Siemens MOBY FC 56, Technical Description

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Introduction
1-3
FC 56
J31069-D0155-U001-A0-7618
1.1 Basic Information about the “Filehandler”
To give yourself a better idea of how the MOBY filehandler works, think of it as a
floppy disk system.
MOBY Filehandler Floppy Disk System
MDS:
Data is stored electronically
in the MDS on a memory
chip (RAM or EEPROM).
Floppy-Disk:
Data is written magnetically
on a floppy disk.
SLG
:
The SLG modulates the
data stream arriving from
the ASM and demodulates
the data stream arriving
from the MDS.
The MDS must lie within the
transmission window of the
SLG. The size of the trans-
mission window depends on
the MDS/SLG configuration.
The MOBY interface module
(ASM) provides the user in-
terface. A USART module
on the ASM produces the
serial data stream for the
SLG.
Floppy-Gerät:
The floppy drive converts
the data impulses arriving
from the PC into a write
string for the read/write
head (or vice versa)
The floppy disk must be po-
sitioned very exactly over
the read/write head as this
generates only very small
magnetic fields.
A PC controls the floppy
drive and exchanges data
with it via an interface. The
coding and decoding of the
data takes place in a floppy
controller in the PC.
As with a floppy disk system, the filehandler also accesses data using logical file
names, not physical memory addresses. This in turn requires that the files are
created on a formatted (completely erased) data carrier. The data relating to a file
can then be processed by the appropriate command, e.g. READ, WRITE, DELETE
etc.