Ampex Alar

1985Ampex Alar

20 years of attempted usage of plated metal media in disk drives ultimately led to the abandonment of this technology.
Ampex spectacularly failed in the mid-1980s.
DEC in the late 1980s with its RA90 family was the most successful (and last) example of the technology's application

Why its important
Ampex in 1979 with its plated Alar media was leading the industry transition from oxide to metal film media, achieving design wins with a number of companies including but not limited to Rodime's R0352 (3.5"), some IMI models, and was being designed into Maxtor's XT1000 (high performance 5.25"). By July 1984 Ampex had shipped 1 million disks, but this particular variation of metallic media proved unsuitable due to excessive field failures.

Plated media quality in the end turned out to be unsuitable for volume production and all adopters of Alar either failed or were required to recall their products and replace the plated media with sputtered media

In June 1985 Ampex Alar production ceased
Nonetheless,in 1988 the DEC board approved a $400M investment for the RA9X family, initially including the RA90, a 9-inch plated media device. Plating was chosen over the sputtering because the diameter was believed to be too large for economic sputtering. The last model was the 5¼-inch RA92 introduced in 1992. DEC repurposed their Tempe Arizona printed circuit board plant to make the plated disks. Unlike many of the earlier attempts DEC used an electrolytic plating process. DEC was the last company to use and one of the few successful users of plated media in a hard disk drive; interestingly, DEC with its RF08 circa 1969 was one of the first users of plated media in a hard disk drive.

Additional Information
"Ampex Disk Media Placed on Block, Say Tag $20M-$30M," Electronic News, Dec 9, 1985

Provenance note: Version 9 of this article was deemed "not ready for review" at the Computer History Museum' s Storage SIG meeting of June 20, 2012.

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