Compaq MSB900L user manual Digital-Logic Ag, MSB900/L Detailed Technical Manual

DIGITAL-LOGIC AG MSB900/L Detailed Technical Manual V1.0

CMOS Map continued...

Location	Description
	Byte 3
22h	Bits 7-6	= Reserved
	Bits 5-0	= Upper 6 bits of Write Precompensation
	Byte 4
23h	Bits 7-0	= Number of Heads
	Byte 5
24h	Bits 7-0	= Sectors Per Track
25h - 2Ah	Custom Drive Table 1
	These 6 Bytes (48 bits) contain the following data:
	Cylinders			10bits	range 0-1023
	Landing Zone			10bits	range 0-1023
	Write Precompensation			10bits	range 0-1023
	Heads			8bits	range 0-15
	Sectors/Track			8bits	range 0-254
	Byte 0
25h	Bits 7-0	= Lower 8 bits of Cylinders
	Byte 1
26h	Bits 7-2	= Lower 6 bits of Landing Zone
	Bits 1-0	= Upper 2 bits of Cylinders
	Byte 2
27h	Bits 7-4	= Lower 4 bits of Write Precompensation
	Bits 3-0	= Upper 4 bits of Landing Zone
	Byte 3
28h	Bits 7-6	= Reserved
	Bits 5-0	= Upper 6 bits of Write Precompensation
	Byte 4
29h	Bits 7-0	= Number of Heads
	Byte 5
2Ah	Bits 7-0	= Sectors Per Track
2Bh	Boot Password
	Bit 7	= Enable/Disable Password
		0	=	Disable Password
		1	=	Enable Password
	Bits 6-0	= Calculated Password
2Ch	SCU Password
	Bit 7	= Enable/Disable Password
		0	=	Disable Password
		1	=	Enable Password
	Bits 6-0	= Calculated Password
2Dh	Reserved
2Eh	High Byte of Checksum - Locations 10h to 2Dh
2Fh	Low Byte of Checksum - Locations 10h to 2Dh
30h	Extended RAM (kB) detected by POST - Low Byte
31h	Extended RAM (kB) detected by POST - High Byte
32h	BCD Value for Century

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