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THE CONTROLLER SELECTOR
Data Register (21 bits, no abb., N)
The controller selector data register contains the data being transferred between the controller
selector and the data communications processor.
Address Register (15 bits, no abb., N}
The controller selector address register contains the address of the next memory location to be
accessed by the controller selector.
PARITY NETWORK (21 bits, no abb .. N)
Although it is not shown on the block diagram (for simplicity), there is a parity network in the
data communication processor. There are two outputs from the parity network, one for character
parity and one for word parity.
Either output may be tested to check the data. The appropriate
output is automatically sent to a buffer channel when information is transmitted.
The parity networks are attached to the B register and consist of a word parity network and a
character parity network.
Each time a word is brought into the B register, the word parity
network will generate correct parity on it.
At the same time proper character parity will be
generated on bits 1-6 of the B register. The input to the word parity network consists of the 18
bits of the B register, the control bit 1 and control bit 2 flip-flops. The output of the word parity
network is bit 21 and is used with the word buffer and computer interface units. The inputs to
the character parity network are bits 1-6 of the B register and the control bit 1 and 2 flip-flops.
The character parity is used almost exclusively for generating correct parity on 8 level Teletype
characters.
HARDWARE LOAD AND PAPER TAPE READER
The DATANET-30 has as standard equipment a 300 cps photoelectric paper tape reader and a bin
to contain a 300 foot loop of paper tape. The hardware load function, when initiated, will search
the tape for a "begin hardware-load" character, and then load the memory with data as specified
by the characters punched in the paper tape. An "end hardware-load" character will automatically
transfer control to the program.
With this function the hardware can selectively load data into the DATANET-30 memory. This is
used to load programs initially, as well as to reload programs on an error condition.
It
is also
used to load diagnostic programs for maintenance.
This function may be initiated in one of several ways.
1.
Manually, by pressing a push button switch on the maintenance panel.
2.
The
Q
counter counting down past zero to the hardware load value.
3.
Under program control.
[ID/A\1J/A\~~1Jc:J ~®------------
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