MRAM

Acquainted with MRAM

With MRAM, the computer turned on does not need to be awaited. In an instant, your computer will turn on lights like a calculator. Since MRAM has the speed of SRAM, Non-Volatile, without solid, and has a density in the DRAM.

Try to count, how many types of memory in your computer? At a minimum, there are three different types of memory in a PC. The first course is how you feel its presence is a hard disk. The second is the last RAM, rarely felt its presence, let alone by the cloud community, that is cache memory. Without all three of your computers will be very hard work.

Hard drive allows you to store all the data is done by computer. Without hard drive will be very difficult to store data. Then beguna RAM for temporary data storage. Existing capacity in the RAM was going to help the application including the operating system can run. While the last mentioned, have characteristics similar to RAM. That is, store data related to the work processor. All three work together to make your computer work.

Why should or three? why not one? Sure the computer not only be simpler, but also will be easier and cheaper. The answer is that none of them can give you what your computer needs fully. Memory that is faster, cheaper, and can store without electricity.

SRAM is used as cache memory is very expensive production cost, the most expensive of the three. However, also the fastest memory. Unfortunately, this memory needs electricity to simply store data. RAM is now using DRAM technology. Much cheaper than SRAM, but not as fast as the speed of SRAM. Characteristics that require electricity to store data can not make RAM for storing data. Therefore, RAM only as a bridge between the hard disk with the data cache memory.

Your computer is not always going to use three types of memory. Because now found a new type of memory that has all the characteristics of the three memory had no weaknesses. It acts almost as fast as RAM with affordable price and does not require electricity to store data. This memory is called Magneto resistive Random Access Memory, or MRAM abbreviated. 

 

Some time ago, Reescale, a semiconductor company in Arizona, the United States announced that it has able to make a 4 MB MRAM for 90 nm with a machine.It is still very small compared to DRAM or flash disk. However, this remains a very good progress. Freescale is not the only company that develops MRAM technology.There's Samsung, Honeywell, NEC, Toshiba, Sony, and others. Even IBM has managed to develop MRAM for 16 MB to 180 nm engine.

One of the missions carried by this MRAM is shorten the booting process and is always ready to take the computer when turned on. You do not need anymore waiting for the computer to load the operating system from disk into RAM. Within seconds the computer will be ready for use. Just as you turn on your phone or a calculator.

Classified as solid MRAM memory because there is no single mechanical components like hard drives. MRAM is already started to be developed since 30 years ago. Since then MRAM has several developments that make it faster and higher density. The following description outlines how an MRAM is made and how it works.

MRAM cell is composed of several magnetic. Each cell is composed of two ferromagnetic metal layers separated by insulating layers. One of the layers contain a fixed magnetic field (bottom layer). Meanwhile, the other one will vary according to the stored information. On the top layer is composed electrical path parallel to the cell. And under the lower ferromagnetic layer is the electrical current path lined 90-degree angle with the linta san. So that if viewed these lines will form like a mosquito net.

If the reading process in progress, then there is only one path only to be used. Electrical path that is above the layer of cells. If a layer indicating a high resistance to the flow, then reads the information is "1". Conversely, if low-resistance layer, meaning stored information is "0". The second big difference in the resistance of these conditions is 23s.

Both differences can be determined by the condition of the current value of the exit. To make the process of reading an electric current will run on one track and read the resistance megetahui cel for existing information within the cell. And to make writing a transistor is not active so the current will be through two paths at once. Writing occurs because the current flow across the memory cell to change the polarity of one of the ferromagnetic layer.

Perpendicular Recording

The need for hard disk storage not only used on the PC. Some consumer electronics also requires hard disk. For example, portable multimedia player competing offers greater capacity, or a mobile phone that supports multimedia. If on the PC, hard drive capacities are required to have a greater hold, then the consumer electronic physical size required to trigger the development of technology mengecil.Ini used hard drive. Technology solutions that are used is perpendicular recording.

Why is perpendicular Recording Necessary?

Disk stores data on a magnetic plate. This is a major challenge for producers hard disk, which is designing a storage medium magnetic reliable. Where the size of a magnetic region, is proportional to the energy required to demagnetized. The larger magnetic region, the more stable data. This of course is reversed with the needs of storage media, who crave large capacity, without increasing the size dimension big. Physical size or smaller with large data.

There is a minimum limit of a magnetic region will remain stable at room temperature. If less than the minimum limit, then the magnetic region will be easily changed at random magnetic poles. Perpendicular recording is the alternative used, because this technique does not reduce the size of the magnetic regions. Just change the layout orientation, in order to more efficiently use this terbatas.Hal place that can not be achieved by relying on longitudinal recording, as used on the hard drive for this.

How does perpendicular recording?

Change direction perpendicular recording bits on the pole orientation of magnetic elements. Compared to longitudinal (standard) recording, the direction parallel to the magnetic poles plate on the disk. While in perpendicular recording, the magnetic pole pointing perpendicular to the plate. More specifically, can be seen in the illustration.

By setting the magnetic polar regions are perpendicular (perpendicular) of the surface of the media, making the distance between regions even closer. Indirectly also reproduce the data capacity, in a same surface area.
To apply this method requires an additional layer. Material used in this additional layer, useful to set the direction of the magnetic pole orientation.

This layer lies between the pieces of plate, and the magnetic layer of the film. By using the perpendicular recording method, allowing the use of magnetic materials, with the coefficient of magnetic (coercivity) is higher. This means that the magnetic field takes a larger, to be able to change the existing magnetic field. Or in short, more stable. It allows the use of materials with magnetic grains, which require magnetic regions are much smaller. Thus overall, perpendicular recording will heighten the level of data density, on each chip used.

The use of perpendicular recording.

Toshiba is the first manufacturer to produce a perpendicular recording hard drive with a 1.8 inch form factor, in the year 2005. Unfortunately, These products have problems in terms of stability and reliability of data. In January 2006, Seagate produces harddisik with this technology, intended for notebooks with 2.5-inch form factor. Seagate Momentus 5400.3 is the first product. Starting from here, Seagate will introduce the use of this technology, the next most hard drive products.

Of course, this step was followed by the other hard drive manufacturer. Seagate began to introduce 3.5-inch hard drive with perpendicular recording, in April 2006. Cheetah 15K.5 begins with a capacity of 300 GB, the rpm for spindle15.000 speed SCSI interface. This hard drive is claimed to have increased performance up to 30%, compared to the previous Cheetah series. For ATA interface, Seagate Barracuda 7200.10 to start with. Hard drive with 3.5-inch form factor, with a maximum capacity of 750 GB.

Toshiba also uses perpendicular recording to harddisk2, 5-inch, 200 GB capacity. This product was announced in June 2006, but the new will available on the market in August 2006. This will provide an opportunity to notebook users, to use the hard drive with 200 GB capacity. Fujitsu will begin to inform using perpendicular technology recording in August 2006, starting with 2.5-inch hard drives, with SATA interface, capacity of 160 GB. Hitachi Microdrive will apply to the capacity of 20 GB, and 1 TB for 3.5-inch hard drive. This product will be available in the year 2007.

SMART Technology

Self-Monitoring, Analysis, and Reporting Technology, or SMART abbreviated, is a disk monitoring system. With SMART, hard drive capable of detecting and report various indicators related to the reliability of data, with the aim anticipate the occurrence of damage.

 

SMART Function
 

Basically, the drive may have failed to function on the basis of two class divisions, namely:

- A predictable failure.
Like the mechanical age, with duration of use. SMART monitoring system can detect things like this. Disk can provide status, before experiencing malfunction.

- Failure that can not be predicted. 

Such damage, caused for example damage to electronic components, due to fire, or other physical damage.

Based on existing data, 60% damage to your hard disk can actually predict the time. And this is mostly due to the mechanical age. SMART can warn the user before it happened, and provide the opportunity to perform the necessary preventive measures, such as backing up data.

 

Standards and Implementation
 

SMART pioneered by Compaq. However, almost all hard disk and motherboard manufacturers, is using it. Typically, the motherboard will display a message at BIOS POST report.

However, there are still some compatibility issues for SMART. Some hard disk manufacturers sometimes called SMART compatible products, but sometimes not for all the reporting functions available on SMART. Say to not include temperature sensors, which may be interpreted by the user is expected to refer to the SMART compatible. Disk temperature is one important factor, which also affects its reliability.

Good facilities in the motherboard also SMART monitoring software, may not be able to report all SMART attributes. This can be caused due to the limited use interface. Say when using an external hard drive, with USB or FireWire interface. The same thing can happen to your hard drive with RAID mirroring configuration. Moreover, the monitor software RAID works in the operating system environment. This is because the operating system is not possible to see the individual disk, RAID configurations beyond.

SMART Attributes
 

If the ideal conditions, both hard drives are used, the interface used hard disk, motherboards, and monitors the SMART software is used, it's pretty much attribute information that can be displayed.

Each attribute will list the value between 1 to 253. Smallest value (1) states the value or the worst conditions. Whereas the highest value (253) claimed the best conditions. Each manufacturer has different limits to determine the normal conditions. Usually hard disk are still expressed in normal conditions, if the attribute value is not less than 100. If this is still considered too much trouble, you just see the results of the assessment conclusions Fitness and Performance.

Access and Interfaces

During the history of a long drive, he uses many types of interface. We used ST-506 interface, still using the method of encoding data Modified Frequency Modulation (MFM). A data encoding is also used on floppy disks. Data transfer rate capable generated by this interface is 5 Mbps (Mega bits per second). Then slightly increased with use of 2.7 RLL encoding method, to reach the number of data transfer rate of 7.5 Mbps.

In Enhanced Small Disk Interface (ESDI), supports the use of multiple data rates. Hard disk and automatically adjusts the controller, in accordance with the attached device. Data transfer rate is able to produce 10, 15 and 20 Mbps. Initially, the SCSI is a rapid transfer rate, which is 5 Mbps. Then This single interface that dramatically increases. In the device interface to this, there is no limits. The use of buffers, both at the SCSI bus controller, or also on the drive it self, allows this. ATA drives have the advantage of the integrated controller. Initially made little problem with compatibility. Especially in the configuration master / slave, where two drives are connected with a data cable.

This problem is resolved in the 1990s, when the ATA began to standardized specifications. Although there is still a problem, when incorporating the device DMA (direct memory access) and non-DMA. Serial ATA eliminates the master and slave configuration. Each drive is served by a single-channel I / O exclusively, with a data cable.

Alternative use of FireWire / IEEE 1394 and USB (1.0/2.0) is also becoming known lately. Actually, in the device is an ATA or SATA drives, which added to the adapter interface to USB or FireWire. Besides can be used externally, this alternative is also used because of its simplicity. No need to add a port or hard disk controller card, if the number of available ports is no longer sufficient.

Hard Disk Capacity and Features

Hard Disk Capacity and Features

Disks and enclosures with a much more robust than other storage media, hard drives have endurance allows higher. Capacity is much larger, with data transfer speeds much faster. Now, is not rare to hear the hard drive with capacities up to 500 GB, and spindel speeds up to 10,000 rpm. This can result sequential transfer speed 80 MB / s. Whereas for notebook hard disks, already available by 7200 rpm for high performance. That's the main advantage disk, compared to other storage media.

Plat on Disk Technology

Actually, the disk plate in the disk made of non-magnetic material. The most widely used material is glass (Si-Ge) or aluminum. And then coated with a layer of thin magnetic materials. Previous disk-disk using a magnetic coating material of iron (III) oxide. As for hard drives is now using a mixture of materials cobalt and aluminum. This is more minimize the risk of corrosion, and make it more reliable.

Magnetic layer on the disk plate, divided into very small regions. Each region represents 1 binary unit of data information is written. In the magnetic region, there are magnetic grains, which each have their own poles. When data is written, it is expected the combined magnetic field of magnetic grains will produce a particular pole. Each magnetic region will have a magnetic field with a particular magnetic pole, according to the data.

The process of encoding data, by reading the magnetic pole changes, from one magnetic region to another region. If there is a change (reverse) between regions and another reverse in the next region, will be regarded as '1 '. If no changes (no reverse) and then there is a change in the next region (reverse), regarded as '0 '.

The task was read head that reads changes in the magnetic fluctuations in the region. In the previous disk, read head of a very small inductor. Equipped with paramagnetic materials, to strengthen the sensitivity. When through the border region of magnetic read head will have a magnetic flux. By the inductor, this flux will be converted into electricity.

In the latest hard drives, is no longer using inductors, but the use of Giant Magnetoresistive effect, which is a breakthrough in quantum mechanics. Making more sensitive read head again, also maintain data reliability

Why Use Magnetic Grains?

One of the main objectives used magnetic grains (magnetic beads) is shrinkage space required, compared with continuous medium magnetic. With magnetic beads, the distance between the magnetic transition region can be made more minimal. The smaller the magnetic beads are used, the smaller the distance too transitions between regions.

Enclosures or Layer Packaging

Disk that we see in the visible layer of the wrapper (enclosures). Its main task is to ensure internal device protected from dust, humidity, and other external factors that allow data damage. Read-write head on the hard drive to move only a distance of nanometers unit, above the surface of the disk fragments.

Imagine if the disk is not equipped enclosures. Distance as thin as this could change, just because the air pressure by blowing air, dust, fingerprints, and so on.

If you look at the specifications of a hard drive, see also the operational range for the height of the water surface. In essence, the air pressure in the surrounding disk. This will affect the pressure in the disk packaging. Enclosure in this harddsik was deliberately not made resistant air pressure, breath due to filters, the main function of the heat released in the enclosures

If the air pressure is too low, causing the distance between the head and pieces data too closely. There is the possibility of head and pieces of data layers rub together, which can cause data loss.

High humidity levels also trigger the acceleration of corrosion damage on the hard drive, especially on the data and head pieces. On disk with the technology CSS (Contact Start / Stop), heads will park themselves on pieces of data, when idle. With high levels of humidity, corrosion between head and disk higher risk

Dissected Harddisk

Disk composed of spindle rotation is the center piece of one or more data storage media. This spindle rotates quickly. For that, use high quality bearings. In the previous hard disk was still relying on ball bearings, but for the latest drive is to use fluid bearings. With a fluid bearing, friction is happening more and more minimal, as well as increasing the noise level minimal.

This chip or disk that stores digital data, on the magnetic surface. Read or write process performed by the read-write head, the chip spinning at high speed. Read-write head is flying with a very thin range with a magnetic medium (usually a layer of film). Changing the magnetic poles are mikroskospik, according to the data written information. For the read process, a magnetic sensor to read magnetic flux from that location. Of the read sensor, the information is translated back into digital, 0 and 1.

Each chip or disk will have one head. If the amount is more than one chip, it will automatically adjust the amount of head. This is because the movement of only the radial head, according to the spindle. Head will not move up and down between the disks.

Movement of spindle rotation, the read and write disk or other activities, controlled locally by the disk controller. he who determines the efficiency of the implementation process of read and write. Development of the latest firmware for the disk controller, allowing more efficient again. Well done remapping allows the failed disk sector operates. That is why, in the latest hard drive, no longer found bad sectors.

Self-monitoring, analysis, and reporting technology (SMART) is also a an important feature in the hard disk. SMART is sent to the motherboard, to give early warning to the user, if the malfunction occurs that allows data damage.