NAND memory characteristics

[idata]

There were 2 references to the characteristics of NAND memories as used in SSDs as I watched the online videos of the new SSD drive with a 500Mb/sec transfer. The first reference was to the need to run a program (recommended daily) to keep the access speed up, on the SSD drive. Regarding this point, is this the equivalent of a defrag program for a mechanical drive, where there are holes as files are read and written, and this puts them back together again and maybe even optimizes the written space and the blank space?

Secondly, there is the mention of backing up the drive because of the limitation of how many times a NAND can be written-to or read, before it starts going bad. What exactly is this limitation? How does it occur? Is this the identical to the failure rate of any solid state DIMM memory carded into the computer memory slots, based on mean-time-to-failure, or is something else going on here?

A third question, not covered in the videos is,"Is this non-volatile memory, or is the memory held alive by an onboard supercap or other voltage source?

[idata]

Than you. It is just this type of frankness of the current recordable media state-of-the-art that is needed for risk management for an archive that either is universally important to keep, or a personal archive that is important - if nowhere else - in the mind of the archivist, to keep. You simply have to weigh the risks versus importance of the data to develop a system of successive regeneration of the data on same or current media (down the road). Even then, you have to wait for the 'big boys' to battle it out to see who's left standing as to the standard for the new media that emerges as the latest/greatest.

[idata]

The program that you mentioned is probably the Intel SSD Optimizer, which is part of the Intel SSD Toolbox. It is recommended for use once a week. The optimizer is most useful with OSs that do not natively support the TRIM command, such as XP and Vista, but is good insurance when used with OSs that support TRIM, such as Windows 7. The SSD Optimizer performs the same function as the TRIM command, but done manually by the user.

The TRIM command, or really it's function, is not a fix for SSDs, but simply a function that SSDs need to perform at their optimum level over time. OSs have been written with the needs of HDDs in mind, but SSDs function differently and OSs are only recently taking their needs into account. For example, SSDs do not have sectors, cylinders, or tracks as HDDs do, so that model of a storage device does not apply to SSDs. SSDs do not need de-fragmentation as HDDs do, and de-fragmenting an SSD actually has a negative affect on it. I'm sure that in the future we will see the file systems of OSs change to fit the way SSDs function, which will likely add to their performance.

[idata]

I remember telling my friends years ago that someday data would be stored in a solid crystalline block with the data written along the crystal faces, and read holographically from each axis that could produce a face in that crystalline structure. Back then, hard drives spun slower, and had less memory than a 2Gig memory stick. I still have to lament so short a storage life in today's media, without drastic intervention by rewriting to new media. The memory leveling reminds me of early television when they still used videcon tubes. They engineered the cameras so that the scan dithered ever so slightly just so that if you had a bright spot in the picture it wouldn't prematurely age the phosphor it hit in one spot, which, otherwise eventually led to a 'burn' or black dot in the picture where the phosphor had been damaged. A lot of local stations, in order to save money , would continue to run these cameras with damaged tubes, hoping it wouldn't be noticed, until either the damage started becoming too great, or they accumulated the money to take the camera offline and replace and realign the tube. Back them, before widespread cable-TV, the rabbit ears and shadows from reception's multipath ghosting was more objectionable than some little dot, anyway.