A BRIEF HISTORY OF DATA STORAGE & A BRIEF EXPLANATION OF THE BINARY SYSTEM (Part 2 of 2)
by Ron Hirsch - Boca Raton Computer Society

In part 1 of this article, I introduced you to the binary system. In part 2, I’m going to give you a brief history of the primary way that data is stored in your computer. Remember, we are not going to use light bulbs, but we are going to use something which has two states. The light bulbs in part 1 had an on or off state. The use of magnetic material will now be substituted. And, even though it is not necessarily done as I will note, it may be simpler to think of a magnetic situation where something is magnetized to be a south pole, or a north pole. Since this represents 2 states, it qualifies as a binary device to store and access values.

MAGNETIC STORAGE ARRIVES
Some of the earliest magnetic devices were floppy disks, which were really floppy, unlike the  the floppy disks you may remember, which were 3.5", and were encased in a hard thin plastic case . The early 8" floppies used a thin sheet of plastic, which had a layer of very fine iron based coating placed onto it. Floppy disks are actually similar to the old audio record disks we used to play in the past. If you remember, these records had a fine spiral groove on them, and a special needle in a cartridge at the end of a tone arm, that rode in that spiral track, and produced sound based on small “bumps” and holes at the bottom of the groove. When vinyl LP records came along, they managed to get more music in the same space, by making the groves smaller, and the needle finer.

Well, the floppy discs stored bits of data in a similar fashion, except the groove was an electronic groove, and the “bumps and holes” were magnetized “spots”. And the arm was a very lightweight floating arm with a magnetic reading or writing device on the end, which would read or write the all the magnetic spots, which are bits of information, which can then be converted into numbers or characters, as applicable.

Needless to say, the arm reading or writing all this magnetic info cannot really be allowed touch the surface, but must float just above it. If it touched the surface, it could scrape off material, and cease to function properly. And each magnetic bit must be sufficiently isolated from its neighbors, so that the magnetic sensor in the floating head can reliably read each bit at a rapid pace. Sounds like a tough task, considering that the number of magnetic “spots” on the old floppies did reach into the millions. As time marched on, smaller floppies arrived, bringing the size down to 3.5 with improved mechanical and electrical specifications.

THE HARD DRIVE STARTS TO COME OF AGE.
When my company got its first computer, an IBM 32, the IBM rep told us that the built in storage capacity of 4 MB would be enough to last us for many years. We believed that story for about 1 week after we got the IBM 32. In addition, not only was the storage capacity very little, but the built in & non interchangeable monitor was so small, that it bordered on being useless. So we called IBM, and they agreed to take the unit back, and sell us an IBM 34, which did have more storage, and a better display. And not too much later, we again moved upward and went for the model 36. In that era of the late 70's and early 80's, cooling the computer, which was a huge monster, required that it be housed in its own small specially air conditioned room, which we constructed.

Now, needing more memory storage space, we purchased IBM’s latest hard drive package, which was the size of a large refrigerator, and came with a single 64 MB platter. And, it could accept a number of additional 64 MB platters. These platters were the size of large pizza. I don’t’ recall the cost of each platter, but the total unit, including the platters was many thousands of dollars.

Later on, in the mid-late 1980's the cost for a 30 MB hard drive for use in a personal computer had come down to about $300. When my first personal computer, the IBM PC AT, had the 30 MB hard drive fail one week after the one year guarantee expired, it cost me about $300 (plus labor) to have a new unit installed in my machine. I stayed with the same 30 MB size, as the store representative said I’d never need any more than that. In retrospect, that size drive would only hold about 5-10 images from a digital camera in current times.

HARD DRIVES CONTINUE TO GROW IN CAPACITY
When I had my 30 MB hard drive, it was actually 240 million bits. I could not imagine that many magnetic spots being available on that rapidly spinning disk inside the case. To me, that was unbelievable then. And to have all the storage capability, and to read and write from the drive at millions of bits per second, how could this be possible?

I moved on with a new computer every 4 years or so And every machine had a bigger hard drive, and it needed it. The Windows operating system needed more and more drive space. And the programs also needed more space. And the hard drives started adding more platters inside the case. Each platter had its own read and write head, and the rotational speed continued speeding up to make things perform faster. And, the price per megabyte of  space continued to drop. It seemed as if there was no limit. And how could these complex mechanical monsters continue to get better and cheaper?

CHECK OUT THIS COMPARISON
My original IBM 30 MB drive cost about $10 per MB, which is $10,000 per GB. Today’s hard drives are selling for about $90 for a 1 terabyte drive, which is 9 cents per GB. In other words, storage space in the early days was 100,000 times more expensive than today. And, the size has shrunk dramatically. Current 1 TB drives are smaller than my old 30 MB IBM drive. 

Here are some numbers which are hard to believe, but are true. The magnetic “spot” which is one bit on a hard drive has continued to shrink in size. That spot has gotten down to one millionth of an inch in diameter! And the rate at which bits are read from and written to has reached into the hundreds of million per second! This is inconceivable. Fortunately, the hard drive doesn’t know that, and it continues to purr along anyway.

And, the power drain is much less for today’s 1TB drive than the old 30 MB IBM drive. And, the statistical failure rate is claimed to have the drive run continuously for many years with no missed bits. I challenge this statement. In the course of my computer activities, I’ve had at least a dozen hard drives fail. And in recent times the failure rate has been high. In the past year, I’ve had 4 hard drives fail in 3 different machines. At the work they are doing, and the specs they are seeking, I’m not surprised. Fortunately, in every failure case, the drive was the C system drive, where I use True Image weekly. And, I always keep new spare drives around. So, a quick change out, and an image restore, and that machine is back in business. 

JUST HOW BIG IS A TERABYTE (TB)?
A terabyte is 1 followed by 12 zeroes, or 1 trillion bytes. If you started counting at a rate of 1 count per second, to reach 1 trillion, you would have to continue counting for about 30,000 years. 

WHAT DOES THE FUTURE HOLD?
In the past, it was always felt that since the magnetic hard drive is a “mechanical” device, it would ultimately be replaced by a nonmechanical component. Holographic storage seemed to be a potential medium. It had no moving parts, had virtually unlimited capacity, and looked promising. But, it has yet to meet its expectations. The newest kid on the block is SSD. This stands for Solid State Drive. You probably already use such devices, as this approach is used in digital camera memory cards, and flash drives. They have now been designed to have larger capacities and packaging/interface to be interchangeable with current magnetic hard drives.

The pricing is still much higher than magnetic drives, about 10 times as high,  but this should drop rapidly in the next few years. Their performance can actually run circles around their magnetic counterparts. And, with no moving parts, they should last almost forever. Some manufacurers have already started building them into their high end models.

If you find this material useful, you may want to download this article in PDF format, from our web site http://www.brcs.org/hirsch.php. This allows readers to keep the material either as a PDF file, and/or print it out, and place it in a looseleaf notebook for future reference. Remember, the PDF version offers full color, wherever color elements might be involved, and often images which could not be used in the Boca Bits hard copy. So, if there are color elements in the original, the PDF copy will display them that way.