HARD DISK HAVE MADE PRECISION ENGINEERING COMMONPLACE

 Modern-day hard disk drives (HDDs) hold the interesting juxtaposition of being simultaneously the pinnacle of mass-produced, high-precision mechanical engineering, as well as the most scorned storage technology. Despite being called derogatory names such as ‘spinning rust’, most of these drives manage a lifetime of spinning ultra-smooth magnetic storage platters only nanometers removed from the recording and reading heads whose read arms are twitching around using actuators that manage to position the head precisely above the correct microscopic magnetic trace within milliseconds.

Despite decade after decade of more and more of these magnetic traces being crammed on a single square millimeter of these platters, and the simple read and write heads being replaced every few years by more and more complicated ones, hard drive reliability has gone up. The second quarter report from storage company Backblaze on their HDDs shows that the annual failure rate has gone significantly down compared to last year.

The question is whether this means that HDDs stand to become only more reliable over time, and how upcoming technologies like MAMR and HAMR may affect these metrics over the coming decades.

FROM MEGA TO TERA

The very first HDDs were marketed in the 1950s, with IBM's IBM 350 keeping an overall of 3.75 MEGABYTES on fifty 24 ″ (610 mm) discs, inside a closet determining 152x172x74 centimeters. Fast-forward to today, as well as a high-grade HDD in 3.5 ″ kind aspect (~ 14.7 × 10.2 × 2.6 centimeters) can accumulate to around 18 TB with standard (non-shingled) recording.

Whereas the IBM 350 rotated its plates at 1,200 RPM, HDDs for the past years have actually concentrated on minimizing the dimension of the plates, raising the pin rate (5,400-- 15,000 RPM). Various other renovations have actually concentrated on relocating the read and also compose heads closer to the plate surface area.

The IBM 1301 DSU (Disk Storage Space Device) from 1961 was a significant technology because it utilized a different arm with read and also compose go to each plate. It additionally introduced by utilizing wind resistant pressures to allow the arms fly over the plate surface area on a pillow of air, allowing a much smaller sized range in between heads as well as plate surface area.

After 46 years of growth IBM offered its HDD service to Hitachi in 2003. Already, storage space capability had actually boosted by 48,000 times in a much smaller sized quantity. Like 29,161 times smaller sized. Power use had actually gone down from over 2.3 kW to around 10 W (for desktop computer designs), while cost per megabyte had actually gone down from $68,000 USD to $0.002. At the same time the variety of plates avoided lots to just a pair at most.

The inner system and also its fifty 610 mm plates of the IBM 350 disk drive (DSU).

SAVING EVEN MORE IN LESS ROOM

Within 1 ″ Seagate MicroDrive.

At the exact same time, HDD storage space modern technology undertook a comparable adjustment.

After 46 years of advancement IBM marketed its HDD organization to Hitachi in 2003. At the very same time the number of plates reduced from lots to just a pair at a lot of.

As renovations from products scientific research allowed lighter, smoother (glass or aluminium) plates with boosted magnetic coverings, areal thickness maintained firing up.

Miniaturization has actually constantly been nitty-gritty, whether it had to do with mechanical constructs, electronic devices or computer technology. The hulking, vacuum tube or relay-powered computer system beasts of the 1940s as well as 1950s changed right into much less hulking transistor-powered computer system systems prior to developing into today's streamlined, ASIC-powered wonders. At the same time, HDD storage space innovation went through a comparable modification.

The control electronic devices for HDDs experienced every one of the advantages of boosted use VLSI wiring, together with progressively even more low-power and also exact servo innovation. As enhancements from products scientific research made it possible for lighter, smoother (glass or aluminium) plates with boosted magnetic finishes, areal thickness maintained skyrocketing. With the residential properties of all the private parts (ASIC product packaging, solder alloys, actuators, the rules of aerodynamics of HDD arms, and so on) far better comprehended, significant changes developed into step-by-step enhancements.

Six opened HDDs, from 8″ down to 1″. Photograph by Paul R. Potts [CC-BY-SA 3.0]

Although extreme miniaturization with HDDs has been attempted at least twice in the form of the HP Kittyhawk microdrive (1.3″) in 1992 and the 1″ Microdrive in 1999, eventually the market would settle on the 3.5″ and 2.5″ form factors. The Microdrive form factor was marketed as an alternative to NAND Flash-based CompactFlash cards, featuring higher capacity and essentially unlimited writes, making them useful for embedded systems.

As happened in other fields, the physical limits on write speeds and random access times would eventually mean that HDDs are most useful where large amounts of storage for little money and high durability are essential. This allowed the HDD market to optimize for desktop and server systems, as well as surveillance and backup (competing with tape).

UNDERSTANDING HDD FAILURES

Although the mechanical parts of an HDD are often considered the weakest spot, there are a number of possible causes, including:

Human error.

Hardware failure (mechanical, electronics).

Firmware corruption.

Environmental (heat, moisture).

Power.

HDDs are given an impact rating while powered down or when in operation (platters spinning and heads not parked). If these ratings are exceeded, damage to the actuators that move the arms, or a crash of the heads onto the platter surface can occur. If these tolerances are not exceeded, then normal wear is most likely to be the primary cause of failure, which is specified by the manufacturer’s MTBF (Mean Time Between Failures) number, reparatii laptopuri.

This MTBF number is derived by extrapolating from the observed wear after a certain time period, as is industry standard. With the MTBF for HDDs generally given as between 100,000 and 1 million hours, to test this entire period would require the drive to be active between 10 to 100 years. This number thus assumes the drive operating under the recommended operating conditions, as happens at a storage company like Backblaze.

Obviously, exposing a HDD to extreme shock (e.g. dropping it on a concrete floor) or extreme power events (power surge, ESD, etc.) will limit their lifespan. Less obvious are manufacturing flaws, which can occur with any product, and is the reason why there is an ‘acceptable failure rate’ for most products.