Wednesday, January 19, 2011

Memory Lane

In case you were wondering what all this fuss is about SSD (Solid State Drives) is about, the basics of how your computer stores information is needed.

A computer hard drive is where all your information, programs, pictures, music, software, and other things are stored.  Think of it like a warehouse.

Up until recently, these are commonly spinning disks.  Much like a music record (vinyl).  With a controller arm (like the needle of a record player).  Just like a record player, a hard drive is sensitive to physical shock, bumps, jolts, drops, etc... specially when in use, like when you're playing a video, music, or using a program.

If the hard drive is spinning and you hit, bump, or drop your computer, the controller arm may hit the spinning disk and damage data, and most likely the physical disk as well.  Like a needle scratching a record if hit during playback.

Over the years, hard drive manufacturers have added special systems that can detect if the disk is falling and moves the controller arm away from the spinning disk to prevent any physical damage.  Think of it like an airbag or parachute for the hard drive.  But this is still a mechanical system, subject to physical damage and failure.

Enter the SSD, or Solid State Drive.  These are memory chips that replace the spinning platter and moving parts of a traditional hard drive.  The technology of SSD is not new, but only recently has it been made affordable (well, that's relative) to the general public.

Essentially, modern day computers are built around economic compromise.  You may notice that computer ads boast about several types of memory (Cache, RAM, HDD, VRAM, etc)  Some numbers are smaller (KB, MB) and others larger (GB, TB).  The reason for having so many types of memory is simply cost.

If the whole computer ran on the best, and fastest type of memory available, computers would cost several thousands of US$ more than they do today.

Each type of memory decreases in speed and cost... the slower the memory, the lower the price and more storage can be given to the consumer.  Current hard drives can hold 1000x more data than   So cost for current hard drives was 1/1000 of previous memory chips.  With the introduction of SSDs, that gap has been decreased to about 1/20.  Still way more expensive than traditional hard drives, but offer a significant speed increase in system performance.

What computer manufacturers don't tell you is that usually, the reason you 'old' laptop feels slower than a model that is just a few months newer, is usually just a few upgrades that can be done to bring your aging laptop to a respectable speed once again.  It won't make up for newer technologies, but it will make laptops that are a few years old, usable again and practical to keep.

My upcoming entry will be on upgrading and updating my trusty IBM Thinkpad X31 to as close to modern specs as possible.  This means 2 simple hardware upgrades: maximum RAM, and an SSD upgrade.  That's coming up tomorrow!


  1. i read somewhere that using SSDs will actually make the read/write process much more faster than HDD. but the downside is, they are more prone to electrical damage, i.e., electrical shocks (talk about Philippine electrical system and all those brownouts).

  2. Hi Roberto, yes they are more sensitive to electrical damage than regular HDD. But no more than the rest of the computer. So if it will damage the SSD, most likely it will damage other parts of the computer as well.

    The real-world benefits for laptops far outweigh the disadvantages. Mainly because laptops and mobile computers are subject to physical shock more than electrical surges.

    You're more likely to damage your laptop by using it while the disk is spinning, rather than a power spike.

  3. come to think of it, you are indeed right. i have totally forgotten that lappys got an AC adapter which charge the batteries, and also serves as 'voltage regulators'. i was thinking more of the SSDs for a big desktops :p

  4. For desktops, there's a new crop of hybrid hard drives than offer much higher cache and can preload common programs into a smaller SSD bank. Desktops have a much larger RAM capacity than laptops so the performance jump won't be an noticeable. Hybrid drives offer a good compromise between capacity and speed. They have them for laptops too btw, but you lose out on the power saving benefits of a full SSD.


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