Holographic Data Storage

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Serial ATA

Serial ATA is an evolutionary replacement for the Parallel ATA physical storage interface. Serial ATA is scalable and will allow future enhancements to the computing platform. Serial ATA is a drop-in solution in that it is compatible with today's software, which will run on the new architecture without modifacation. industry benefits of Serial ATA include systems which are easier to design with cables that are simple to route and install, smaller cable connectors with improved silicon design, lower voltage which alleviates current design requirements in Parallel ATA and compatibility with today's software which will run on the new architecture without modification. End users will benefit by being able to easily upgrade their storage devices. Configuration of Serial ATA devices will be much simpler, with many of today's requirements on jumper and settings no longer needed. Serial ATA is an evolutionary replacement for the Parallel ATA physical storage interface and will allow future enhancements to the computing platform. Specifically, the thinner Serial ATA cable addresses OEM's concerns regarding airflow around the Parallel ATA cable, and enables design of smaller PC chassis, as well as silicon vendors concerns regarding 5 volt tolerance support in future designs. Serial ATA electronics and connectors will differ from Parallel ATA, however the technology is software compatible with Parallel ATA and requires no changes to any operating systems. It is anticipated that there will be adapters to facilitate forward- and backward-compatibility of hard disks on PC systems. Serial ATA supports all ATA and ATAPI devices, including CDs, DVDs, tapes devices, high capacity removeable devices, zip drives, and CDRW's. Features in a nutshell: 150 MB/s maximal transfer rate now - 300 MB/s (Serial ATA II) and 600 MB/s (Serial ATA III) in near future Hot-Plug capability Two energy saving modes: partial and slumber Overlapping (commands) Tagged command queueing Data cable containing 7 wires, connector's width only 8 mm Lenght of cable up to 1 meter

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Fluid Dynamic Bearing / Ball Bearing

Traditionally, Toshiba HDD have ball bearing spindle motors. These ball bearings are metal balls that are lubricated by a thin layer of grease. Imperfections in the roundness of the bearings and within the raceways (in which the bearings reside) set up random vibrations that can cause problems (increased "Non-Repeatable Run Out" - NRRO) for the servo system. Additionally, the ball bearings start to wear with continuous use, even more so when subject to excessive shock. A symptom of this wear is the spindle motor becoming noisier and read/write performance decreasing. A solution to these issues is to use spindle motors that use a fluid dynamic bearing (FDB). FDB motors have lubricant oil rather than metal ball bearings to separate the rotor and stator. Advantages of using a FDB motor: Greatly reduce NRRO to improve servo performance. This will allow for higher areal density. Improved reliability by not having any metal ball bearing. Quieter due to not having metal ball bearings. Increase in non-operating shock performance.

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Hybrid Hard Disk Drives

A Hybrid Hard Disk Drive combines a conventional HDD and non-volatile flash memory.

Unlike most standard hard drives, the hybrid drive in its normal state has its platters at rest, as if it were off. Instead of writing data directly to the platter, files are saved to a flash buffer. The hybrid drive platters will spin up in only two situations:

• When the buffer begins to near its capacity. The platters of the hard drive will spin up, and all of the data in the buffer will be cleared onto the hard drive. The platters return to an off state, and the flash cache is empty and ready for use.
• When the user needs data from the hard drive that is not stored in the buffer. In this case, the platters spin up to load the file into the buffer, and afterwards return to an off state again.

Since a hybrid drive uses flash memory, the buffer is able to retain all the data even in the event of a sudden power failure or reboot, and can even store boot-up data into the buffer.

Benefits of a Hybrid HDD:

• Lower power consumption. Because the platters will mainly be in an off state (when not required for any data transfer), power consumption by the hard drive can be reduced. For notebooks this feature can greatly increase the system run-time while on battery.
• Reduced boot time/wake up time. The computer can immediately start to read data from the flash memory after powering on whilst the HDD needs time to spin up and initialize. The same appears after start-up from sleep mode.
• Lower heat generation. The reduced spinning of the platters also greatly lowers the amount of heat generated from the moving parts of the hard disk drive.
• Lower noise level. As the platters of the hard disk drive are only spinning when necessary, and less cooling required, hybrid drives on average have a lower noise level.
• Improved reliability. As the platters are spinning less, the wear and tear on the hard drive is reduced. Therefore Hybrid drives should be able to last longer than today's standard notebook drives. Additionally, the risk of physical damage through head disk interference ("HDI") is reduced, as the heads are more often in the rest position.

The flash memory on Hybrid hard disk drives should not be seen as a replacement for the conventional DRAM-based cache on hard disk drives. The usage of this "buffer" will highly likely be maintained in the future.

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Free Fall Sensor (FFS)

Notebooks have been developed to increase mobility. A small form factor hard disk drive such as 2.5" and 1.8" HDD is one of it’s main components and it is therefore exposed to the same risks as the notebook itself: Shock, vibration and – even more serious – the impact after a drop.

One of the most harmful things that could happen to your hard disk drive is a so called "head disk interference" (HDI), which means nothing else than a collision of the most sensitive parts of a HDD, the read/write heads and the surface of the storage media. Through the impact, not only the heads can be damaged, but vital data stored on the hard disk can also be damaged or lost. HDI are mostly caused by shock impacts, e.g. when a laptop is dropped.

Toshiba Storage Device Division has developed an effective technology to prevent damages caused by an impact after a free fall. The principle is as simple as it is effective: When a possible drop acceleration is measured, the read/write heads are retracted from their location above the media and locked in a secure position. In other words: The shock robustness of the drive is significantly increased.

Obviously, the technology is more complicated. A three axis sensor, a so called "Low-Power Linear Accelerometer", measures the acceleration magnitude, which in normal conditions is approx. 1 G. When the hard disk drive is falling, the acceleration magnitude changes to approx. 0 G. The sensor detects this transition phase from 1G to 0G and retracts the read/write heads from the media preventing HDI.

The accelerometer is so fast, that a fall from as little as 10 cm (4 inches) is detected and the read/write heads are secured. In other words, the whole process of measuring the change in G force, retracting and securing the heads lasts less than 150 milliseconds.

Toshiba hard disk drives with Free Fall Sensor technology are the first choice for truly mobile storage devices.

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Perpendicular Magnetic Recording (PMR)

Conventional hard disk drives using "Longitudinal Magnetic Recording" (LMR) store data on a magnetic disk as microscopic magnet bits aligned in plane. Although advances in magnetic coatings continue to improve data recording densities on HDD, the magnetic bits repulse each other due to in-plane alignment.

Squeezing more bits on to a disk will eventually reach a point where crowding degrades recorded bit quality because the bits start to influence each other (magnetic coupling). In worst case they begin to flip over: The affected bits loose orientation and the information is lost. This is called the "Superparamagnetic Effect". This problem placed fast-approaching limits on storage capacities.

The solution to this problem is called "Perpendicular Magnetic Recording" (PMR) where the magnetic bits are not aligned in plane but orientated vertically. By standing the magnetic bits on end, perpendicular recording reinforces magnetic coupling between neighbouring bits, achieving stable higher recording densities and improved storage capacity. By using PMR the capacity of hard disk drives can be increased by up to 10 times. Furthermore due to the increased data density the data transfer rate is also increasing compared with HDD’s using the LMR technique.

One of the technical challenges when developing PMR was the fact that the physical characteristics of the PMR media require a much narrower gap between read/write head and media in order to be able to read and write data.

Professor Shun'ichi Iwasaki from Tohoku Institute of Technology in Japan initially determined in 1976 that it was possible to increase areal density of data media by organising magnetic bits vertically to the rotational direction of the media rather than horizontally.

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Full Disk Encryption (FDE)

In case a computer is stolen, any information stored on a regular hard disk drive can be compromised and sometimes, the external access to confidential information is more sensitive than the loss of the computer hardware.

With the Toshiba "FDE" technology, the unauthorized access to the hard disk drive is made very difficult.

"FDE" is one of the "most transparent" encryption products available and fully encrypts the entire hard disk drive. Once installed the user just has to authenticate once before booting up the system, and if successful the hard disk drive is unlocked and behaves like any conventional HDD. The user doesn't need to decide what files to encrypt and what not to encrypt because with FDE everything is encrypted.

Any data generated on the computer and stored on the hard disk drive is scrambled by a System-on-Chip (SoC), which encrypts the information before it is stored on the platters by using a password-generated key. By using this procedure, the content is already coded on hardware level (independent from partitions or file systems) with a higher level of security than regular software coding systems.

Only when the correct password is provided and the protected ATA permits access, the System-on-Chip will descramble the data with the key as it is retrieved.

The benefits of FDE:

• Addresses highest level data security in the event of notebook theft
• Improvement over hard disk drive software-based password security
• No decrease of hard disk drive performance
• Everything including the swap space, temporary files etc. is encrypted.
  Encrypting these files is important, as they can reveal important confidential data.
• With full disk encryption, the decision of which files to encrypt is not left up to users
• Support for pre-boot authentication

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Heat Assisted Magnetic Recording (HAMR)

HAMR is an acronym for Heat-Assisted Magnetic Recording.

It describes a future HDD recording technology that allows even higher areal densities on Hard Disk Drive media than achieved with Perpendicular Magnetic Recording (PMR).

With HAMR data is magnetically recorded on special high-stability storage media after the precise spot where data bits are being recorded has been heated up using laser thermal assistance. When heated, the medium becomes easier to write, and the rapid subsequent cooling stabilizes the written data.
These media materials can store single bits in a much smaller area without being limited by the "Superparamagnetic Effect". This is the same effect that limits the areal densities of platters used in conventional hard disk drives recorded with LMR (Longitudinal Magnetic Recording).
The only catch being that they must be heated to apply the changes in magnetic orientation.

HAMR will not appear in general HDD products before 2010 and 50 Terabits per square inch areal densities may be possible in the 2020 or later area. The transition from PMR to HAMR may well have started in 2010.

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Discrete track recording (DTR)

Toshiba has presented the Discrete Track Recording Technology (DTR) in September 2007.
DTR is a new breakthrough recording technology that will increase the capacity of storage media used in PMR hard disk drives by up to 50 per cent. Therefore it will especially take the small form factor HDD’s, such as 1.8 inch and 2.5 inch drives, to a new level of enhanced capacity.
Small form factor HDDs are now found in such applications as mobile PCs, all kinds of portable multimedia players, digital video cameras, and also car navigation systems. This market has a strong demand for larger data capacities.

The DTR technique, as its name suggests, separates out parallel data tracks on HDD media by inserting gaps, also named “grooves”. This separation reduces signal interference between adjacent data tracks resulting in improved signal quality and allowing the pitch of the tracks to be shortened. The tracks can be made narrower, and more of them can be hosted onto the disk. This will enable recording densities of up to 516 megabits per mm2 (333 gigabits per square inch).

The technique is also applied to the servo pattern, some extra information added to the disk being an essential part of the read/write head positioning system.

DTR technology is based on research of Japan's New Energy and Industrial Technology Development Organization (NEDO).

Toshiba expects to lead the industry in mass production of HDD integrating DTR technology. The current plan is to put DTR drives into mass-production during 2009.

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