Solid state drives, RAM, ROM, Q & A

[Still_Learning]

What is so different about Solid state drives? I know they are quicker then the others, more expensive and ussually smaller, but have not owned one on a PC yet and dont know too much about them..

Also what is the difference of ROM and RAM, I know Rom is read only memory (also a old school comic book character) so is that pretty much where the BIOS is stored and where, in the CMOS powered by the CMOS battery? Ram - read access memory can pretty much read and write to it instead of only reading correct? but Ram is not stored for a long period of time like Hard drives, is this correct or no? thanks

[DNR]

hey guy, its good to ask questions, so keep it up.

ROM, Read Only Memory, is used for the bare instructions needed to boot your computer up - it holds your instructions - as long as the CMOS battery is alive...

RAM, Random Access Memory, is not meant to hold data after you shut down your box, thats why its called Random. The RAM is the playing field of where all your applications and OS play together - the more RAM you have, the more room to play comfortably, nicely.
Some forensics experts have recovered data left over from the last time the computer was used. It is just not meant to store data when the computer powers down.

SS HDD? Expensive, but like any electronics, the prices get better. SSHDD is nice for tough environments. The only Personal Opinion I have is it might be susceptible to the same defects found in USB memory chips - lost data, inexplicable failures. SS HDD were actually smaller chips meant to hold a little bit of data - like those cheap handheld-keychain voice recorders/reminders. They held enough for about 5 or ten minutes of voice recording, if it failed - it was a cheap product anyways. Flash drives are more associated with cameras and more expensive recorders. They are meant to keep the data even without power - you can remove a SS-SD from a camera and put it in your computer - without losing the data. Now, they got the size, and reliability high enough to try it in laptops. You'll have to read up on those yourself to get more specific.

DNR

[Still_Learning]

(random access memory, not read access memory *smacks self in forehead*)

so the SSD HDD is pretty simular to a usb thumb / flash drive but just on a bigger scale that fits in the laptop? (Like the smaller Asus EEE laptops with like a 8GB SSDHDD) I will read up on this more, (the advantages of this over a SATA2 and such) thanks

[lilrofl]

This is a big question, but I'll try to keep it short

SSD vs. HDD
There are many types of solid state drives, the important variable in todays market is if the drive is a SLC (single layer chip) or and MLC (multi layered chip)

The differences are that information is stored in one layer on a single layered chip, and multiple layers of information is stored on multilayered chips (self explanitory you think?) The important difference is SLC drives hold LESS information but access it faster.

SSD has faster read times (note write times very largely depending on whether you have an MLC or an SLC SSD) too many acronyms? SLC drives write very fast while MLC drives are no better then platter drives in this regard.

SSD has no moving parts, this is a big plus for laptops because they are almost immune to drop damage. No moving parts also means less power consumption, no noise and very little heat generation.

SSD never fragments, in fact defragmenting and SSD is stoopid and ill-informed (more on this later)

Now for the disadvantage, aside from the small storage capacity (that's obvious I think) is limited write cycles. This means that SSD memory cells will wear out with use, 1000 - 10,000 cycles for MLC drives and almost 10 times more for SLC drives. What this means is that you can wear them out faster then HDD's. Over the last few years companies have designed a system called wear leveling which spreads usage over the entire disk evenly, extending the life of the drive.

End state:
SSD is awesome for laptops and those cute little netbooks, they just don't stand up to the reliability or storage capacity when we're talking about desktops. I have a 64GB SSD in a laptop and I love it, battery last longer and no heat no noise, read/write speeds are incredible and boot times are almost nonexistant... but for my desktop... I'll go for something a bit bigger, and the 10,000 RPM of the WD VelociRaptor... well...

SSD is just another tool, and you have to choose the right tool for the right job.

Cheers =)

[Still_Learning]

lilrofl,

Thanks for the detailed explaination, i learned alot from reading that. awesome post

[DNR]

nice thread keep it going

More on increasing endurance in SSD....

Rotating hard disk drives employ Self Monitoring and Reporting Technology (SMART), which was designed to act as an early warning system for pending problems with mechanical media. Though this technology is useful for monitoring wear on rotating hard disk drives, it cannot be used to monitor the useful life of a solid-state drive. Since solid-state storage products have no moving parts many of the parameters monitored by the SMART function are not applicable.

Solid-state storage components, which are the fundamental building blocks of every solid-state drive, can lose the ability to retain programmed data after hundreds of thousands to millions of write/erase cycles. With no method to determine or predict when write/erase cycle endurance will be exceeded, a solid-state storage product is typically allowed to operate until it ultimately fails, leading to unscheduled system down times and significant data loss.

It is important to note that endurance is not a function of the storage media. Storage media has its levels of expendability - how long a SSD will last depends on the combination of the storage media and the controller technology used to store the data.

Write/erase cycle endurance for solid-state storage is specified in many ways by many different vendors. Some specify the endurance at the physical block level, while others specify at the logical block level. Some define it as read/write capability, others consider data retention.

Endurance of a SSD will depend on three things:

Storage Media/Medium

Wear-Leveling Algorithms
Wear leveling is important as it allows data writes to be evenly distributed over the entire storage device. A device with no wear leveling wears out faster because data is written to the same physical block.

*static wear leveling - only concerned with maintaining stored data areas
*dynamic wear leveling - only controls active or dynamic areas of memory

Error Correction Capabilities (ECC tech)
Each manufacture has their own codes to perform ECC. Lines of code determine how the device will check each bit for errors, it also can tell it how to deal with the errors. Just like different levels of quality, some ECC are smarter than others.

What makes one SSD technology or manufacture different or 'better' than the other depends on how they combine or focus on those three things, Storage Media/Medium, Wear-Leveling Algorithm, Error Correction Capabilities. Each SSD maker can have various levels of prices and dependability based on its mix, maybe a cheaper SSD will have Error Correction, but no real Wear-leveling tech. Maybe one will use a cheaper SSD medium- prone to age, but build on great wear-leveling technology.

Even though the write endurance rating for BiTMICRO’s computations is smaller (1 million cycles), endurance ratings are much higher as a result of wear leveling methods, proprietary RS ECC and other techniques designed to prolong the life of E-Disk SSDs. Assuming a much smaller endurance rating of 100,000 cycles (typical rating quoted by NAND flash vendors), a bigger volume of writes per day at 3.4TB and no caching nor wear leveling implementations, a 160GB SSD is projected to last up to 12.9 years, which is definitely longer than the average life cycle of most IT storage devices and equipment.



------------
other errata

non-volatile storage systems that do not lose their data when the power is turned off. The dominant technology for non-volatile solid-state storage is NAND flash. While NOR flash is also a possible solution, implementation of NOR technology is generally confined to cell phone and other chip-on-board applications. For these applications, NOR provides execute-in-place, boot and data storage functionality in a single chip. The economies of scale and component densities of NAND relative to NOR make NAND the ideal solution for non-volatile solid-state storage systems.

The two dominant NAND technologies available today are SLC (single-level cell, sometimes called binary) and MLC (multi-level cell). SLC technology stores one bit per cell and MLC stores two bits.

SLC NAND is generally specified at 100,000 write/erase cycles per block with 1-bit ECC. MLC is generally specified at 10,000 cycles with ECC. Therefore, when using the same controller, a storage device using SLC will have an endurance value roughly 10 times that of a similar MLC-based product.
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https://www.amazines.com/Error_correcti ... lated.html
https://www.amazines.com/article_detail ... eid=250071
http://www.storagesearch.com/siliconsys-art1.html

DNR

[Still_Learning]

So without opening my drives and screwing them up, this is what the insides look like, the top one being a IDE, SATA or SATA2, and the bottom drive being the guts of a Solid State drive

[lilrofl]

Actually that is exactly what they would look like lol. Above that, great description of SLC/MLC differences!

I thought of another important factor when considering an SSD over and HDD, file system. Journaling file systems like XFS (linux) improve the life of SSD's because they minimize writes per action with a cue.

When deciding to try out an SSD in my laptop I also decided to run Linux (I chose Mandriva having had previous Mandrake experience) using XFS. The limitation of storage capacity was worked around with a 500GB portable HDD.

Obviously the biggest concern about SSD's is, "When is this crap gonna crash and loose all my data?" There are a lot of googlable formulas expressing this concern, but with wear leveling, and newer tech the number is getting to the reasonable stages I think.

My SDD is rated at 60 years if I write the disk 100GB per day, since the capacity of the drive is a paltry 128GB the likelihood of me accomplishing such a feat is just silly. As for the boost in performance from the SSD, from boot time to AV checks, I like it very much. Again, I'm not ready to slam one in my desktop as a primary storage media... the cost just does not justify the performance boost IMO (yet)

[Still_Learning]

So you can run 100GB a day for 60 years on a Solid state drive, before it goes out? Really? That is incrediable. how many years would a western digital 500GB or 1TB internal 7200RPM SATA2 drive go for before it dies out? (or one set up with raid / double drives?) Comparing the equal amount = 100GB per a day used method?

Inquiring minds want to know.. or maybe just one registered inquiring mind

Edit:: and Yes! DNR you went way overboard on the information, but that is what I like. All that knowledge is great. I may not use it right this second but tommarow may reference some of it. Once again another great post. That post actully pushed my learning to the next lvl of solid state drives.

[floodhound2]

Sorry but I have not read anything posted regarding any negative sides of a solid state storage device.

One thing that comes to mind is the way data is stored. It is not as efficient as a standard hard disk. This meaning a regular hard disk may store up to a say 1000 mp3's in 40-Gigs and the solid state may store only 200Mp3s in the same 40-Gigs.

Another is cost. A 1-TB SATA hard disk is under $100 compared to a 250GB solid state for well over $400.00

The solid state storage devices still have a way to go in order to dominate the current hard drives.

Just my 2 cents!

[Still_Learning]

Whatever happened to holographic drives? I remember hearing about them and how much data they were suppose to hold

Why is this..?

"One thing that comes to mind is the way data is stored. It is not as efficient as a standard hard disk. This meaning a regular hard disk may store up to a say 1000 mp3's in 40-Gigs and the solid state may store only 200Mp3s in the same 40-Gigs."

Why would a "regular" HD hold 1000 mp3's, i know for a fact MP3 which are ussually 4 to 7MB each, or WAV files being the best quality which are alot larger file size due to quality (usually 50 to 100MB per a track). I am curious as to why the same 40GB drive on a Solid state hard drive would only hold 200 as opposed to the IDE, SATA holding so , so much more, since the file size is the same both. The MP3's file size does not change unless you edit it. How could it be double the size on one drive and not the other..?

also btw; Floodhoundz, I did see that info posted above please re-read, their was a nice explaination of why each one is better and why, and thanks for the electronics tut that you posted earlier, i am sure i will have many questions for you later on

[floodhound2]

The reason is in the way that the data is stored on the devices. Solid state devices use rows and columns that are given a specific size by the architect. Say one row is 64 bits long. Well if you only need to store 1 bit, then the whole row is chewed up. Now multiply this by the 1000's and you could envision the "holes" of data missing. Imagine a row being 256bits long and you only need to store 1 bit. You get the idea.

Where a standard hard disk is done entirely different.

[DNR]

There is no such thing as informational overkill, as long as its good nfo

Excellent point floodie, since I am in a hurry I can only "suggest" that I did find nfo regarding just that issue - the size of the 'cells' mismatching to the data bits. Remember- there is no 'defrag' on a SSD, so those holes will never get filled.

Now, people say you cannot predict when a SSD will fail - why not install a counter, either counting r/w cycles, or hours - an countdown when 1,000,000th cycle is set to expire. The admin can choose to use the expired SSD at their own risk, or transfer important data over to a new SSD.

As far as r/w cycles on regualr HDD - go look it up. They have been around for years, so everyone can assume they can last for 5-? years. I have five HDDs, two are ten years old - and they still work. As long as the quality of workmanship and smart programming is there - SSD can last just as long.

If I had to buy a drive, I might get a SSD - as an external device. Firewire tech.

I think society has to get over their comfort of seeing mechanical parts - I know I don't like "blackbox" technology. (blackbox tech is tech that is hidden from inspection) How would guys like to open their car hoods to see a big black box sheilding the engine from view? The SSD has no moving parts - so how can the quality of workmanship be observed? The code to handle your data might be propriety and hidden from your inspection - does that make you nervous?

Good thread brainiacs

DNR