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CHECKING FEATURES
Customer-tailored e r r o r checking features include:
Odd parity check on read-write transfers
Memory access check
Clocking check
Address confirmation check
Longitudinal parity word check
Read-after-write check
Each word on the disc file contains parity plus an additional check word per record. If a word
parity e r r o r should occur on reading, program reconstruction is possible through the use of the
check word.
MRADS INSTRUCTIONS
The PRF, RRF, RRD, WRD, WRF, and RAW instructions must be preceded by the SEL P in-
struction, which selects the specific controller P.
The general format of these instructions
utilize the following conventions:
F
=
mass random access file number (0 to 3).
K
=
MRADS file number (0 to 3), test and branch instructions.
M
=
memory location of data.
N
=
number (1 through 16) of 64-word records to be transmitted from core storage to disc
storage o r vice versa.
P
=
controller assignment (plug number).
Note: File number (F) is normally recorded in column 20 of the GAP coding sheet.
-
Mnemonic
Operand
Index
Time
Description
Oper. Code
Address
Word
-
Microsec.
P R F
F
36
Positions a r m of MRADS unit to receive or transmit
a specific record.
(MRADS Address)
Contains actual address (in octal) of the selected
MRADS.
F
36
READ FROM MRADS UNIT.
Reads N records from
MRADS file F, into memory, starting a t location M.
WRF
N
F
36
WRITE ON MRADS UNIT.
Writes N records on
MRADS file F from memory, starting at location M .
F
36
READ AFTER WRITE CHECK.
A parity check i s
made on all words of a record(s) transferred to the
file.
VIII-3
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