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Server disk drives SFF from Seagate

Evgenie Rudometov,

Company Seagate has presented recently Savvio — the first-ever bar of 2,5-inch hard disk drives with speed of rotation of a spindle of 10 000 turns in a minute, the highly reliable to market highly reliable, efficient, compact systems of data storage, Blade and 1Uсерверов, workstations.

Development of the architecture of computers is closely linked to perfection of their accessories. On these accessories depend both productivity, and functional properties. Perfection process has mentioned all components of permanently becoming complicated computing systems in which find incarnation the newest innovations of IT branches.

Solid-state technologies operate with the lesser scales, and according to miniaturization of units the density and number of transistors promptly grow in chips. By way of illustration it is enough to result, for example, central processor units. The number of transistors in these superdifficult chips doubles each one and a half-two year. This a rule with enviable accuracy is fulfilled already more than three tens years and it is known as Moore's law. By the way, this empirical law is quite often resulted by way of illustration possibilities of the solid-state technologies defining prompt evolution of processors. It is necessary to add, that silicon chips of the processors oriented to the mass consumer market, already contain more  than 100 000 000 transistors, and efficient models of server processors, for example, Intel Itanium  2 — already more than semibillion.

However, recognising high rates of development of the architecture of processors and increase in number of their units, it is necessary to remind, that there are computer accessories, whose perfection and growth of possibilities occurs even faster. Such accessories are disk drives on hard disks (hard disks) which size doubles, at least the last ten years everyone of 9-12 months. And it means, that speed of evolution of these arrangements twice exceeds the rates reached in solid-state technologies. The construction of disk drives, and their interfaces are thus perfected also. Speed of data access as consequence grows at constant reduction of the price of storage of unit of the information. In addition to it improvement of technical and operation parametres occurs simultaneously to evolution of their form factors therefore their sizes step-by-step decrease, expanding areas of usage of the given arrangements.

Fig. 1. Evolution of form factors of disk drives on hard disks

In rather short period of existence of personal computers, whose appearance in 1981 it is obliged to the invention by corporation of Intel of microprocessors in 1974 , disk drives on hard disks have transited path from the arrangements using magnetic disks in diameter of 8 inches, to disk drives with disks in 3,5 inches. And apparently from the circuit presented on fig. 1, the height of these arrangements and, therefore, their size even faster decreased.

However on it evolutionary process of the given accessories has not stopped. Really, now step-by-step transition from 3,5 on a form factor of disks in 2,5 inches is observed. Created originally for laptops, they step-by-step win the markets new to them, taking root already in some models of desktop computers. Moreover, with disks of the given format creators and users of server sector on which products traditionally there is an approbation of the newest processing techniques and architectures as with the price of novelties there it it is not necessary so sharply as in a consumer sector have become interested in disk drives.

"More and more users are interested today in servers and systems of data storage which physically would take less places and consumed less electric power, — John Monro (John Monroe), the vice-president of research organisation Gartner Dataquest marks. — New models of high-powered 2,5-inch hard disks allow to achieve more high speeds and bolshej dependability in corporate systems, reducing thus energopotreblenie and reducing the common sizes of systems. Transition to a new form factor for corporate systems is inevitable. Under forecasts Gartner, by 2007 in the multi-user environments 2,5-inch disk drives on hard disks" will dominate.

Fig. 2. Development of the market of 3,5 and 2,5-inch hard disks

In reply to requirements of the server market and according to tendencies of evolution of systems of an information storage in corporate systems company Seagate (Seagate Technology) has initiated developments of disk drives of a new generation with the improved technical and operation parametres.

Realising the given purposes, company Seagate has led mass interrogation of end users which has shown, that consolidation of server systems of an information storage, along with abbreviation of the place occupied with intelligence systems, are the important problems demanding more steadfast attention at level of firm. To solve these and many other things tasks, according to Seagate, transition of branch to a 2,5-inch platform of disk drives what it has been officially declared in May, 2003 at support of such companies as HP, Intel, Microsoft and of some other large players of the computer market will help.

As a result of considerable investments into research and development and the led researches company Seagate has presented recently Savvio (from Savvy + I/O, Savvy  — mind, ingenuity, I/O  — input/output) — the first-ever bar of 2,5-inch disk drives on hard disks of scale of firm with speed of rotation of a spindle of 10 000 turns in a minute. The given new drives of form factor SFF (Small Form Factor  — a small form factor) on a plan of their implementators in the near future will be applied in solutions of new type. These solutions will allow to create more compact systems of data storage fulfilling bolshee number of input/output operations in second and providing thus as much as possible high dependability.

Fig. 3. The disk drive on 2,5-inch hard disks Savvio

Disk drives on hard disks Savvio are perspective solution in the field of data storage for high density platforms, including new servers, arrays of data storage and blade-servers as these disk drives differ in the smaller sizes, smaller energopotrebleniem, therefore, and a smaller heat release, and also the minimum search time and the highest in branch dependability.

Disk drives on hard disks Savvio represent 2,5-inch disk drives with speed of rotation of a spindle of 10 000 turns in a minute. They possess a number of advantages in comparison with 3,5-inch hard disks with the same speed of rotation of a spindle. In particular, disk drives Savvio occupy on 70 % of less place, they on 400 gramme it is easier, on 40 % is more economic on energopotrebleniju, and the search time was reduced to 15 %.

As a result of implantation of the given new 2,5-inch disk drives corporate users save considerable financial assets. It is reached thanks to reduction of office square which have been taken away under the equipment, and also lowering of expenditures by the organisation of specialised premises (conditioning, usage of blocks of uninterrupted power supply etc .), cards for the electric power, etc. need to be added, that in many cases users of the systems created on the basis of new disk drives, receive additional profit at the expense of abbreviation of execution time of tasks.

Disk drives on hard disks Savvio ogranichenno are delivered now with one or with two slices and have size, accordingly, 36 Gbytes and 73 Gbytes (byte is gauged in billions) that is the most demanded sizes of similar arrangements in the majority of applications of scale of firm. Key parametres of disk drives Savvio are resulted in table 1.

Table 1. Key parametres of disk drives Savvio



Form factor (diameter of disks, a thickness), inches/mm

2,5 / 15

Size, a Gbyte

36,7, 73,4


U320, 2G FC, SAS

Speed of rotation, about/with

 10 000

Access time (Avg. Seek), a msec


Transition time (Tk-to-Tk), a msec

0,4 / 0,7

Transfer rate (Transfer Rate), Mb per second


Number of disks / heads, sht

1 / 2, 2 / 4

Time between failures (MTBF), hour

  1 400 000

Power of consumption (Idle Power), W

<5,1, Reading <8,0


In a construction of hard disks Savvio a number of original innovations which concern the high-speed controller improved, truncated aktuator is used, miniature 15 mm FDB the engine, hydrodynamic bearings, and also the improved built in algorithms and programs of rise of dependability of operation and diagnostics of faults (SMART, utilities) etc. Thanks to the inserted innovations average time of framing for refusal (MTBF) for the given arrangements makes under the statement of implementators of 1,4 million hours. By the way, unlike disk drives with traditional interfaces ATA and SATA where at time between failures testing there are working conditions, characteristic for typical desktop system, at an estimation of time between failures of disk drives Savvio the special technique uses. This technique consists in reception of results of dependability of the operation, grounded on round-the-clock (in a mode 7/24/365 — 7 days in a week for 24 hours within 365 days) the absolute loading of the arrangement imitating working conditions of system at firm.

Drives Savvio are planned to deliver with one of three interfaces accepted in sector of server solutions, including Serial Attached SCSI (SAS). SAS  — a new stage in interface SCSI development, providing considerably more high efficiency, flexibility and scalability of solutions. Characteristics of used interfaces with the given disk drives are resulted in table 2.

Table 2. Short characteristics of interfaces



2 Gbit/with Fibre

Serial Attached SCSI

Number of arrangements, sht


4 million

12 TO

Distance, m


 12 000


Double port




Full Duplex




Capacity, Mb




The protocol


Fibre Channel



Blade servers,

1U servers,


Arrays of memory

Arrays of memory,
Blade servers,

1U servers,


Parsing possibilities of interface SAS, it is necessary to mark, that recently companies Seagate Technology and LSI Logic have shown for the first time a transfer rate 3 Gb/with on first-ever 2,5-inch industrial Serial Attached SCSI the disk drives working on two-port controllers LSI Logic SAS1064. Demonstrating has taken place within the limits of the next Developer forum — IDF Spring 2004 (IDF  — Intel Developer Forum), taken place in San Francisco (California, the USA). Demonstrating in San Francisco became one more certificate of the successes reached in development SAS of solutions recently, and leading part Seagate and LSI Logic in advancement in the market of this new evolutionary processing technique in the field of data storage. Processing technique Serial Attached SCSI is characterised by high values of productivity, scalability and compatibility. It allows IT to managers to consolidate data storage at firm and thus considerably to cut the common expenditures.

The system shown in San Francisco, consisted from SAS a host of the adapter from company LSI Logic, handling data for the speed to 3 Gbit/with, and the 2,5-inch drive of scale of firm from Seagate. Presence of two ports has allowed to show the main distinction between SAS and SATA hard disks. At firms where high dependability is required, availability and productivity, presence of two ports is the key factor providing the common stable state of system and raising productivity of subsystems of direct-on-line (Direct Attached Storage).

"In the conditions of proceeding growth of requirements of firms in resources of data storage, solution Serial Attached SCSI from Seagate will allow IT managers to provide a necessary performance level and scalabilities for performance of applications with a considerable quantity of transactions on critical systems for business, — Jeff Lubbaka (Jeff Loebbaka), vice-president Seagate on marketing has marked. — the technological lead shown by us in many respects grows out of active efforts in the field of research and development. When Seagate, the leader in the field of SCSI disk drives on hard disks, has decided to develop the new interface, he has accessed to company LSI Logic. Application of chip Rapid Chip from LSI Logic will allow us to enter faster the market with new products, paternal, eventually, win ours OEM customers".

Thus and interface Serial Attached SCSI is the following step in development of the branch standard interface for storage devices. Processing technique SAS expands possibilities of solutions on the basis of interface SCSI (Ultra320) and is intended for usage in a new generation of workstations and servers on the basis of Direct Attach Storage, saving thus return compatibility at level of arrangements. And as physical level SAS of systems is compatible with SATA, users can select for the SAS systems either SATA, or SAS disk drives on hard disks, or to combine them. Processing technique SAS provides much more more a high speed and more ample opportunities for interconnection, saving thus the same functionality and dependability, as its predecessor — processing technique Ultra320 SCSI.

Company Seagate plans to release the first SAS disk drives in the autumn of 2004, expanding thus assortment of production which already includes solutions on the basis of Ultra320 SCSI, Fibre Channel and Serial ATA. In turn company LSI Logic has declared schedules to release the most complete in branch SAS set of controllers, expanders, a host of adapters and adapters ROMB and RAID.

It is expected, that hard disks Savvio will appear on sale in the end of the second calendar quarter 2004. Release of hard disk drives Savvio of form factor SFF and with interface SAS is planned for the third quarter 2004.

In article company Seagate substances have been used

Article is published in log Byte (

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