beautypg.com

Rana Systems Elite Series User Manual

Page 319

background image

ELITE SERIES USER MANUAL

APPEN. B - DOS NOTES

the desired track and nothing else.) When a “no

Operation” call is made to the enhanced RWTS,

and the sector number in the RWTS parameter list

is set to $FF, a “formatting error” ($08) will

be returned and the carry flag set. This is a

way for the application program to determine

whether or not an enhanced DOS is currently in

use since a non—enhanced DOS would not care

about the sector number during a “no operation”

call.

The enhanced DOS will return the error condition

without selecting any drives or performing any

seeks. in addition, the [AY] register pair will

be returned pointing to the base address of the

drive configuration table located within the

enhanced DOS.

The configuration table is 28 bytes Long, pro-

viding a one byte entry for each of the 4 drives

per 7 slots of controller cards possible. The

entry at [AY]+$00 is for slot 1 drive 1,

[AY)+$01 is for slot 1 drive 2, [AY]+$1A is for

slot 7 drive 3, and [Ay]+$1B is for slot 7 drive

4.

P a g e B - 4