Thursday, February 08, 2007

Slides for Storage Device (Evening Session)

By: Trevor Craig, Jessica Hoy, Vinh Phan, and Yusuke Gemma

http://www.csusm.edu/fangfang/Teaching/HTMmaterial/New_Folder/Hardware_powerpoint.ppt
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4 comments:

Ulquiorra82 said...

Heh, No one mentioned Maxtor in both classes as a brand for internal/external HDDs. They are the best IMO.

6:51 PM
SurfPup said...

Hard Drives
I have kind of a love/hate relationship with hard drives. On the one hand, I really appreciate how the capacity and speed have evolved over the years. Anyone remember when programs were run from a floppy disk? I do, so I can certainly appreciate the ever increasing storage capacities and speed. I have more storage than I know what to do with, and my drive is old. It's a WD1200JB. 120 GB, 7200 RPM, 8MB cache. Fast for it's time. It still has an ATA-100 interface, but I don't worry about that. Even today's fastest drives don't transfer over 80 MB/sec, except maybe what comes from the cache. Funny how they have raced to upgrade the interface standard to ATA-133, SATA-150, and now SATA-300 speeds, when the drives just don't transfer data that quickly.

Even with all these changes, the hard drive is a slow link in the chain of everyday computing speed. Accessing the hard drive is 1000x slower than accessing RAM. I have 1 GB of RAM, and I still see Windows XP accessing the hard drive way more than I'd like. Unless your application runs entirely within free RAM, your hard drive is slowing down your computer experience. Not to mention the boot times to bring the PC up.

That's why I'm excited to see the advances in solid-state memory. Flash drives get bigger every year. These are exciting because the access time is so quick versus a hard drive. Still, the transfer rate is not currently that fast. Some of the early tests of Vista's ReadyBoost indicate that today's flash drives still have a ways to to. More on ReadyBoost here:
http://blogs.msdn.com/tomarcher/archive/2006/06/02/615199.aspx

More on ReadyBoost requirements here:
http://blogs.technet.com/jweston/archive/2007/01/31/windows-vista-readyboost-specs.aspx

"Flash storage devices must meet minimum performance requirements to support ReadyBoost, including 2.5 MB/s throughput for random 4K reads and 1.75 MB/s for random 512‑K writes.

Higher performance requirements must be met for the device to be designated as “enhanced for ReadyBoost”: 5 MB/s for random 4K reads and 3 MB/s for randmon 512‑K writes. Microsoft recommends that users use devices enhanced for ReadyBoost to take full advantage of the benefits provided by ReadyBoost."

Here is a reasonably fast and cheap hard drive, the Apacer 1GB Handy Steno USB Flash Drive, Model AH123:
http://www.directron.com/ah1231gb.html#pagetop

We should see hybrid hard drives this year combining flash memory with traditional hard drives. This should reduce power consumption for laptops, and has the potential for improving computing speeds. A Samsung prototype has a 1Gbit NAND flash buffer (128MB) buffer, versus the typical 8-16MB buffer found today.

12:20 PM
SurfPup said...

PRAM
This stands for Phase-Change RAM. It could be very exciting if it pans out. It's non-volatile like Flash RAM, but it's many, many time faster. It also requires less power. Great article here:
http://www.techworld.com/storage/news/index.cfm?newsid=7544

It's too exciting not to post.

"IBM has built a prototype storage device with two partners that they claim is 500 times faster than Flash.

It uses less than half the power of Flash memory and can be built in ultra-thin form factors most likely unavailable to Flash. In short, a Flash-killer and potentially the answer for a universal memory type for mobile devices.

Infineon spin-off Qimonda, and flash memory company Macronix will show the device at an IEEE conference in San Francisco this week. It uses a new germanium-antimony (GeSc) semi-conductor alloy in a device with a 3nm by 20nm cross-section - far smaller than today's flash and one predicted to be achieved in 2015 using Moore's Law extrapolations of chip component size.

Dr TC Chen, an IBM Research VP, said: "Many expect flash memory to encounter significant scaling limitations in the near future. Today we unveil a new phase-change memory material that has high performance even in an extremely small volume."

Most Flash memory used today has a "floating gate" charge-storing cell designed not to leak. Flash retains its stored data and requires power only to read, write or erase information. This makes thememory popular in battery-powered portable electronics. Non-volatile data retention would also be a big advantage in general computer applications, but writing data onto Flash memory is thousands of times slower than DRAM or SRAM.

Also, Flash memory cells degrade and become unreliable after being rewritten about 100,000 times. This is not a problem in many consumer uses, but is another show-stopper for using flash in applications that must be frequently rewritten, such as computer main memories or the buffer memories in networks or storage systems. A third concern for Flash's future is that it may become extremely difficult to keep its current cell design non-volatile as Moore's Law shrinks its minimum feature sizes below 45 nanometres.

The IBM/Macronix/Qimonda joint project's phase-change memory achievement is important because it demonstrates a non-volatile phase-change material that can switch more than 500 times faster than flash memory, with less than one-half the power consumption, and can do this when scaled down to at least the 22-nanometre node, two chip-processing generations beyond floating-gate flash's predicted brick wall.

Many other suppliers are working in this area. Samsung has already revealed details of its phase-change RAM (PRAM) switching 30 times faster than flash. Commercial availability is expected in 2008.

Intel and ST Microelectronics are collaborating in the area as well. Elpida aims to start commercial PRAM production by 2010.

Elpida, Samsung and Intel/ST speculate that PRAM is fast enough to replace DRAM in mobile devices. The IBM/Qimoda/Macronix device's switching speed makes it the fastest PRAM yet reported and backs up the idea of PRAM becoming a universal memory technology for mobile devices. "

12:25 PM
SurfPup said...

By the way, there is a website dedicated just to storage devices. They test hard drives and publish the bencharks, and more.

http://www.storagereview.com/

12:28 PM

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