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ASM 421 Technical Description
6GT2 097-3AH00-0DA2
– 44 –
RD: 03/02
6GT2 002-0DA00
ASM 421 / V.24
Subject to change without notice!
6GT2 002-0DB00
ASM 421 / RS422
6GT2 002-0DC00
ASM 421 / TTY
J31069-D0142-U001-A0-7618
3.4.16
LOAD/MOVE
The LOAD and MOVE commands are optional file handler commands. These allow access times to MDS
data following a cold start or restart to be optimized. The time spent reading a directory is eliminated for the
first MDS to enter the field. The LOAD/MOVE commands are only meaningful if the same directory is
present in all data carriers in the system.
LOAD:
A protected directory is transmitted from the user to the ASM. This command can be issued by the user
after the RESET, to load the old directory into the ASM. When the first MDS to arrive is processed, the
directory does not then need to be read in from the MDS. The time for the directory to be read does not
need to be considered when designing the system. Especially important in dynamic operation: the first
MDS to arrive after a RESET can immediately be processed at full transport speed.
The file handler checks the directory transmitted by the ‘L’ command for plausibility. Check sums and di-
rectory data must correspond. If this is not the case, the user receives the error message D007 in the
acknowledgement. The file handler continues to function normally despite this error message. The direc-
tory transmitted by the ‘L’ command will be rejected. The file handler reads the directory from the first MDS
to arrive.
Telegram to the file handler:
’L’
CC CI ADB DBN DBL
00
xx
0000
ADB
DBL Length
0
1
2/3
4
5
6/7
8/9
10
11/12
13 ...
’I’
0001
DIR + FAT
Data protected in user control by the MOVE command
Data
The data block count is calculated from the length of the data
(bytes 11/12). It must be calculated correctly by the user (see
example in section 3.4.4).
’L’
CC Status ADB DBN DBL
00
xx 0000
ADB
00
0
1
2/3
4
5
6/7
8/9
10
00
0001
Acknowledgement:
Warning:
A RESET command deletes the directory stored in the ASM, i.e. the complete
directory will be read from the next MDS following a RESET command.
An error message from any command can delete the directory stored in the ASM
as well (see chapter 7).
In applications using the LOAD/MOVE commands, a LOAD command must
therefore be programmed after each RESET command and after each error
message.