Notebook Technology : Solid State Hard drives

A survey conducted sometime last year revealed that notebook computers accounted for more than 50% of sales for computer manufacturers. Desktops were overthrown for the first time and laptops became common place.

There are two main reasons for this mass adoption:
1) People find it convenient to use a portable rather than sit in front of a clunky desktop.
2) Competition in this space and advent of new technology has crashed prices making notebooks more appealing and affordable.

Upcoming technologies for portable computers will make computing in notebooks more appealing than it is now and this will eventually lead to increased market adoption.

The first of these technologies that I will talk about is the Solid State Drives (SSD). SSD have been around for a very long time now and many of us have used it as a part of our daily computing experiences. Some of us are glad to have this technology eventually replace the dreaded and unreliable floppy diskette. I am talking about the USB Flash drives aka USB Memory keys aka Thumbdrives aka USB Pen drives. All that these miniature devices contain is a chip or two that provide space to store data. Not only are they small and reliable they are also independant unlike floppies which need a separate drive in the computer to work.

A modern day computer has only one permanently attached mechanical device: The hard drive. Still very similar in its technicalities to the first one ever invented, data on this device is stored on the surface of a magnetized platter which is made to spin all the while the computer is powered on. And a spinning device implies the presence of a motor that is constantly running and consuming power. An average hard drive consumes about 9W of power for an 8 hour usage and accounts for 7 to 15 minutes loss in productivity per day due to its slow speeed.

The magnetic platter based hard drive (MHDD) has been the single biggest technology bottleneck in modern computers simply because we have seen significant changes in all other electronic components that go on to build a computer. Every device other than the hard drive is bottlenecked by the hard drive's inability to deliver data at a faster rate compared to the other devices. The reason for this relative lack of growth in hard drive technology arises from the higher cost of new technologies trying to replace the MHDDs thereby killing adoption. It is simply difficult to beat the cost per GB (GigaByte) that a hard drive provides while at the same time providing the best possible data transfer rates.

I recently purchased a 250 GB hard drive for 3500 rupees. That would be around Rs. 14/GB. Compare this with the cost of a floppy which costs around Rs. 14 for a 1.44 MB disk and this excludes drive cost. A Blank DVD of 4.4 GB (true storage space) costs around Rs.30 which is about Rs. 7/GB. However a DVD is a read only media and the rewritable versions are more expensive, extremely slow compared to hard drives, and have to undergo a painful burn process to achieve data writes.

Then we saw the influx of USB memory keys in the market. At the time of this writing a 4GB Flash memory key costs Rs. 3000. That is Rs. 750 per GB. Inspite of this price barrier the technology has caught on and is commonly used for data transfers between computers. This is mainly driven by the convenience of using the device.

Technically, Solid state drives that use mostly what is called as NAND Flash chips provide very high read speeds compared to hard drives. But these chips are not available in huge capacities to be able to replace hard drives. While we now have hard drives in the market that have 1 Terabyte storage, we are still counting in tens of GBs for flash drives.

However all this is about to change. The biggest selling factor of solid state devices as replacement for hard drives is the lack of mechanical parts. What this simply means is that if you drop a notebook computer having a solid state hard drive, the chances of you losing data in the hard drive is very very less. There is no scenario of the read-write head in the magnetic hard drive scratching the platter and data being lost. There are no moving parts. All data is stored on silicon chips which are designed to withstand shocks. Also because there are no motors the power consumption is dramatically reduced. A SSD uses 200 milliwatts during read/writes, and 0 watts when not being accessed. This amounts to signifant savings in power consumption especially in notebooks. As silicon chip manufacturing technologies improve, manufacturers are able to cram in more and more data into a given real-estate size of a semiconductor chip.

At the Consumer Electronics Show last week, PQI announced their 2.5" 64 GB Solid State Hard drives capable of doing 100 MB/sec data transfer rates. While this may sound a lot less than SATA MagnHDDS that are said to be capable of 300 MB/Sec, the SATA specs are merely the theoretical maximum for the interface and do not reflect the actual transfer speeds which is around 20-80 MB/Sec on an average. Also an important point to keep in mind is that in an MHDD the rotating disk and the moving read write head implies different speed of data transfers for data stored in different parts of the platter. Data transfer is higher at the outsides of the platter than on the insides. In a SSD Drive that takes data from silicon chips, data transfer is instantaneous from every storage point and hence the transfer speed is fixed and is not an average calculation.



Now factor all this and see how this fits into a notebook computer. Most notebook computers these days have magnetic hard drives of capacity 80 GB. These are smaller and slower parts than what is commonly found on desktop computers and they are designed to withstand shocks better than their desktop counterparts. They also take a major share in the power consumed by the notebook. When portability is the key for adoption, the lowest power consumption is the goal. Any technology looking to replace MHDD should be able to match its capacities, transfer data at higher rates, use lower power and take the same or lesser physical space. Solid state technology is all set to replace these MHDDs in all these aspects very soon.

If you thought 64 GB was not enough space think again. I have been working on windows Vista for about 10 months now and a hard drive installed with Vista, Office 2007, commonly used applications and a couple of games occupies around 30 GB of space. That would leave a 64 GB hard drive with 34 GB free space that should easlity store 137 Audio CDs ripped at 128 kbps quality along with 20 High quality compressed movies. With the advent of portable music and video players you are more likely to push all this content into these devices or perhaps do live streaming from a media server (another new technology on the horizon). Even better you could buy an external hard drive of higher capacity if need be and use it only when you need to transfer data. You save power the rest of the time. You still have enough storage space for productive computing minus the entertainment in a worst case scenario.

If you feel the insufficiency of a 64 GB, behold. Manufacturers have announce Hybrid hard drives that have the usual magnettic platters for high capcity storage in addition to flash chips. This way the most commonly used applications and the operating system are stored on the flash memory and used from there while the magnetic platters are shut off to save power. When user data needs to be accessed in huge quantities from the magnetic platters, only then are the platters spun and data transferred. Recent trials of this technology report boot times for Windows XP at 10 seconds and resume from hibernate at 3 seconds.

With such benefits lurking around in the corner and Samsung all set to announce 128 GB NAND Flash chips by 2008 for lower cost than todays 64 GB, we should see this technology take off well in the next couple of years.