What is an SSD?

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A solid-state drive (SSD), also called a flash drive, is type of hard drive. Though the architecture of an SSD is quite different from traditional hard drives, the name is carried over. An SSD utilizes a special kind of memory chip with erasable, writeable cells that can hold data even when powered off. It might help to think of an SSD as the larger cousin of the memory stick.

Like standard drives, an SSD utilizes a special area for cache memory. Cache memory serves the function of increasing processing speeds by holding data that is needed repeatedly. With the data close at hand in the cache, it does not need to be fetched from the main storage area each time it’s called.

Some SSDs use cache that is volatile, as in synchronous dynamic random access memory (SDRAM), while others use non-volatile cache. The former requires a power source to retain data, just like computer RAM. The latter type retains data even without power.

An SSD has many advantages over a traditional drive. Seek time is decreased significantly, making the SSD very fast. Being solid-state, the drive has no moving parts to malfunction, and does not generate significant heat. It is also lighter than a standard drive, more power efficient, and completely silent. Finally, the SSD is more durable. If dropped or banged it isn't as likely to be damaged.


There are, however, disadvantages to an SSD over a standard hard drive. Most SSDs have a slower write time than standard drives, although this can vary, depending on the type of flash memory used and number of chips. Standard drives are also relatively less expensive than SSDs, although the price has fallen. The SSD also has a limited life expectancy of erase/write cycles, after which it no longer performs reliably. A hard disk may be able to deliver a good ten years of solid operation.

Many people in the field believe that flash drives or SSDs will eventually replace traditional hard drive technology. By the time this happens, the disadvantages will likely have been eliminated or significantly mitigated. Even today, an SSD can extend the life of a notebook battery, decrease the weight of the machine, make it quieter, and increase read performance.


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Post 12

Can you put an SSD into any laptop? Will I be able to play the newest games?

Post 11

One question. How would you know if your netbook has ssd? I am trying to defrag mine and you can't defrag if you have ssd, right?

Post 8

While true that flash takes longer to write than magnetic disk storage, it is not at all true that SSDs take longer to write than HDDs (hard disk drives). This is because they utilize multiple flash chips arranged on multiple access channels that are accessed in parallel which, along with complex data management systems to spread the data across the available chips and to access the chips through multiple channels simultaneously gives them far greater performance than a single chip alone and, cumulatively, far greater performance than any HDD. As an analogy, a horse can run 100 feet much faster than a man, but 100 men running at the same time can each run a foot faster than a horse

can run 100 feet, and 1200 men can each run an inch far, far faster than that poor horse can run that 100 feet. Each chip may be slower than a spinning magnetic platter, but eight, sixteen, or thirty-two all accessing pieces of the desired data at the same time are cumulatively far faster than even the fastest HDDs can manage. As an example, the OCZ Agility 2 that I have as my system drive can read/write at 285/275 MB/s, while the Western Digital Scorpio Black that it replaced, one of if not the fastest 2.5" hard drive available at the time of this posting, is rated at 108/108. HDDs also suffer very poor latency due to the required physical movement of the heads to the tracks where the data is, while where on the chips in an SSD the data is is irrelevant and their latency is thousands of times lower than HDDs. Thousands. Taken all together this means that an SSD can access, read, and write data far faster than an HDD. They also shine in random IOPS (input/output per second), which is the kinds of very small but fast data reads and writes that databases and other applications perform on servers and operating systems often perform on home computers (most often as swap files), where they can be dozens to hundreds of times faster than HDDs. SSDs are also silent, more physically durable (since they have no moving parts, and are thus more resistant to damage from impacts), use much less power, and operate at a much lower temperature than HDDs, saving you on your electric bill and making your computer quieter and cooler at the same time.

The most commonly stated, and misunderstood, fundamental drawback to SSDs is their allegedly poor longevity. It is true that each cell can only be written to a certain number of times--depending on the type and quality of chip it can vary from 10,000 to hundreds of thousands of writes. However, thanks partly to ever increasing quality of flash chips and partly to ever improving wear-leveling technology in the controller chips this is not the deal breaker the uninformed make it out to be. "Wear leveling" is the catchall term for a variety of techniques that different SSD controller makers use to spread the writes evenly across all cells, so that no cell or group of cells wears out quickly but all do gradually wear out together, and as individual cells do begin to wear out it is recognized by the controller and the data on them is replaced with data that has been only read in the past, to reduce the chance for further writes. In real life this amounts to good consumer grade SSDs having longer MTBFs (mean times between failure, the industry term for expected average lifespan) than HDDs. That's right, kids, LONGER expected lifespans. My OCZ Agility 2, for instance, has an MTBF of 2 million hours, while the Western Digital Scorpio Black it replaced has an MTBF of 1 million hours.

To sum up, while you do have to do some research to find which SSDs are worth the much higher cost compared to HDDs (I recommend Intel's X-25M or OCZ's Agility 2 or Vertex 2 as of this posting), they read faster, write faster, access faster, use less power, are quieter, are more durable, and last longer than hard drives. The only two real drawbacks are cost and size. SSDs are much more expensive than HDDs, and tend to be much smaller to keep costs down. I recommend using both. Use an SSD for the system drive, with the operating system and applications that can benefit from the performance boost of an SSD, and a large HDD for media storage, which doesn't see much of a benefit if any. In my personal system I use a 50 GB SSD for the operating system and applications and 4 1 TB drives in a Drobo connected by Firewire 800 for media storage, a 250 GB HDD in a USB2 enclosure for system drive backup, a 1 TB HDD in another USB2 enclosure for additional storage, and a 16 GB flash drive for file transfers between non-networked systems.

Post 7

Do your homework: 64MB of cache, Slighted read/write time, and better technology to come = Must Have! Two Raid0 30GB SSD HDDs by OCZ have been my single (or double) best purchases for my PC!

The only bottleneck on any PC built it the last four years, is Write/Seek times on a Plattered HDD. No matter the RPMs on the drive, 16-32MB of cache memory means you're always looking for something. Plus, have you ever sat two feet away from two 15,000 RPM HDD's!

Post 6

Is it possible to utilize an SSD and HDD? SSD for main PC use. And HDD for storing files? Also the video I just watched said the Samsung SSD is Java based. Would Java be a "security Risk" in that sort of environment?

Post 5

To anon 33168: There are many different types of SSD flash drives with varying architectures, and according to info, one type is faster than HDs, but most are indeed slower at writing, (but faster at seeking/reading). It's because of the way flash memory works.

As for a shorter life, flash memory has a limited number of read/write cycles before it becomes unstable, whereas a platter drive can last for years. It does not have a limit as to read/write cycles, but because it has moving parts, one of those parts eventually fails if you use the drive long enough. But 10 years is a long time, and many drives last twice that long until you replace them

simply to get newer, faster technology.

No one can say what the average life of a flash drive is, because it depends on how much it's used, since its read/write cycles are limited. Two people could buy the same exact drive, and have it last a vastly different amount of time, depending on use. However, there should be enough read/write cycles that most people will probably end up replacing the technology with better technology before it fails. IOW, whatever your SSD is in, you won't have it forever. You'll upgrade it, and whatever you upgrade to will have a newer, better, faster, SSD.

Post 4

So the main disadvantages are:

*Less space for more money (under 100GB costs over $100 in SDD, while 1TB of regular HDD is $90 as of today)

*It takes longer to write.

*It has a shorter life time.

What do you mean by write? Like, when you save a word document, it takes longer? and how much shorter is the life time? Is it determined by the model you buy? How can you tell what it is? What's the average use(like you said regular HDDs are about 10 years)?

Post 3

No, it is likely b/c these little netbooks with SSDs and Linux have small amounts of RAM. Linux does not require as much RAM as XP (and XP requires half as much as Vista). If you read minimum requirements for XP, I think they list something ridiculously small like 256MB, but in reality if you want the computer to work fast and efficiently enough that RAM is not a bottleneck, 2GB RAM is needed. So your netbook is having to create a large swap drive on the SSD, which is probably small to begin with (some SSDs are a mere 8GB). If you want XP on a netbook, you should really buy one with XP already on it, b

/c they come with more RAM and more hard drive space. That's why the Linux models are cheaper -- less RAM and less drive space = less money. But you're better off sticking with Linux if that's the case. Linux will run better on it.
Post 2

My acer aspire one doesn't have a standard hard drive. It has SSD on it. The operating system of my netbook is Linux. The problem is when I convert it to windows XP it become slower. Is it because it has SSD not a standard hard drive?

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