A Support For Large Disk Drives; Extended Translation (Using Ms-Dos 5.0; When To Enable Extended Translation - Adaptec AHA-1510A Series User Manual

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Support for Large
Disk Drives

Extended Translation (Using MS-DOS 5.0)

All current versions of DOS are limited to 1024 cylinders per drive.
The standard translation scheme for SCSI host adapters, using
64 heads and 32 sectors, provides a maximum accessible capacity of
1 GByte. As disk drives have recently grown beyond 1 GByte in for-
matted capacity, they have run up against the DOS 1024-cylinder
limit. To continue its support for all SCSI disk drive capacities under
DOS, Adaptec has included an extended translation scheme for
AHA-1520A/1522A host adapters. This feature supports disk drives
as large as 8 GBytes under DOS.

When to Enable Extended Translation

Extended translation is disabled by default. Use extended transla-
tion for > 1 GByte hard disks under DOS. Use standard translation,
not extended translation, on drives formatted with two or more par-
titions for different operating systems. Partitions for NetWare can be
larger than 1 GByte when using standard translation. For instruc-
tions on enabling extended translation, see Chapter 2, Host Adapter
Configuration.
Caution:
Be sure to back up your disk drive before you
change the translation method on a disk drive. All data
is erased when you change from one translation scheme
to another.
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AHA-1510A/20A Series User's Guide
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Stock Number: 510400-00, Rev. C
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A A Print Spec Number: 491842-00
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Current Date: 11/18/94
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ECN Date: 11/29/94
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