TITLE
    Macintosh EIDE Drives: Drive Specifications
Article ID:
Created:
Modified: 		24217
11/14/97
1/18/00
TOPIC

    What are the specifications that an EIDE drive must meet or exceed to be used in an Apple product?

DISCUSSION

    It is important to remember that Apple qualifies several different drive vendors for a particular configuration, so the specifications are going to vary from vendor to vendor. Apple may also switch vendors periodically during the life of a product usually due to cost and availability of drives at the time of manufacturing. Since we have no way of knowing which drives the customer would actually receive, the specifications here are the general specifications for the drives.
    Performance and Functional Specifications
    Average Access Time less than or equal to 16ms
    Read Cache greater than or equal to 32KB
    Write Cache On or Enabled
    Interface Burst Transfer Rate greater than or equal to 8MBytes/sec, PIO Mode3
    Minimum Sustained Data Rate greater than or equal to 2MBytes/sec
    Time to Ready from Power On less than or equal to 10 sec typical
    Mean Time Between Failures greater than or equal to 300,000 Power On Hours
    Start/Stop cycles greater than or equal to 40,000
    Acoustics - Idle less than or equal to 33dBA, 38dBA max. No discrete tones
    Acoustics - Seeking less than or equal to 39dBA, 42dBA max.
    No nonrecoverable errors allowed.
    AutoReallocation of bad blocks during Writes and Reads.     		.

    Another important factor to remember is that these specifications are Apple's requirements when we qualify a drive vendor. These specifications are the requirements for the drive only. When the drive is plugged into a computer you also have to take into account other factors that may affect the overall drive performance that are not necessarily specific to the drive. This includes things like other devices attached to the computer, drivers and the type of data being transferred.

Document Information
Product Area: Peripherals
Category: Magnetic Storage Devices
Sub Category: Hard Disk; General
Keywords:

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