Advertisement
-
M Z-5600A
(5) DATA WRITE (DMA)
OIUlQO
- - ...
\ ........ _,' ..... - - - - - . . . ,
,.... -
-
- .... - -.\ __ ... _/,..
-
- -
-1f- --.,'-
...
...
Jr -
-
-
- -
......
"'i5ACi"a
-- --
...
...,\_--- . ./,...- ...... - '"'', . . . . -
-
-
J:--- --
~\
...
-
--
j
.....
-
~f-
- --
'"""·~
- ·- . . .
J r
-
...
-
- -
" - - ....1 ..... - - - -
-
-
....... \.... ....
J
...... -
-
- - - -
....
\
...
-
J,
....
-
-jf--
-
-
-
~
..........
_/.- - -- -
-
...
DATA
-------CJ--------CJ----
-
---c:J---jf-------c:)------
~
---- --- -
- - ---
-------- --- -- -
- !r- -- - - - --- ;_
-
~~
~~
~---.
~
~
~~--~
}~~
2-2. Transfer Method
DUAL-BUF transfer
BliF
I
(
RAll
)
(1) RAM
•
HDC program area
•
BUF 0, BUF 1 area
Eac~
BUF is a 1
sector
BUF.
--L
write execution
-!--J.-
t ime
At 2KB/Chip RAM, the maximum sector length
=
5128.
Each BUF transfers data
in
the
time
division system.
(2) HOST, BUF transfer rate
When data are transferred between 5" F XD and the
host,
the data are temporarily housed
in
the memory buffer
register,
which makes
the
transfer at an optional rate.
In multisector operations, the transfer
rate
between
the
host and buffer decides the sector
interval
(interleave).
(3) DUAL-BUF
When DUAL-BUF
is
used as HDC,
if
the DMA transfer
rate at
the
host side
is
slower than that of the disk,
it
can
be transferred. With multisector mode transfers, a
1
sector
interval
-transfer can be executed at different transfer
rates
from the
host.
•
lt can
be
transferred if the DMA
transfer rate is slower
than
that
of
the
disk
.
• The host's burden
is
reduced.
•
The
host's cycle steal and high-priority process can
interrupt.
• With multisector mode, process dificiency does not
decline
.
(e .g.) Read Data
(disk~
host)
disk transfer rate
5Mbit/s (1.6Ms/byte)
host transfer
rate
3 .2Ms/byte
SEC
TOR! DATA
BUF 0
I
DI
S
K
-
auro
BU
F
I
S
ECTOR! DATA
BUF
O
~ HOS
T
J
S ECTOR2
DATA
D
I
S
K
_,.
BU
rt
DMA transfer time chart
SECTORS
DATA
I
D
I
S
K
~
BUF
O
S
ECTOR
2
DAT
A
BUF
I
- HOS
T
a) SINGLE MODE, DISK
-
HOST
b)
SINGLE MEMORY (BUF)
-
·
HOST
CL<
HRQ
HLDA
PW..
S
£0
SEC
TOR 4
S EC
TORB OAT A
BUF
O
-~>
HO
S
T
S EC
TOR4
DATA
DI
S
K
-
BUFI
ADR-STI=~~~~
ADI\0-1
ADA£
IlEA()
WR
I
TE
ii="ifilj
c) SINGLE MEMORY (BUF)- DISK
CLK
HRQ
HLOA
~m'
-------~-+~~--------+---------~--------~-----
Al>ft-STB=====~st======t===>~~~====t===
TCAR
ADRO
-1
-
2
-
Advertisement
