when power is removed) to store the initial program that

runs when the computer is powered on or otherwise begins execution (a process known

as bootstrapping, often abbreviated to "booting" or "booting up"). Likewise, every non-

trivial computer needs some form of mutable memory to record changes in its state as it

executes.

Forms of read-only memory were employed as non-volatile storage for programs in

most early stored-program computers, such as ENIAC after 1948 (until then it was not a

stored-program computer as every program had to be manually wired into the machine,

which could take days to weeks). Read-only memory was simpler to implement since it

needed only a mechanism to read stored values, and not to change them in-place, and

thus could be implemented with very crude electromechanical devices (see historical

examples below). With the advent of integrated circuits in the 1960s, both ROM and its

mutable counterpart static RAM were implemented as arrays of transistors in silicon

chips; however, a ROM memory cell could be implemented using fewer transistors than

an SRAM memory cell, since the latter needs a latch (comprising 5-20 transistors) to

retain its contents, while a ROM cell might consist of the absence (logical 0) or

presence (logical 1) of one transistor connecting a bit line to a word

line.[3]Consequently, ROM could be implemented at a lower cost-per-bit than RAM for

many years.

Most home computers of the 1980s stored a BASIC interpreter or operating system in

ROM as other forms of non-volatile storage such as magnetic disk drives were too

costly. For example, theCommodore 64 included 64 KB of RAM and 20 KB of ROM

contained a BASIC interpreter and the "KERNAL" of its operating system. Later home or

office computers such as the IBM PC XT often included magnetic disk drives, and larger

amounts of RAM, allowing them to load their operating systems from disk into RAM,

with only a minimal hardware initialization core and bootloader remaining in ROM

(known as the BIOS in IBM-compatible computers). This arrangement allowed for a

more complex and easily upgradeable operating system.
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In modern PCs, "ROM" (or Flash) is used to store the basic bootstrapping firmware for

the main processor, as well as the various firmware needed to internally control self

contained devices such asgraphic cards, hard disks, DVD drives, TFT screens, etc, in

the system. Today, many of these "read-only" memories especially the BIOS are

often replaced with Flash memory (see below), to permit in-place reprogramming should

the need for a firmware upgrade arise. However, simple and mature sub-systems (such

as the keyboard or some communication controllers in the ICs on the main board, for

example) may employ mask ROM or OTP (one time programmable).

ROM and successor technologies such as Flash are prevalent in embedded systems.

These are in everything from industrial robots to home appliances and consumer

electronics (MP3 players, set-top boxes, etc) all of which are designed for specific

functions, but are based on general-purpose microprocessors in most cases. With

software usually tightly coupled to hardware, program changes are rarely needed in

such devices (which typically lack devices such as hard disks for reasons of cost, size,

and/or power consumption). As of 2008, most products use Flash rather than mask

ROM, and many provide some means for connecting to a PC for firmware updates; for

example, a digital audio player might be updated to support a new file format. Some

hobbyists have taken advantage of this flexibility to reprogram consumer products for

new purposes; for example, the iPodLinux and OpenWRT projects have enabled users

to run full-featured Linux distributions on their MP3 players and wireless routers,

respectively.

ROM is also useful for binary storage of cryptographic data, as it makes them difficult to

replace, which may be desirable in order to enhance information security.

Use for storing data

Since ROM (at least in hard-wired mask form) cannot be modified, it is really only

suitable for storing data which is not expected to need modification for the life of the

device. To that end, ROM has been used in many computers to store look-up tables for

the evaluation of mathematical and logical functions (for example, a floating-point
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unit might tabulate the sine function in order to facilitate faster computation). This was

especially effective when CPUs were slow and ROM was cheap compared to RAM.

Notably, the display adapters of early personal computers stored tables of bitmapped

font characters in ROM. This usually meant that the text display font could not bechanged interactively. This was the case for both the CGA and [[Monochrome Display

Adapter|MDA] adapters available with the IBM PC XT.

The use of ROM to store such small amounts of data has disappeared almost

completely in modern general-purpose computers. However, Flash ROM has taken over

a new role as a medium for mass storage or secondary storage of files.

Historical examples

Figure 1.2:Transformer matrix ROM (TROS), from the IBM System 360/20

Diode matrix ROM, used in small amounts in many computers in the 1960s as

well as electronic desk calculators and keyboard encoders for terminals. This

ROM was programmed by installing discrete semiconductor diodes at selected

locations between a matrix of word line tracesand bit line traceson a printedcircuit board.

Resistor, capacitor, or transformer matrix ROM, used in many computers until the

1970s. Like diode matrix ROM, it was programmed by placing components at

selected locations between a matrix of word linesand bit lines. ENIAC's Function

Tables were resistor matrix ROM, programmed by manually setting rotary
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switches. Various models of the IBM System/360 and complex peripheral

devices stored their microcode in either capacitor (called BCROSfor balanced

capacitor read-only storageon the 360/50 & 360/65, or CCROSfor card

capacitor read-only Storageon the 360/30) or transformer

(called TROSfortransformer read-only storageon the 360/20, 360/40 and

others) matrix ROM.

Core rope, a form of transformer matrix ROM technology used where size and/or

weight were critical. This was used inNASA/MIT's Apollo Spacecraft

Computers, DEC's PDP-8 computers, and other places. This type of ROM was

programmed by hand by weaving "word line wires" inside or outside

of ferrite transformer cores.

The perforated metal character mask ("stencil") in Charactron cathode ray tubes,

which was used as ROM to shape a wide electron beam to form a selected

character shape on the screen either for display or a scanned electron beam to

form a selected character shape as an overlay on a video signal.

Reading

Although the relative speed of RAM vs. ROM has varied over time, large RAM chips can

be read faster than most ROMs. For this reason (and to allow uniform access), ROM

content is sometimes copied to RAM or shadowed before its first use, and

subsequently read from RAM.

Writing

For those types of ROM that can be electrically modified, writing speed is always much

slower than reading speed, and it may need unusually high voltage, the movement ofjumper plugs to apply write-enable signals, and special lock/unlock command codes.

Modern NAND Flash achieves the highest write speeds of any rewritable ROM

technology, with speeds as high as 15MB/s (or 70 ns/bit), by allowing (needing) large

blocks of memory cells to be written simultaneously.
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TYPES OF ROM

PROM

PROM (Programmable Read Only Memory) memories were developed at the end of the

70s by a company called Texas Instruments. These memories are chips comprising

thousands of fuses (or diodes) that can be "burnt" using a device called a " ROM

programmer", applying high voltage (12V) to the memory boxes to be marked. The

fuses thus burnt correspond to 0 and the others to 1.

EPROM

EPROM (Erasable Programmable Read Only Memory) memories are PROMs that can

be deleted. These chips have a glass panel that lets ultra-violet rays through. When the

chip is subjected to ultra-violet rays with a certain wavelength, the fuses are

reconstituted, meaning that all the memory bits return to 1. This is why this type of

PROM is called erasable.

EEPROM and Flash EEPROM memory

EEPROM (Electrically Erasable Read Only Memorymemories are also erasable

PROMs, but unlike EPROMs, they can be erased by a simple electric current, meaning

that they can be erased even when they are in position in the computer.

There is a variant of these memories known as flash memories (also Flash

ROMor Flash EPROM). Unlike the classic EEPROMs that use 2 to 3 transistors for

each bit to be memorised, the EPROM Flash uses only one transistor. Moreover, the

EEPROM may be written and read word by word, while the Flash can be erased only in

pages (the size of the pages decreases constantly).


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IMAGES OF PROM

Figure 1.3: N82S129AN PROM Figure 1.4: 24502457 PROM

Figure 1.5: CI202A PROM Figure 1.6: 1302 PROM


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EPROM

Figure 1.7: Intel D2764A-3 EPROM Figure 1.8: AMD 8327 JPP EPROM

Figure 1.9: M27C2568 EPROM Figure 1.10: D4464C EPROM

Figure 1.11: PROM


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EEPROM

Figure 1.12: NECs EEPROM Figure 1.13: Michochip EEPROM

Figure 1.14: K1S206 EEPROM Figure 1.15: Amibios EEPROM

Figure 1.16: EEPROM in Motherboard


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LATEST TECHNOLOGY OF ROM

CD-ROM

Short for Compact Disc-Read-Only Memory, a type of optical disk capable of storinglarge amounts of data -- up to 1GB, although the most common size is 650MB

(megabytes). A single CD-ROM has the storage capacity of 700 floppy disks, enough

memory to store about 300,000 text pages.

CD-ROMs are stampedby the vendor, and once stamped, they cannot be erased and

filled with new data. To read a CD, you need a CD-ROM player. All CD-ROMs conform

to a standard size and format, so you can load any type of CD-ROM into any CD-ROM

player. In addition, CD-ROM players are capable of playing audio CDs, which share the

same technology.

CD-ROMs are particularly well-suited to information that requires large storage capacity.

This includes large software applications that support color, graphics, sound, and

especially video.

Today's mass produced CD-ROM drives are faster and cheaper than they've ever been.

Consequently, not only is a vast range of software now routinely delivered on CD-ROM,

but many programs (databases, multimedia titles, games and movies, for example) are

also run directly from CD-ROM - often over a network. The CD-ROM market now

embraces internal, external and portable drives, caddy- and tray-loading mechanisms,

single-disc and multichanger units, SCSI and EIDE interfaces, and a plethora of

standard.
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DVD ROM

A new type of read-only compact disc that can hold a minimum of 4.7GB (gigabytes),

enough for a full-length movie. The DVD-ROM specification supports disks with

capacities of from 4.7GB to 17GB and access rates of 600 KBps to 1.3 MBps. One of

the best features of DVD-ROM drives is that they are backward-compatible with CD-

ROMs. This means that DVD-ROM players can play old CD-ROMs, CD-I disks, and

video CDs, as well as new DVD-ROMs. Newer DVD players can also read CD-R disks.

A DVD Rom is similar to a CD Rom except that it can access a recordable or rewritable

DVD disk. With this specific technology, the DVD disk can store up to 25 times more

data than a standard CD Rom disc. With a DVD Rom drive, movies can be watched,

games and music can be played and much more. DVD Rom drives are also backward

compatible with CD Rom disks, which means they can play these older disks.

Figure 1.17: Sample of DVD-RW

Figure 1.18: Sample of DVD-RW
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2) History of RAM

Figure 2.1: 1 Megabit chip - one of the last models developed by VEB Carl Zeiss Jena in 1989

An early type of widespread writablerandom-access memory was magnetic, developed

from 1955 to 1975, and subsequently used in most computers up until the development

and adoption of the static and dynamic integrated RAM circuits in the late 1960s and

early 1970s. Before this, computers used relays, delay line/delay memory, or various

kinds of vacuum tube arrangements to implement "main" memory functions (i.e.,

hundreds or thousands of bits), some of which were random access, some not. Memory

could be expanded at low cost but retrieval of non-sequential memory items required

knowledge of the physical layout of the drum to optimize speed. Latches built out of

vacuum tube triodes, and later, out of discrete transistors, were used for smaller and

faster memories such as random-access register banks and registers. Prior to the

development of integrated ROM circuits, permanent(or read-only) random-access

memory was often constructed using semiconductor diode matrices driven by address

decoders, or specially wound core memory planes.

During 1949 to 1952, the magnetic core memory was widely used as a writable random

access memory. It was subsequently used in most computers, until the development ofthe static and dynamic integrated RAM circuits in the late 1960s and early 1970s.

Before RAM, computers used delay line memory, relays and different kinds of vacuum

tube arrangements to implement main memory functions, which were a few hundreds or

thousands of bits. Latches built out of vacuum tube triodes and discrete transistors were

used for smaller and faster memories such as registers and random access register
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banks. Before integrated ROM circuits were developed, random access memory was

constructed using semiconductor diode matrices which were driven by address

decoders.

Magnetic core memory, the earliest form of random access memory, was developed inthe late 1940s and early 1950s. This form of memory has metallic wires threaded

through magnetic rings and used polarity to store information. As with drum memory,

magnetic core memory was short-lived, but the word "core" survived.

A semiconductor is any material that promotes the flow of electricity. The advent of

semiconductor technology in the 1970s gave rise to today's random access memory.

The first company to create, manufacture and market an economical semiconductor

core memory was Intel. The company began work in 1968 and introduced a 64-bit RAM

chip in 1969. In the same year, Intel released a 256-bit chip, the first commercial use of

a silicone-based semiconductor for computer memory. For the last 40 years,

semiconductors have been the basis for all RAM technology.

TYPES OF MEMORY

One of the types of memory computers use is Random Access Memory, or RAM for

short. Several different RAM types have been made over the course of computer

history.

Dynamic RAM

Every form of modern RAM is known as Dynamic RAM, which allows the computer to

access the memory and store information in a variety of ways.

Figure 2.2: Sample of Dynamic RAM
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FPM RAM

Fast Page Mode was one of the first types of RAM. This type of RAM was prevalent in

computers made before 1995.

Figure 2.3: Sample of FPM RAM

EDO RAM

Extended Data Out RAM is a modified form of FPM RAM. The RAM allowed computers

to boost performance by 5 percent.

Figure 2.4: A sample of EDO RAM

SDRAM

Synchronous Dynamic RAM, or SDRAM, became the standard shortly after EDO RAM.

It performed at twice the speeds of EDO RAM, and three times as fast as FPM.

Figure 2.5: Sample of SD RAM


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DDR RAM

Double Data Rate RAM is the current standard for RAM. The RAM is considered a

"double clock standard" of SDRAM. DDR2 is a modified version of RAM that is installed

in most mid- and high-level computers.

Figure 2.6: Sample of DDR RAM

Diagram 2.1:The Computer Memory


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Description Picture

30-pin SIMM (Single In-line

Memory Module)

72-pin SIMM

168-pin DIMM (Dual In-line

Memory Module)

184-pin DIMM

Table 2.1: The RAM with the pins


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LATEST TECHNOLOGY OF RAM

There have been many different types of RAM memory in use since it first was used in

computers. The RAM memory used in current PCs comes in the form

of DDR and DDR2 and DDR3 memory modules. The correct type that thecomputer's motherboard supports has to be used. Some motherboards can support two

types, such as DDR and DRR2, but most motherboards only support one type. A kit

consisting of two 1GB modules of DDR2 memory, for use in a desktop PC, made

by Crucial, is shown below. The upper side with the notch and the metallic edge is

keyed to fit into the appropriate memory (DIMM) slot, therefore it cannot be installed in

the wrong type of slot unless the installer uses the kind of force that will probably

destroy the module.

On the semiconductor road map setting out the future of the microchip industry, current

memory technologies are nearing the end of the road. Future computers and electronic

gadgets will need memory chips that are smaller, faster and cheaper than those of

today and that means going back to basics.

Todays random-access memory (RAM) falls mainly into three classes: static RAM

(SRAM), dynamic RAM (DRAM), and flash memory. Each has its advantages and

drawbacks; flash, for instance, is the only one to retain data when the power is switched

off, but is slower. If we using a desktop computer, memory requirements depend on the

computer's operating system and the application software you're using. Today's word

processing and spreadsheet applications require as little as 32MB of memory to run.

However, software and operating system developers continue to extend the capabilities

of their products, which usually means greater memory requirements. Today,

developers typically assume a minimum memory configuration of 512MB. Systems used

for graphic arts, publishing, and multimedia call for at least 1GB of memory and it's

common for such systems to require 2GB or more for best performance.

There are some other issues that you should know about, such as running DDR, DDR2,

and DDR3 RAMin single-channel and dual-channel modes, so read the information in
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this article to make sure that you buy the correct memory for your computer's

motherboard or brand-name PC.

Note that Intel's Socket LGA1366 Core i7 quad-core processors now have a memory

controller onboard for the first time that can run DDR3 memory in triple-channel mode,

so the motherboards that run them have six DIMM memory slots in order to run two sets

of three modules in triple-channel mode. They can also run DDR3 memory in single

channel and dual-channel modes. AMD's processors have had an onboard memory

controller for many years.

It might be a stretch to file high-speed DDR3 under the mainstream label, but recent

pricing drops certainly make these parts attractive to mid-budget enthusiasts. Thats

because, while true mainstream parts have remained relatively expensive since last

summer, the difference in price between ordinary and enthusiast products has

narrowed. Buyers one year ago could expect to pay twice as much to get a 50% higher

data rate. Today, the pricedifference has now fallen to around 50%.

While our own tests have shown that super-high data rates really arent helpful for

adding program performance to modern desktop platforms, higher speeds areuseful for

retaining whatever an over clocker believes is an optimal DRAM multiplier, whilepushing the CPU frequency skyward. Many of todays competitors can even be viewed

as over clocking-only parts, since settings beyond DDR3-1600 are achievable only by

over clocking other parts of your system.
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LATEST TECHNOLOGYS RAM

Figure 2.7: Sample of DDR3 RAM Figure 2.8: Sample of DDR2 RAM

Figure 2.9: Sample of DDR3 RAM with Figure 2.10: Sample of DDR3 RAM for

some cooling technique laptop

.


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CONCLUSION

At last we had learned about the computers memory.

Read only memory (ROM).This is the permanent memory which is used to store

important control programs and systems software to perform a variety of functions, such

as booting up or starting up programs. ROM is non-volatile. That means the contents

are not lost when the power is switched off. Its contents are permanently written at the

time of manufacture.

Random access memory (RAM).RAM is used as the working memory of a computer

system. It stores input data, intermediate results, programs, and other information

temporarily. It can be read and written. It is volatile, that is all data will be erased whenthe power is turned off.

We hope the upcoming future technologies will more powerful and great than now. And,

it also will make our work to move easily.
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REFERENCES

http://en.wikipedia.org/wiki/EEPROM

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http://inventors.about.com/od/rstartinventions/a/Ram.htm

http://en.kioskea.net/contents/pc/rom.php3

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http://www.tme.eu/html/EN/eeproms-electrically-erasable-programmable-read-only-

memory/ramka_646_EN_pelny.html

http://en.wikipedia.org/wiki/Random-access_memory#History

http://www.buzzle.com/articles/what-is-computer-ram-random-access-memory.html

http://www.bittech.net/hardware/memory/2008/02/08/the_secrets_of_pc_memory_p

art_3/1

http://www.pcbuyerbeware.co.uk/RAM.htm

http://simple.wikipedia.org/wiki/Computer_memory

http://www.pctechguide.com/cd-rom
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