This first-ever disk drive was initially cancelled by the IBM Board of Directors because of its threat to the IBM punch card business but the IBM San Jose laboratory continued development until the project was approved by IBM's president. Patent 3,503,060 from the RAMAC program is generally considered to be the fundamental patent for disk drives. The 350 was officially withdrawn in 1969. The IBM RAMAC 305 system with 350 disk storage leased for $3,200 per month. Several improved models were added in the 1950s. An access mechanism moves a pair of heads up and down to select a disk pair (one down surface and one up surface) and in and out to select a recording track of a surface pair. Data transfer rate is 8,800 characters per second. It has fifty-two 24- inch (610 mm) diameter disks of which 100 recording surfaces are used, omitting the top surface of the top disk and the bottom surface of the bottom disk. The 350 stores 5 million 6-bit characters (3.75 MB). Its design was motivated by the need for real time accounting in business. The first engineering prototype 350 disk storage shipped to Zellerbach Paper Company, San Francisco, in June 1956, with production shipment beginning in November 1957 with the shipment of a unit to United Airlines in Denver, Colorado. RAMAC stood for "Random Access Method of Accounting and Control". Simultaneously a very similar product, the IBM 355, was announced for the IBM 650 RAMAC computer system. The IBM 350 disk storage unit, the first disk drive, was announced by IBM as a component of the IBM 305 RAMAC computer system on September 14, 1956. RAMAC mechanism at Computer History Museum
Here, the current industry standard terms, hard disk drive (HDD) and floppy disk drive (FDD), are used. IBM uses many terms to describe its various magnetic disk drives, such as direct-access storage device (DASD), disk file and diskette file. By 1996, IBM had stopped making hard disk drives unique to its systems and was offering all its HDDs as an original equipment manufacturer ( OEM). IBM always offered its magnetic disk drives for sale but did not offer them with original equipment manufacturer (OEM) terms until 1981. IBM manufactured 8-inch floppy disk drives from 1969 until the mid-1980s, but did not become a significant manufacturer of smaller-sized, 5.25- or 3.5-inch floppy disk drives (the dimension refers to the diameter of the floppy disk, not the size of the drive). Few products in history have enjoyed such spectacular declines in cost and physical size along with equally dramatic improvements in capacity and performance. Disk drive performance and characteristics are measured by the same standards now as they were in the 1950s. The basic mechanical arrangement of hard disk drives has not changed since the IBM 1301. Both the hard disk drive (HDD) and floppy disk drive (FDD) were invented by IBM and as such IBM's employees were responsible for many of the innovations in these products and their technologies. IBM manufactured magnetic disk storage devices from 1956 to 2003, when it sold its hard disk drive business to Hitachi.
0 kommentar(er)
