Archive for the 'IBM' Tag

Solid state society: The future of common data storage

Friday, June 29th, 2007

Fifty-one years ago, IBM did something amazing, something that changed the world and kick-started the computing revolution twenty years before Intel and Apple and Microsoft and everyone else declared they were open for business: IBM invented the hard drive.

A monster of a machine, a behemoth, one ton of spinning metal the size of a fridge held exactly five megabytes via 50 two foot platters and a bunch of controller hardware and buffer memory. This hard drive was the first of it’s kind, and helped spawn an entire industry of data storage; not only was it faster and easier to use and maintain compared to tape media, it was also expensive and only a few companies could afford this.

The technology over the next few years shrank and increased in performance, and stories of “wash machines” dancing across the data center were well known. More and more companies started buying them to replace or supplement their tape drives, and eventually tape died out in the commercial sector.

Eventually, the three or four home computing revolutions come and go, and the two portable device revolutions come and go. Wash machines become small external units, those external drives become internal (5.25″ full height), and then they become smaller (3.5″) and smaller (2.5″) and smaller (1.8″) yet. Megabytes become gigabytes become tens and hundreds of gigabytes and finally, as of a few months ago, terabytes.

All of this technology ultimately works the same way: spinning platters with magnetic heads reading what an IBM engineer once named “magnetic milkshake.” The one single major flaw in this design is that anything that moves will eventually break down. Spinning drives slower won’t decrease the wear and tear, and neither will cooling them; and new bearing designs? They decrease noise and some wear and tear, but do not prevent mechanical failure.

We’ve invented new technologies, such as redundant arrays of inexpensive disks (RAID) to both increase performance and decrease the chances of mechanical failure eating your data. A suitably sized RAID 6 array can have two drive failures before you risk data loss. An array of, say, six to ten drives for such an array is also huge and outside the realm of most people; and I haven’t seen Apple issue iPods with RAID arrays yet.

In addition to all of this, the magnetic heads have to move across the platter to read and write specific areas, which increase the time it takes to read random data (sequentially read data suffers from this less). If mechanical failure was the major issue of this design, seek times is the secondary issue.

Flash, a member of the Justice Lea–oh, wait…

Now, in 1984, a Dr. Fujio Masuoka invented flash memory: a non-volatile memory that can be used as data storage in the same way you’d use tape or hard drives, and flash has no moving parts nor does it use large amounts of power like hard drives do because of spinning platters. You see flash everywhere now, in your cell phones, in your digital cameras, in your hand held game systems, and also in your Wiis. We call drives built out of this technology: solid state drives.

Laptops are now the key target: laptops never have enough power, and battery technology is not keeping pace with our advancements with other technology, and until Santa Rosa more than 3 hour battery life under normal conditions on most laptops was impossible… now it’s simply medium difficulty. Flash technology now has gotten very interesting due to the fact everyone from laptop manufacturers to silent computing aficionados to even the enterprise sector wants flash tech to replace their spinning milkshakes.

I want to mention STEC and their ZeusIOPS series of flash drives. Built around high end flash that is both incredibly fast and reliable, and can write a sector before it fails some astronomically high number of times (from what I see, a magnitude of order more than most hard drives). These drives are fast enough to realistically saturate a SATA/300 connection, although they only come in Fibre Channel. For those wondering, the 256 gigabyte model of this drive is around $10k.

The reason I mention them is because this, as of this writing, is the elite of solid state drives*, however, 99.9% of the people out there simply cannot afford such a drive, nor do they make SATA versions or 2.5″ versions. There is their Zeus series which does have SATA and 2.5″, but like ZeusIOPS, its very expensive.

Three other companies to look out for are A-Data, Mtron, and Samsung. You’ve probably already heard of A-Data and Samsung, they’re both well known suppliers of consumer flash cards and USB flash keys. Samsung soon is coming out with 16 and 32 gigabyte CompactFlash card and already have their own series of solid state drives in 2.5″ form factor. The largest available 2.5″ drive of theirs is the 32 gigabyte model, which is big enough to install OSX or Vista on and most of your usual apps. Samsung has stated they are working on 128 gigabyte versions of their 1.8″ and 2.5″ series as well..

A-Data is the world’s second largest manufacturer of flash products, and to keep from falling behind they announced they are now manufacturing their own SSD family of drives, including a 128 gigabyte 2.5″ model.

Mtron is a newcomer to the SSD market, however they are working on technology to reduce the cost of SSD drives, and also have 2.5″ 64 gigabyte drives that can write up to 80 megabytes/sec sustained, which makes them useful for high bitrate video recording and playback; comparatively, even most new laptop hard drives cannot write that fast. They are soon coming out with 128 gigabyte models as well.

I think these three companies are going to, within the next 5 years, power the solid state drive revolution and bring us drives meeting or exceeding current hard drive sizes and match price as well. I think within ten years, traditional hard drives will no longer be sold, the same way LCD replaced CRT.

As a side note, companies like Sandisk, PNY, and Transcend also have SSDs either in the works or ones already available, however from what I’ve seen they’re all 8 or 16 gigabyte models with 32 and 64 gigabyte ones around the corner. They’re behind Samsung and A-Data, and don’t seem to be making any move to catch up.

Three drives, seven years

Tuesday, October 24th, 2006

Over the past six years I’ve owned only three drives. My oldest of the three, a IBM Deskstar 75GXP, continues to spin although it is now the oldest component in my system; it’s two younger brothers are Seagate 7200.8 and 7200.10.

So, in the past seven years, we really haven’t had much in the way of performance increases. Moore’s Law doesn’t apply here, as performance doesn’t double every two years, and Kryder’s Law (the storage analog to Moore’s) states that storage space per square inch doubles every two years, but has no mention for performance.

IBM Deskstar 75GXP 30GB IBM-DTLA-307030:

  • 7200 RPM
  • Ultra ATA/100
  • 2MB buffer
  • 15ms average seek time
  • Released 04/2000, approximate cost of $250
  • Once called the fastest consumer drive ever

Seagate Barracuda 7200.8 250GB SATA NCQ ST3250823AS:

  • 7200 RPM
  • SATA 1.5Gb/sec with NCQ
  • 8MB buffer
  • 11ms average seek time
  • Released 04/2004 approximate cost of $250
  • Also once called the fastest consumer drive ever

Seagate Barracuda 7200.10 400GB SATA NCQ ST3400620AS:

  • 7200 RPM
  • SATA 3.0Gb/sec with NCQ
  • 16MB buffer
  • 8.5ms average seek time
  • Released 02/2006, approximate cost of over $300
  • Once called the fastest consumer drive ever, and is still one of the fastest

As you’ve noticed, rotational speed (and thus rotational latency) has stayed constant, and bus bandwidth has only increased three fold (100MB/sec six years ago to 150MB/sec two years ago to 300MB/sec now), average seek latency is almost halved, and cache buffers have increased eight fold.

None of that actually states what the performance is, of course. According to hdparm -t (and using the best out of five, with nothing on the system running not even X), the Deskstar is the slowest at 35.82 MB/sec, the 7200.8 coming in at 63.09 MB/sec, and the 7200.10 coming in at 72.00 MB/sec.

May be now it is time for a new law governing computing (and named after myself by myself in bad taste):

McFarland’s Law: The performance of consumer hard drives doubles roughly every six years.