EF51R Solid State Disk Drive
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| EF51R | |
| Manufacturer: | Digital Equipment Corporation | 
|---|---|
| Drive Controller(s): | all DSSI Controllers | 
| Capacity: | 107 Mbytes (formatted) | 
| Transfer Rate: | 4.0 Mbytes/sec | 
| Average Access Time: | 0.25 msec | 
| Start Time: | < 2 min | 
| Physical Size: | 5.25" full height | 
The EF51R is the smallest drive of DEC’s first generation of solid state disks, packaged in a full-height, 5 1⁄4-inch form factor. The EF51R ISE provides non-volatility of data by a data retention system including:
- Power sensing logic
 - An internal winchester magnetic disk drive
 - A battery to power the EF51R while dumping data to the winchester disk
 
Apart from the DSSI interface, the EF51R disk drive is identical to the EZ51R Solid State Disk Drive.