Hardware Reference
In-Depth Information
Hard Drive Advancements
The first hard drive appeared in 1956. One year later in 1957, Cyril Northcote Parkinson
publishedhisfamouscompilationofessaystitled
Parkinson's Law
,whichbeginswiththe
statement, “Work expands so as to fill the time available for its completion.” A corollary
of Parkinson's most famous “law” can be applied to hard drives: “Data expands so as to
fill the space available for its storage.” This, of course, means that no matter how big a
drive you get, you
will
find a way to fill it. I know that I have lived by that dictum since
purchasing my first HDD nearly 30 years ago.
Even though I am well aware of the exponential growth of everything associated with
computers, I am still amazed at how large and fast modern drives have become. The first
hard drive I purchased in 1983 was a 10MB (that's megabyte, not gigabyte) Miniscribe
model 2012, which was a 5 1/4-inch (platter) drive that was 203.2mm×146mm×82.6mm
or 8 inches×5.75 inches×3.25 inches in overall size and weighed 2.5kg (5.5 lb., which is
heavierthanmanylaptopcomputers)!Bycomparison,amodern1.5TB31/2-inchdriveis
about53/4inches×4inches×1inch(146mm×102mm×25mm)inoverallsize,weighsonly
1.54lb.(0.70kg),offering150,000timesmorestorageinapackagethatisaboutone-sixth
the size and one-fourth the weight of my old Miniscribe.
Obviously, the large storage capacities found on modern drives are useless unless you can
also quickly transfer the data to and from the disk. The hard disk as found in the origin-
al IBM XT in 1983 had a constant data transfer rate from the media of about 100KBps.
Today, most commonly used drives feature average transfer rates of 100MBps or more,
an increase of more than 1,000 times. Much like the increase in drive capacity, the speed
of the interface has come a long way since the MFM and RLL interfaces that were com-
moninthe1980s.Asalways,theinterfacesaremuchfasterthantheactualdrives.Modern
interfaces offer data transfer rates of up to 133MBps for Parallel AT Attachment (ATA),
150MBps, 300MBps and 600MBps for Serial ATA (SATA), 320MBps bandwidth for Ul-
tra-320 SCSI, and 300MBps or 600MBps for Serial Attached SCSI (SAS). All these in-
terfaces are much faster than the drives they support, meaning that the true transfer rate
you will see is almost entirely limited by the drive and not the interface you choose. The
modern interfaces have bandwidth to spare for future developments and advances in hard
disk technology.
Note
The topic
Parkinson's Law
(ISBN: 1-56849-015-1) is still in print and is in fact considered
one of the essential tomes of business and management study even today.
