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METHOD:
(cont .)
SUBROUTINES:
Write-with-Verification
Calling sequence:
BRM
05
*QSYS
FDT
The write-with-verification operation is identical to the write operation, ex-
cept that after each output to the RAD, the specified sector is input and com-
pared, word by word, with the output buffer.
The X2 buffer is used for the
comparison buffer.
This option is used during SYSGEN, when X2 is not active.
The user is cautioned against using this option, since X2 or BO might be in-
advertently destroyed by doi ng so.
Position
Ca
II
i ng sequence:
LDA
BRM
06
=
RAO word address
*QSYS
FOT
Position the file whose number is specified in the fourth word of the file de-
seri pti on tab!
e
at
the
addieSS speC i fi ed; then open
the
fil
e. 'vVords two and
three are ignored.
This option is used by the system search routines to position the S file randomly,
in accordance with addresses specified in the D file.
RDISC/WDISC
Ca
II
i ng Sequence:
LOA
LDB
BRM
Return
= Interlace control word
= RAO Sector
RDISC/WOISC
Upon return, A wi
II
be
cI
ear if the I/O operation was performed successfu
II
y.
Otherwise, A will contain a lone l in bit 1, and, if part or all of the specified
disc area is file protected, A will contain a lone l in bit 5.
The RAD handler util izes the 11 EOM/SKS instructions that are initialized
during SYSGEN or bootstrap to correspond with the channel to which the RAD
is assigned.
The file is always assumed to be no. 1 (unit address
=
026/066).
The handler initiates the read/write operation and checks for a coupler or chan-
nel error.
If no error is detected, the handler returns with (A)
=
O.
Otherwise,
the attempt is repeated twice.
Upon the third failure, A, is set to lone l , and,
. .
•
•
I
•
if a file-protected test proves true, AS is also set.
The handler has
the
following additional characteristics:
1.
Uses interlace, but not interrupts.
63
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