Status Register 1 - IBM 5150 Hardware Reference Manual

Table 16.
Status Register
2
BIT
NO. NAME
SYMBOL
07
-
­
06 Control Mark CM
05
Data Error in DO
Data Field
04
Wrong Cylinder WC
03 Scan Equal Hit
SH
02 Scan Not
SN
Satisifed
01
Bad Cylinder BC
00
Missing Address MD
Mark in Data
Field
DESCRIPTION
Not Used. This bit is always 0 (low).
During execution of the Read Data or
Scan command, if the FDC encounters
a sector which contains a Deleted Data
Address Mark, this flag is set.
If the FOC detects a CRC error in the
data then this flag is set.
This bit is related with the NO bit, and
when the contents of Con the medium
are different from that stored in the
ID Register, this flag is set.
During execution of the Scan command,
if the condition of "equal" is satisfied,
this flag is set.
During execution of the Scan command,
if the FDC cannot find a sector on the
cylinder which meets the condition, then
this flag is set.
This bit is related with the NO bit, and
when the contents of C on the medium
are different from that stored in the ID
Register, and the content of C is FF, then
this flag is set.
When data is read from the medium, if
the FDC cannot find a Data Address
Mark or Deleted Data Address Mark,
then this flag is set.
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