It is a very old trick to use a ram disk in order to boost PC performances, in the past, when in home environments the fastest common devices were floppy disks a part of the very small ram memory available was used to create a virtual hard drive, and was used to store critical data that had to be fast available and soon served to the PC.
The boost obtained in this way was simply outrageous and the very slow machines of those times (25 years ago) were in this way somehow well exploited.
As the technologies were constantly developed, faster and more reliable devices were spread on the market at all levels. Soon, we reached a condition for which a ram disk was not very important anymore in home environments, so the topic was less and less discussed or taken in consideration.
At present time, a ram disk is still an unknown item to the mass, and only in the last year many heard of the new SSD Hard disks.
SSD hard drives are composed of memory chips, the name of such a unit is Solid State Disk.
The chips can be of various kinds of flash memories and volatile standard RAM. They do not use an electromechanical system and metal disks to store the data.
Today the so commonly called SSD are mainly NAND flash memory based , this memory chips can store the data also when the power is cut off, prices going low and development going on, as of typical IT trend, made economically possible to launch on the mass market this devices.
Even though the initial high prices are already abated still a average price per GB for a SSD is many times higher that the average price per GB of a regular HD.
But there are also other drawbacks, technical issues and a limited life are the most evident.
In fact the SSD technology is very slow in taking foot in the shop shelf IT market and the reasons might be depending more on this factor than on the higher price.
A SSD can be also be done of volatile standard RAM banks only, in that case we can call it purely Hardware Ram Disk, technical limitations are present too but of a different kind and not on the perfomance side.
Which are the advantages of using chips to store data instead of a metal disk as common today?
The most evident and strong advantage is the amazing speed at which the controller can read and write the data on chips, but even more the incredibly 1000 times faster seek for the data, so meanwhile a regular very fast traditional hard disk still needs some milliseconds to find a data' position, the new SSD, and even better ram disks, need only nanoseconds to do the same work.
Furthermore, meanwhile traditional HD are relying on a mechanical system in the new SSD there is no moving parts at all, so the general reliability is just not even comparable.
Other strong advantages include a superior resistance to shocks and vibrations and a lower power consumption.
But still this kind of common SSD are not yet the best device for fast computing. In fact, the old concept of pure ram disk still is the winner when speed is desired or required.
So which is the difference between a SSD and a pure hardware ram disk?
The main difference is that a flash based common SSD can hold the data also when turned off, hardware ram disk does not. In fact, the chips used to make SSD are capable of keeping a given state even if electricity is not supplied.
Many sorts of common SSD have a limited life as the write cycles are finite on this kind of chips meanwhile the ram banks have the typical ideal life of transistors, so theoretically 1,000,000 hours of work and vitrually countless write cycles.
As the SSD chips have a finite number of write cycles their controllers take care to evenly wear them trough a process called wear leveling , being so forced to distribute data in a reasoned way through all the positions available in sequential cycles, there is a loss of time in order to respect this extra rule.
Furthermore, the wear leveling process is not compatible with encryption which is not secure on this kind of SSD, also secure deletion is not possible, only units that support the ATA command TRIM allow secure deletion of files as the blocks are cleaned in background before being written.
Therefore, SSD cannot be as efficient as real Hardware Ram Disks, due to wear leveling and other limitations in comparison are slower and less secure.
Even though ram banks loose data as soon as electricity is cut off with the new hardware ram disk SATA controllers this problem is eliminated with simple battery backup and external power supply, furthermore the content of the whole disk can be dumped in an image onto an integrated compact flash disk and replaced on ram disk when needed.
The very big novelty about hardware ram disks is that are bootable so the OS can be installed on it.
There were some intermediate approaches to this problem using a PCI slot card controlling ram banks to create a ram disk seen by the OS as a regular HD, those systems were not bootable and extremely expensive, such as few thousands of dollars, but now all of this got to an end.
Today the main and more ancient bottleneck in a PC is the traditional HD, and does not matter if it is the fast 15000 RPM SATA II or SAS last technology plenty of cache and smart tricks to boost performances, this kind of HD today are appreciated as traditionally reliable and very large storage systems, are also extremely fast if compared with past models, but when speaking of speed and fast computing they result to be just obsolete.
If in need of boosting the PC today is possible to adopt a brand new SATA real ram disk, the ultimate bottleneck remover, able to boost performances of a ordinary PC to levels which are beyond any comparison with a regular electromechanical disk based home PC.
Imagine to have your PC booting up in matter of few seconds and responding to you almost in real time, wouldn't it be great?.
When launching data crushing and memory consuming applications, especially when swap and caches are needed, with bootable real ram disk the PC will deeply surprise you as it will be looking alike a rocket instead of the usual tickle tickle grinder we are used at.
In conclusion, if you want a fast PC today you can opt for a real ram hard disk investing a reasonable amount of money, supercomputing is here and available to the masses.
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