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PRODUCT DESCRIPTION
SubsystemConfiguration
Dual Drive Support
Two drives may be accessed via a common interface cable, using the same range of I/O addresses. The drives are jumpered as device 0 or 1 (Master/Slave), and are selected by the drive select bit in the
Device/Head register of the task file.
All Task File registers are written in parallel to both drives. The interface processor on each drive decides whether a command written to it should be executed; this depends on the type of command and which drive is selected. Only the drive selected executes the command and activates the data bus in response to host I/O reads; the drive not selected remains inactive.
A master/slave relationship exists between the two drives: device 0 is the master and device 1 the slave. When J50 is closed (factory default, figure
Cable Select Option
CSEL (cable select) is an optional feature per ANSI ATA specification. Drives configured in a multiple drive system are identified by CSEL’s value:
– If CSEL is grounded, then the drive address is 0.
– If CSEL is open, then the drive address is 1.
Jumper Location / Configuration
Darkened jumper pins indicate
J U M P E R C ON F IGU R AT ION | J 5 | 0 | J 4 8 | J 4 6 | J 4 4 | J 4 2 | |
M a s te r / S la v e |
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O nly d r i ve i n | s i n g le d r i ve s ys te m * | C |
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M as te r d ri ve i n d u a l d r i v e s ys te m * | C |
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S l a ve d r i ve i n du a l d ri v e s ys te m | O |
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C a bl e S e l e c t |
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D i s a b le d * |
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E n a b le d |
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| C |
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C y li n de r Li m i ta ti o n |
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D i s a b le d * |
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E n a b le d |
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F a c to ry R es e rve d |
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F a c to ry R es e rve d |
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Ke y * = D e fault | C = C lo se d (j um p er in s tal le d) | O = O pen (no j um p er in s tal le d) | |||||
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Figure
PCBA Jumper Location and Configuration
CylinderLimitationJumperDescription
On some older BIOS', primarily those that
2 – 5