What is dram memory slot

what is dram memory slot

Dram Memory Slot

Nov 16,  · Updated: 11/16/ by Computer Hope. A memory slot, memory socket, or RAM slot allows RAM (computer memory) to be inserted into the computer. Most motherboards have two to four memory slots, which determine the type of RAM used with the computer. The most common RAM types are SDRAM and DDR for desktop computers and SODIMM for laptop computers, each having . Feb 09,  · Stands for "Dynamic Random Access Memory." DRAM is a type of RAM that stores each bit of data on a separate capacitor. This is an efficient way to store data in memory, because it requires less physical space to store the same amount of data than if it was stored statically. Therefore, a DRAM chip can hold more data than an SRAM (static RAM) chip of the same size can. However, the .

Dynamic random-access memory dynamic RAM or DRAM is a type of random-access semiconductor memory that stores each bit of data in a memory cell consisting of a tiny capacitor and a transistorboth typically based on metal-oxide-semiconductor MOS technology. The capacitor can either be charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1.

The electric charge on the capacitors slowly leaks off, so without intervention the data on the chip would soon be lost. To prevent this, DRAM requires an external memory refresh circuit which periodically rewrites the data in the capacitors, restoring them to their original charge. This refresh process is the defining characteristic of dynamic random-access memory, in contrast to static random-access memory SRAM which does not require data what is dram memory slot be refreshed.

Unlike flash memoryDRAM is volatile memory vs. However, DRAM does exhibit limited data remanence. DRAM chips are widely used in digital electronics where low-cost and high-capacity computer memory is required. One of the largest applications for DRAM is the main memory colloquially called the "RAM" in modern computers and graphics cards where the "main memory" is called the graphics memory. It is also used how to remove cleanmymac 2 many portable devices and video game consoles.

In contrast, SRAM, which is faster and more expensive than DRAM, is typically used where speed is of greater concern than cost and size, such as the cache memories in processors. Due to its need of a system to perform refreshing, DRAM has more complicated circuitry and timing requirements than SRAM, but it is much more widely used. The advantage of DRAM is the structural simplicity of its memory cells: only one transistor and a capacitor are required per bit, compared to four or six transistors in SRAM.

The transistors and capacitors used are extremely small; billions can fit on a single memory chip. Due how do you read the torah the dynamic nature of its memory cells, DRAM consumes relatively large amounts of power, with different ways for managing the power consumption. Paper tape was read and the characters on it "were remembered in a dynamic store.

The store used a large bank of capacitors, which were either charged or not, a charged capacitor representing cross 1 and an uncharged capacitor dot 0. Since the charge gradually leaked away, a periodic pulse was applied to top up those still charged hence the term 'dynamic' ". In Arnold Farber and Eugene Schlig, working for IBM, created a hard-wired memory cell, using a transistor gate and tunnel diode latch. They replaced the latch with two transistors and two resistorsa configuration that became known as the Farber-Schlig cell.

That year they submitted an invention closure, but it was initially rejected. The Toshiba "Toscal" BC electronic calculatorwhich was introduced in November[7] [8] used a form of capacitive DRAM bit built from discrete bipolar what color is alicia keys cells.

The earliest forms of DRAM mentioned above used bipolar transistors. While it offered improved performance over magnetic-core memorybipolar DRAM could not compete with the lower price of the then-dominant magnetic-core memory. InDr. While examining the characteristics of MOS technology, he found it was capable of building capacitors, and that storing a charge or no charge on the MOS capacitor could represent the 1 and 0 of a bit, while the MOS transistor could control writing the charge to the capacitor.

This bit chip was sold to HoneywellRaytheonWang Laboratoriesand others. This became the Intel in early This became the first commercially available DRAM, the Intelin Octoberdespite initial problems with low yield until the fifth revision of the masks. The was designed by Joel Karp and laid out by Pat Earhart. The masks were cut by Barbara Maness and Judy Garcia. This addressing scheme uses the same address pins to receive the low half and the high half of the address of the memory cell being referenced, switching between the two halves on alternating bus cycles.

This was a radical advance, effectively halving the number of address lines required, which enabled it to fit into packages with fewer pins, a cost advantage that grew what is dram memory slot every jump in memory size. The MK proved to be a very robust design for customer applications. However, as density increased to 64 kbit in the early s, Mostek and other US manufacturers were overtaken by Japanese DRAM manufacturers, which dominated the US and worldwide markets during the s and s.

Inwhen 64K DRAM memory chips were the most common memory chips used in computers, and when more than 60 percent of those chips were produced how to eat shitake mushrooms Japanese companies, semiconductor makers in the United States accused Japanese companies of export dumping for the purpose of driving makers in the United States out of the commodity memory chip business.

DRAM is usually arranged in a rectangular array of charge storage cells consisting of one capacitor and transistor per data bit. The figure to the right shows a simple example with a four-by-four cell matrix.

Some DRAM matrices are many thousands of cells in height and width. The long horizontal lines connecting each row are known as word-lines. Each column of cells is composed of two bit-lines, each connected to every other storage cell in the column the illustration to the right does not include this important detail. A sense amplifier is essentially a pair of cross-connected inverters between the bit-lines.

This results in positive feedback which stabilizes after one bit-line is fully what is dram memory slot its highest voltage and the other bit-line is at the lowest possible voltage. To store data, a row is opened and a given column's sense amplifier is temporarily forced to the desired high or low voltage state, thus causing the bit-line to charge what is my verizon mobile email address discharge the cell storage capacitor to the desired value.

Due to the sense amplifier's positive feedback configuration, it will hold a bit-line at stable voltage even after the forcing voltage is removed. During a write to a particular cell, all the columns in a row are sensed simultaneously just as during reading, so although only a single column's storage-cell capacitor charge how to apply brisa gel changed, the entire row is refreshed written back inas illustrated in the figure to the right.

Typically, manufacturers specify that each row must be refreshed every 64 ms or less, as defined by the JEDEC standard. Some systems refresh every row in a burst of activity involving all rows every 64 ms.

Other systems refresh one row at a time staggered throughout the 64 ms interval. A few real-time systems refresh a portion of memory at a time determined by an external timer function that governs the operation of the rest of a system, such as the vertical blanking interval that occurs every 10—20 ms in video equipment.

The how to get oklahoma drivers license address of the row that will be refreshed next is maintained by external logic or a counter within the DRAM.

A system that provides the row address and the refresh command does so to have greater control over when to refresh and which row to refresh.

This is done to minimize conflicts with memory accesses, since such a system has both knowledge of the memory access patterns and the refresh requirements of the DRAM.

When the row address is supplied by a counter within the DRAM, the system relinquishes control over which row is refreshed and only provides the refresh command. Many parameters are required to fully describe the timing of DRAM operation. Here are some examples for two timing grades of asynchronous DRAM, from a data sheet published in [30]. This is the time to read a random bit from a precharged DRAM array. The time to read additional bits from an open page is much less.

When such a RAM is accessed by clocked logic, the times are generally rounded up to the nearest clock cycle. For example, when accessed by a MHz state machine i. When describing synchronous memory, timing is described by clock cycle counts separated by hyphens.

Note that this is half of the data transfer rate when double data rate signaling is used. However, the DDR3 memory does achieve 32 times higher bandwidth; due to internal pipelining and wide how to make pop explode paths, it can output two words every 1. Each bit of data in a DRAM is stored as a positive or negative electrical charge in a capacitive structure. The structure providing the capacitance, as well as the transistors that control access how to calculate chiller approach temperature it, is collectively referred to as a DRAM cell.

They are the fundamental building block in DRAM arrays. The transistor is used to admit current into the capacitor during writes, and to discharge the capacitor during reads.

The access transistor is designed to maximize drive strength and minimize transistor-transistor leakage Kenner, pg. In modern DRAMs, the latter case is more common, since it allows faster operation. The electrical charge stored in the capacitor is measured in coulombs. Reading or writing a logic one requires the wordline is driven to a voltage greater than the sum of V CC and the access transistor's threshold voltage V TH.

The time required to discharge a capacitor thus depends on what logic value is stored in the capacitor. A capacitor containing logic one begins to discharge when the voltage at the access transistor's gate terminal is above V CCP. If the capacitor contains a logic zero, it begins to discharge when the gate terminal voltage is above V TH.

Up until the mids, the capacitors in DRAM cells were co-planar with the access transistor they were constructed on the surface what is dram memory slot the substratethus they were referred to as planar capacitors.

The drive to increase both density, and to a lesser extent, performance, required denser designs. The minimization of DRAM cell area can produce a denser device which could be sold at a higher priceor a lower priced device with the same capacity.

Starting in the mids, the capacitor has been moved above or below the silicon substrate in order to meet these objectives. DRAM cells featuring capacitors above the substrate are referred to as stacked or folded plate capacitors; whereas those with capacitors buried beneath the substrate surface are referred to as trench capacitors.

In the s, manufacturers were sharply divided by the type of capacitor used by their DRAMs, and the relative cost and long-term scalability of both designs has been the subject of extensive debate. The majority of DRAMs, from major manufactures such as HynixMicron TechnologySamsung Electronics use the stacked capacitor structure, whereas smaller manufacturers such Nanya Technology use the trench capacitor structure Jacob, pp. The capacitor in the stacked capacitor scheme is constructed above the surface of the substrate.

The capacitor is constructed from an oxide-nitride-oxide ONO dielectric sandwiched in between two layers of polysilicon plates the top plate is shared by all DRAM cells in an ICand its shape can be a rectangle, a cylinder, or some other more complex shape.

There are two basic variations of the stacked capacitor, based on its location relative to the bitline—capacitor-over-bitline COB and capacitor-under-bitline CUB. In a former variation, the capacitor is underneath the bitline, which is usually made of metal, and the bitline has a polysilicon contact that extends downwards to connect it to the access transistor's source terminal.

In the latter variation, the capacitor is constructed above the bitline, which is almost always made of polysilicon, but is otherwise identical to the COB variation. The advantage the COB variant possesses is the ease of fabricating the contact between the bitline and the access transistor's source as it is physically close to the substrate surface. However, this requires the active area to be laid out at a degree angle when viewed from above, which makes it difficult to ensure that the capacitor how do people get into poverty does not touch the bitline.

CUB cells avoid this, but suffer from difficulties in inserting contacts in between bitlines, since the size of features this close to the surface are at or near the minimum feature size of the process technology Kenner, pp. The trench capacitor is constructed by etching a deep hole into the silicon substrate.

A layer of oxide-nitride-oxide dielectric is grown or deposited, and finally the hole is filled by depositing doped polysilicon, which forms the top plate of the capacitor. The top of the capacitor is connected to the access transistor's drain terminal via a polysilicon strap Kenner, pp.

Trench capacitors have numerous advantages. Since how to get url value in php capacitor is buried in the bulk of the substrate instead of lying on its surface, the area it occupies can be minimized to what is required to connect it to the access transistor's drain terminal without decreasing the capacitor's size, and thus capacitance Jacob, pp. Alternatively, the capacitance can be increased by etching a deeper hole without any increase to surface area Kenner, pg.

Another advantage of the trench capacitor is that its structure is under the layers of metal interconnect, allowing them to be more easily made planar, which enables it to be integrated in a logic-optimized process technology, which have many levels of interconnect above what is dram memory slot substrate.

The fact that the capacitor is under the logic means that it is constructed before the transistors are. This allows high-temperature processes to fabricate the capacitors, which would otherwise be degrading the logic transistors and their performance. Disadvantages of trench capacitors are difficulties in reliably constructing the capacitor's structures within deep holes and in connecting the capacitor to the access transistor's drain terminal Kenner, pg.

Why are the memory slots different colors?

Stands for "Dynamic Random Access Memory. This is an efficient way to store data in memory, because it requires less physical space to store the same amount of data than if it was stored statically. This is the type of memory most computers use for their main system memory. If you choose to upgrade your computer's SDRAM, check your machine's requirements to see if the memory modules must be installed in pairs.

If so, you will need to replace two modules at once and they must be the same size i. This page contains a technical definition of DRAM. All definitions on the TechTerms website are written to be technically accurate but also easy to understand. If you find this DRAM definition to be helpful, you can reference it using the citation links above. If you think a term should be updated or added to the TechTerms dictionary, please email TechTerms! Subscribe to the TechTerms Newsletter to get featured terms and quizzes right in your inbox.

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