Solvently State disk

the term solidstate disk or often still English solvently State disk designates a storage medium, which is composed of memory chips only and can non removable disk-like be addressed.

Table of contents

of advantages

the renouncement of any mechanical parts leads compared with normal disk memories to an enormous gain in speed. At the same time those are solvently State disks frequently many smaller and easier than non removable disks; the employment in mobile devices becomes thereby at all only possible.

operational areas

by the short access times and high transfer services of solvently State disks are suitable these memory systems particularly for applications, those very diskannoyingly work (data bases, sort's applications). Gladly these disks are used also by developers and testers, in order the efficiency of hard disk controllers and - penalties to measure.

Apart from these typical applications of PCs there are applications within the range of the Embedded of system also, with which it depends exclusive on the renouncement on the mechanical parts. A 1-Chip-Mikrocontrolleranwendung does not have frequently for place and current consumption reasons only at all a non removable disk connection.

Further areas of application are in very electronics-hostile environments, in which dirt, mechanical vibrations, ambient pressure fluctuations, temperature and magnetic fields (space travel) prevent the employment of mechanical plates.

SSDs in the mass-market

by speed increase and price purge of the Flashspeicher is to be counted on the fact that they - primarily with mobile devices - supplement and even replace the conventional non removable disk technology in the next years. First is to happen with hybrid non removable disks (approximately starting from 2007). Here a conventional non removable disk with few gigabyte Flashspeicher is combined. The latter functions as buffer. Differently than conventional non removable disk buffers (Cache) this keeps its data also after switching off and is largely enough to keep the usually-used files. Thus the actual non removable disk is started only if necessary - thus threatening “overflow” -. Such a drive assembly thereby will in most cases function loudless and currentsaving (0.1 to 0.5 W). The coming Windows Vista promises to optimize non removable disk accesses to these drive assemblies (prototype and Microsoft message).

Already in production are pure Flash drive assemblies. These were military and other few preissensitiven markets reserved. Since March 2006 the electronics company Samsung manufactures however a model, which might ring in a strong price purge. Goal market are Notebooks with 2.5 - and 1,8 tariff non removable disks. The drive assembly in the smaller two crest factors seizes 32 gigabyte, which it can pick out with 52MB/s and describe 32MB/s. In peace it consumes 0,1; during accesses a half Watt. That would be a third to fifths of conventional drive assemblies of that measure. Also the weight reduces by three quarters to 15g. The price is assumed with 500$. In the current year are 500,000 units produced; 2008 their successors in 30 per cent of all Notebooks to find its.

Unclear is however, which life span one may expect from of Samsung new Flash disk. In the specification of the used NAND Flashspeicher chips one finds “Program/Erase of cycles: 100.000 ", whereby this value refers to a memory cell. Such a value would be sufficient when “occasional” use the memory chip, approximately in a USB stick, more than, with which read/writeintensive non removable disk enterprise might it against it a quite short life span of the storage medium mean.

See also SSDs in the comparison.

surrounding field

within the data base range gladly “usual” non removable disks are replaced through solvently to State disks, if with the time the requirements rise to the speed. Here the renouncement of mechanical parts becomes particularly apparent with the access time. Since here besides with relatively small files one works frequently intensively, these fit also well the usual capacities of solvently State plates.

In the video range solvently State disks are used today more rarely, since there very large capacities are needed. In this case the use of RAID Plattentürmen is often a more economical alternative with similar efficiency.


State disks seem to technology today in a multiplicity of variants. Speed and longevity are common to all opposite mechanical non removable disks.

Between 1980 and 2000 dominated the memory systems, which made direct substitution of a non removable disk by one solvently for State possible disk. With the arising of the Flash memory (EEPROMs) those penetrate solvently State disks since the turn of the century strengthened also into the Consumer range.

In the meantime one finds organized storage media “non removable disk-like” as USB sticks at the PC, into mobile MP3-Playern, in addition, as storage media for digital cameras.

The special preference/advantage of Flash memory lies in the fact that they can keep their contents also in case of a loss of supply voltage. This advantage one acquires with the disadvantage that the number of recording procedures is limited. Frequently also the scanning rates of Flash based solvently State disks are not as high as with are based.

Some manufacturers try to connect the speed of RAM memories with the data receipt of other storage types by it z. B. a conventional non removable disk also into the housing integrate. Here the circle closes: on side the conventional non removable disks with ever more RAM than buffers and on the other side solvently the State disks with mechanical Backup.

solvently State disks in the comparison

in the following are at present current procedures for the comparison specified.

DRAM disk CompactFlash map Flash disk RAM disk non removable disk
5.25 ″ or PCI - map by ATA - adapter 3.5 ″/2.5 ″/1.8 ″ as part of the main memory to the comparison; 3,5 ″ S-ATA
sizes 1 to 16 GB 0.1 to 12 GB 4 to 175 GB 0 to 4 GB 100 to 500 GB
cost per GB 60 to 180 € 60 to 75 € starting from 55 € starting from 80 € starting from 0,40 €
composition drive assembly of 200 to 700 €
adapters 7 to 20 €
+ map
- - -
port P-ATA
on motherboard fastens P-ATA
90 to 125 MB/s
90 to 125 MB/s
10 to 22 MB/s
9 to 19 MB/s
57 MB/s
32 MB/s
700 MB/s
700 MB/s
50 to 75 MB/s
50 to 75 MB/s
access reading
access writing
0.05 ms
0.05 ms
0.8 ms
10 to 35 ms
0,02 ms
0.02 ms
0.04 ms
0.04 ms
9 to 14 ms
9 to 14 ms
overwritable arbitrarily 1 to 2 million time up to 5 million time arbitrarily arbitrarily
storable with −25 to 85°C
(DRAM modules)
−40 to 85°C
−55 to 95°C
−25 to 85°C −40 to 70°C
shockproof - enterprise
shockproof - storage
2000 G
2000 G
1500 G
1500 G
60 G
350 G
behavior when PC switching off consistently
by Standbystrom
problem-free problem-free overrun;
some software secures on non removable disk
behavior with power failure for 3 to 16h consistently
by Akku
problem-free problem-free overrun problem-free
sound lot
without further drivers usable no
test report gigabyte i-RAM
HyperOs hyperdrive III
general, from 2000
Sandisk of extremes III
- - example
offerer gigabyte
RAM disk
manufacturer remarks speed by P-ATA/S-ATA - connection on motherboard. With distance most favorable SSD. Only adapters starting from 2004 support DMA (direct memory access). A Cache minimizes the write access time ggü. CompactFlash. Size dependent on motherboard and operating system.

The lower price borders refer in the larger models, which are comparably favorable with all SSD procedures per gigabyte, however absolutely regarded very different prices have.

With operating system, program starts and where always access times play a role, these are solvently superior to State procedure the non removable disks. Principle-caused they succeed in keeping the above speeds upright with coincidentally distributed accesses.

For the CompactFlash variant a further application possibility results. Owing to adapters, which are fastened as Slotblende, the CF-map can be exchanged from the outside - the wiring remains in the housing. Since the adapter in addition neither PCI - nor other contact strips has, it can be inserted completely after available space. That is a Unikum of these solvently State variant and made possible like that applications to separate users or operating systems cleanly and surely from each other. Because so each user can bring along its preferential operating system and working environment, whereby he at the same time leaves no data in the PC, since he carries the “non removable disk forward” simply. Additionally CompactFlash maps are many more durable and handier than their “ancestors”, the non removable disks in the quick change picture frame.


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