HP 9800 SERIES - Request (Logical) Disc Address

A-20 HP 9895A Disc Memory Command Set
Request (Logical) Disc Address
Type: Sense.
Purpose: The 9895A returns bytes indicating the current target ad-
Description:
HP-IB Sequence:
ATN
I
P01~DDRSI
Primary
Listen
ATN
r10~DDRSI
Pnmary
Talk
Status:
Parallel
Poll:
dress. This command is used to determine the address of
the offending sector after a data error has occurred.
Following reception of
the appropriate command sequ-
ence, the 9895A returns four bytes indicating the current
target sector. This includes two bytes of target cylinder
address,
one byte of target head address and one byte of
target sector address.
Request (Logical) Disc Address
ATN
Pll01000
I Secondary I
ATN
I Pll01000 I
Secondary
P
P 10100
D I Opcode I
Send Address Command
P
P
D
Sector I
No errors.
Sl - 0
Cylinder Address
ATN
P
~ I P1011111I
Untalk
Stat 2 - Unchanged
DSJ -0
EOI
ATN
P
~ I P0111111I
Unlisten
Head
If less than the specified number of bytes is accepted by the
HP-IB controller, the parallel poll response will be re-
enabled by the Untalk command.
An extra byte (the value of 1) tagged with an EOI will be
sent if the controller requests more than the specified
number of bytes. However, this request is not necessary
for normal operations.