Request (Physical) Disc Address - HP 9800 Series Service Manual

HP 9895A Disc Memory Command Set
A-21
Request (Physical) Disc Address
Type:
Purpose:
Description:
HP-IB Sequence:
ATN
IPOl~DDRSI
PrImary
ATN
I PlO~DDRSI
Pnmary
Status:
Parallel Poll:
Sense.
The 9895A returns bytes indicating the physical cylinder
on which the head actuator is positioned. This is useful for
calculating the number of invisible tracks between the
outer-most track and the current track. This is done by
subtracting the physical cylinder address from the target
cylinder address.
After receiving the request (physical), the 9895A returns
two bytes containing the physical cylinder address, one
byte containing the head address and one byte of zeros.
Request (Physical) Disc Address
ATN
I
P1101100
I
Secondary
P
P
D
10100
1
Opcode
Send Address
ATN
P
P110lOOO P
I
Secondary
I
D
Cylinder Address
ATN
P
P
I
PlO11l11
1
E
Unlisten
I
00000000 I
See Request (Logical) Address.
See Request (Logical) Address.
EOI ATN
P
~
I
PlOl 11 11 I
Unlisten
Head