Configuration and Jumper Options
The interface allows up to two drives (a Master) and one Slave) to be attached to the IDE bus. This is selected by jumpers W1 and W2, as follows:
in in (Used for 2112A only) Drive emulates both Master and Slave
(factory default for 2112A)
in out Drive is Master, Slave is present
out in Drive is Slave
out out Drive is Master (factory default for 2105A)
The capacity of the drive may exceed the capacity that the host can access. This limitation stems from the communications link between the DOS and the BIOS. A typical limit is 1024 cylinders, 16 heads, and 63 sectors. For optimum use of the following options, the BIOS may need to be modified.
Drive is Master, Slave is present:
Specifies the Master drive (Drive 0) when two 2105A/2112A drives are used in a system. The other drive is Slave.
Drive is Slave:
Specifies the Slave drive (Drive 1) when two 2105A/2112A drives are used in a system. The other drive is Master.
Drive is Master:
Specifies the Master drive (Drive 0) when one 2105A/2112A drive is used in a system.
For the 2105A Drive only:
The 2105A drive is configured on power-up to have 63 logical sectors per track, 16 logical heads, and 1084 logical cylinders.
For the 2112A Drive only:
Drive emulates both Master and Slave:
Specifies that one 2112A drive can emulate both the Master drive (Drive 0) and the Slave drive (Drive 1). This option allows for existing host systems to utilize the full capacity of the drive.
When the 2112A drive is configured as both the Master and the Slave, the Master's (Drive 0) capacity is set to 1084 logical cylinders, 16 logical heads, and 63 logical sectors. This setting yields 528,482,304 bytes. The Slave's (Drive 1) capacity is set to the remaining storage on the disk drive.
For this configuration, the recommended drive type setting in the computer's CMOS memory is as follows:
Drive 0: 1024 logical cylinders, 16 logical heads, 63 logical sectors.
Drive 1: 1010 logical cylinders, 16 logical heads, 63 logical sectors.