History (1988): Siemens 380 to 765MB Full-Height 5.25-Inch HDDs

Only three companies succeeded in producing over 750MB unformatted on a full-height 5.25-inch HDD.

Maxtor put the level high: 760MB. Siemens, also finally defunct HDD maker, reached 777MB on its 5000 Megafile.

On October 26, 1986, Micropolis announced a new 1560/1580 series with especially the 1568-15 model with ESDI interface for $2,295 and the 1588-15 model with SCSI interface for $2.395, both of them with an unformatted 765MB capacity (prices are for quantities of 2,000). The formatted-capacities are 676 and 668MB.

These two devices have an average 16ms access time and an average 30,000-hour MTBF. Data is transferred at 15-Mhz data rate, which means data transfer rates of 1.88 MB/s (with the ESDI interface) or 4.0MB/s (with synchronous SCSI interface).

For users of the older 8.9 or 14-inch form factor drives, the 1560/1580 series, that store from 380 to 765MB, offer a way to develop lower cost, smaller system without sacrificing capacity or performance.

The sealed head-disk assembly contains all the moving parts, including a single-piece rotary head positioner, 15 read write heads, 8 5.25-inch platters and spindle motor. The system has a rating of 15 minutes MTTR.

The series will be available during 2Q88.

This article is an abstract of news published on the former paper version of Computer Data Storage Newsletter on issue ≠1, volume ≠1, published on February 1988.