Hard Disk Drive

The hard disk has short and fascinating history. In 24 years it has evolved from a monstrosity with fifty two-foot diameter disks holding five Bytes (5,000,000 bytes) of data to today's drives measuring 3 / 12 inches long and an inch long (and smaller) holding 400 Bytes (400,000,000,000 bytes / characters). Here, the short history of this wonderful device.

Before the disc, there was drums ... In the 1950 substantiated Engineering Research Associates in Minneapolis the first commercial magnetic drum storage unit for the U.S. Navy, ERA 110: e, it can save one million bits of data and retrieve a word in 5 thousandths of a second. In 1956 IBM invented the first computer disk storage system units units 305 RAMAC (Random Access Method of Accounting and Control). This system could store five Bytes. It had fifty 24-inch diameter disks!

In 1961, IBM invented the first hard drive with an air of headlines and in 1963 they introduced the removable disk pack drive. In 1970 the eight inch floppy drives were introduced by IBM. My first disk drives were made by Sugar, who was one of the "dirty dozen" who left IBM to start their own business. In 1981 two Sugar 8-inch floppy drive with enclosure and power supply cost me around $ 350.00. They were my second computer. My first computer was not running at all. In 1973 IBM shipped the model 3340 Winchester sealed hard disk, the predecessor of all current hard drives. The 3340 had two spindles, each with a capacity of 30 Bytes, and the term "30/30 Winchester" was thus invented.

Seagate ST4053 40 Byte 5 1 / 4 inch, full height "clunk" With the ST506 interface and voice coil Around the 1987th My price was $ 435.00. In 1980, Seagate Technology introduced the first hard disk drive for microcomputers, the ST506.It was a full height (twice as high as the current 5 1 / 4 "drives) 5 1 / 4" drive with a stepper motor, with 5 Mbytes. My first hard drive was a ST506. I can not remember exactly how much it costs, but that plus his cage, and so much more than a thousand dollars. It took me three years to fill the drive. Also in 1980 Phillips was the first optical laser drive. In the early '80s, the first 5 1 / 4 "hard disks with voice coil actuators (more on this later) began shipping in volume, but Stepper Motor Drives continued in production in the early 1990s. In 1981, Sony sent the first3 1 / 2 "floppy drive.

In 1983 Rodmen made the first 3.5 inch rigid disk drives. The first CD-ROM drives were shipped in 1984, "Grolier's Electronic Encyclopedia," followed in 1985. The 3 1 / 2 "IDE drive started its existence as a drive a plug-in expansion board, or "hard card." Harddisken card included in the controller, which in turn evolved into Integrated Device Electronics (IDE) hard disk if the controller were incorporated into the printed circuit board in the bottom of the disc. Quantum made the first hard card in 1985.

In 1986, the first hard 3 / 12 "disks with voice coil actuators were introduced by Conner in volume, but half (1.6") and full height 5 1 / 4 "drive lasted several years. In 1988 Conner introduced the first empty high 3 1 / 2 "hard drives. In the same year Prairies shipped the first 2 1 / 2 "hard drives.

In 1997 Seagate was the first 7200 RPM, Ultra ATA hard drive for desktop computers, and in February this year the first 15,000 RPM hard drive, the Cheetah X15. Milestones for IDE DMA, ATA/33 and ATA/66 drives follows:

1994 DMA Mode 2 at 16.6 MB / s

1997 Ultra ATA/33 at 33.3 MB / s

1999 Ultra ATA/66 at 66.6 MB / s

IDE Hard Disk Drive:

Integrated Drive Electronics (IDE) hard drives have existed for some years. Prior to these drives, hard drives were connected to a PC motherboard via an expansion board, known as a hard disk controller. Have driven most of the mechanical stuff and performed basic electronic / servo functions; controller told in detail what to do. The development of IDE hard drive moved the majority of electronics and firmware (low-level software on a chip) from the controller to a pressure plate on the drive itself. In the process, a buffer vary / cache memory is added to electronics to accelerate the process of reading and writing disk data. Powered getting "smarter." Total expenses went down and performance went up.

A much simpler board, commonly known as an IDE controller, interface model, IDE hard disk to the motherboard bus. The term IDE controller is misleading. It is actually nothing more than a bus interface and an interface connector and IDE cable goes to the drive. The actual controller is on the drive. In most cases where a computer, says it has a problem with the hard disk controller, it has a problem with the electronics on the drive. Subsequently IDE controller expansion board electronics and the connector to run the cable have been incorporated into most motherboards. Most of these motherboards have two IDE interfaces - one primary and one secondary - each of which can support two IDE devices. The term Integrated Drive Electronics (IDE) is owned by Western Digital. Other companies such as Maxtor, Quantum, and Seagate, uses the term ATA (AT Attachment). IDE and ATA is the same thing. Several standards were subsequently developed to improve the IDE drive and incorporate other devices such as CD-ROMs, which can operate off IDE: Enhanced IDE (EIDE), ATAPI (ATA Packet Interface), Ultra-ATA, etc. days , most hard drives designed for PCs is ATA/66 drive (ATA/100 is probably just around the corner). These drives are using Bus Mastering and Direct Memory Access to transfer data back and forth between the drives and computer memory with burst speeds up to a theoretical 66 megabytes per second (MBS) without going through the processor. Older ATA/33 (Ultra DMA) driver do the same at 33 Mobs. Many of the current motherboards still have ATA/33 or even older IDE interface. Most ATA/66 drives will work on the older IDE interface, but obviously not as fast.

How a Hard Works:

The purpose of this article is to provide just the right balance between technical details to give a good insight into the innards of a hard drive, and how, if largely operate without burdening the reader with excessive technical details.

HARD DISK assembly. A hard disk consists of a motor, spindles, and drums, read / write heads, actuator, frame, air filter, and electronics. The frame mounts the mechanical parts of the drive and is sealed with a cover. The closed part of the effort is known as the hard disk assembly or HDA. Drive electronics usually consists of one or more printed circuit boards mounted on the bottom of the HDA.

A main course and can be visualized as being similar to a recording and playback head on an old phonograph, except the data structure in a disk is arranged in concentric circles instead of in a spiral, as in a phonograph record (or CD-ROM). A hard drive has one or more courts, each court usually has a head on each of its pages. The Platters in modern drives is made of glass or ceramics, to avoid adverse thermal properties of aluminum dishes found in older drives. A layer of magnetic material is deposited / sputtered on the surface of drums, and in most of the hard drives I've dissected the shiny, chrome-like surfaces. The Platters are mounted on spindles which are in possession of the powerful engine. Most current IDE hard drives spin at 5400, 7200 or 10,000 RPM and 15,000 RPM drives are emerging.