The tenth line in the perpendicular world

Evgenie Rudometov,

Victor Rudometov

authors@rudometov.com

Responding to requirements of the market in vysokoemkih disk drives, company Seagate Technology has developed and has released the tenth generation of the 3,5-inch hard disk drives, by tradition received name Barracuda. The model in size of 750 Gbytes with interface Serial ATA became the high representative of this bar 

All its accessories participate in modern computers in information processing practically, however for long-time and non-volatile storage of great volumes of the information the hard disk drive (HDD) responds. Despite appearance of the alternative arrangements fulfilling given function, HDD remains the main saver of programs and data, whose sizes permanently increase.

From year to year their technical parametres improve. And first of all it concerns growth of the information capacity providing saving of the increasing sizes. So, for example, more recently it was possible to release 500 Gbytes of the arrangement. Information capacity growth is provided mainly at the expense of increase in density of an information storage at magnetic disks. This metric increased for a long time twice everyone year-one and a half.

However, despite successes of the engineers working over improvement of traditional processing technique of writing, the limit is obviously viewed. Its presence is linked to increase in density of the written information which growth the last years was sharply decelerated.

The matter is that writing in HDD is carried out by means of the magnetic field, formed by a special head, on the disks coated with a magnetic medium. The writing field is oriented horizontally and varies according to a stream of the arriving information. This field magnetises units — the domains of a magnetic layer representing elementary magnets. They the fields allocated according to a direction of horizontally plane of a disk. Stability of magnetised areas depends on force of the field and features of used substances. Unfortunately, the increase in the bit density providing growth of size of disk drives, is accompanied by reduction of magnetic domains. It reduces stability of magnetised sites. The matter is that reduction of domains leads to reduction of their energy. As a result the probability of spontaneous change of a state of the domains called by external and internal effects, for example, at the expense of change of temperature, environing fields, space particles, etc. increases . The given limit has been named by the paramagnetic. Its approaches it was expected for a long time — since times of disk drives, whose size was calculated in hundreds megabytes.

But thanks to perfection of processing technique and substances it was permanently removed. Nevertheless, this process could not proceed infinitely. And designers had to reconsider the way of writing providing change of orientation of the field and domains in the radical.

Not pressing in technical details, it is necessary to mark, that the main changes are linked to the field usage which vector is oriented now not in a parallel way disk planes, and is perpendicular. According to these orientation of magnetic domains which also are allocated now perpendicularly has varied also. It has allowed to raise their density without necessity of their critical reduction. Energy of domains has as a result raised and the probability of any change of their state has essentially decreased.

All it has allowed to raise dependability of an information storage at increase in density and the common information capacity of disk drives.

The first 3,5-inch hard disk drive with perpendicular processing technique of writing (and reading) became HDD to company Seagate Technology (Seagate).

Within the limits of next, already the tenth bar 3.5-inch HDD, received official name Barracuda 7200.10, the upper model is the disk drive with information capacity of 750 Gbytes (1 Gbytes =   1 000 000 000 byte).

Appearance of the given model is presented in a Fig. 1.

Fig. 1. Hard disk drive Seagate Barracuda of 7200.10 750 Gbytes

Except information capacity, the important features of the given model are the built in cache memory in size of 16 Mb, and also serial interface Serial ATA with a transfer rate to 300 Mb per second — SATA/300 (a Fig. 3).

Besides, given model supports processing technique NCQ, providing the raised speed of processing of sequence of simultaneously arriving inquiries to HDD on reading and a data recording. This processing technique provides storage of inquiries and optimises queue, minimising number of movings of heads on disks that reduces unproductive time and increases the common speed of data access.

In a Fig. 2 marking of model Seagate Barracuda of 7200.10 750 Gbytes with interface SATA/300 is presented .

Fig. 2. Marking of 750 Gbytes of model Seagate Barracuda 7200.10 with interface SATA/300

Considering the specified high model, it is necessary to mark, that besides it in the bar of disk drives Barracuda 7200.10 there is also a variant with the same size of 750 Gbytes, but with interface Parallel ATA/100. The low representative of the given bar now is the arrangement with size of 200 Gbytes. All bar consists of following models: 750, 500, 400, 320, 250, 200 Gbytes.

Table 1. Key parametres of models HDD Barracuda 7200.10

Size of models, Gbytes	From 200 to 750
Interfaces	Serial ATA/300 with NCQ or Ultra ATA/100
Size of the cache memory, Mb	16, 8
Speed of rotation of disks, rpm	7200
Admissible shock loads, g	By operation – to 68, At storage – to 300
Band of an operating temperature, With	0-60
Acoustic noise level, Bell	2,7, 3,0 (by retrieval)
Guaranty period, years	5

Model 750 of Gbytes incorporates four hard disks. Other disk drives contain from two to three disks.

As to concrete values of productivity of 750 Gbytes of model in widespread applied tasks they can be received only in the course of testing.

As measurement standards to which the given high model was compared, earlier released high-powered disk drive of 500 Gbytes — the upper model of bar Barracuda 7200.9 used  .

Pattern of the system used in testing of hard disk drive Seagate Barracuda in 7200.10 size of 750 Gbytes:

·         the Motherboard of Intel D925XCV (a chip set i925X, memory DDR2, the slot of video PCI Express x16, ports PATA and SATA),

·         the Processor of Intel of Pentium 4 with clock rate of a kernel of 3,4 GHz (LGA 775, kernel Prescott, the bus of 800 MHz, processing technique Hyper-Threading),

·         the Disk drive on hard disks 1: HDD Seagate ST3750640AS (Barracuda 7200.10, 750 Gbytes, 16 Mb of the cache memory, 7200 rpm, SATA/300),

·         the Disk drive on hard disks 2: HDD Seagate ST3500641AS (Barracuda 7200.9, 500 Gbytes, 16 Mb of the cache memory, 7200 rpm, SATA/300),

·         Dynamic storage 2 x 1 Gbyte, Apacer DDR2 667,

·         ASUS EXTREME AX 600XT Videoadapter (chip ATI Radeon X600XT, bus PCI Express x16),

·         the Optical CD-ROM drive: ASUS CD-S400/A (40x),

·         the Operating system: Windows XP.

As the testing tool known package Winbench 99 used .

In Table 2 – Table 3 and in a Fig. 3 – Fig. 4 are resulted results of comparative testing.

Table 2. Results of performance of test Winbench 99 Disk Transfer Rate

Models HDD	Winbench 99 Disk Transfer Rate
	Beginning	End
750Gb SATA	78900	44400
500Gb SATA	59900	33200

Fig. 3. Results of performance of test Winbench 99 Disk Transfer Rate

Table 3. Results Winbench 99 High-End Disk WinMark 99

Models HDD	Winbench 99 High-End Disk WinMark 99
750Gb SATA	48800
500Gb SATA	42700

Fig. 4. Results of performance of test Winbench 99 High-End Disk WinMark 99

From the resulted results of testing follows, that disk drive Seagate Barracuda of 7200.10 750 Gbytes with interface SATA/300 possesses not only a high capacity, but rather high efficiency.

Hard disk drive Barracuda in 7200.10 size of 750 Gbytes has been given by company EAST SIDE Consulting