7090 General Logic - IBM 7090 Instruction-Reference

It
is possible for a 7090 with the full eight data channels to have eight 1-0 programs
and the CPU program in operation simultaneously --each independent of the others and
all sharing core storage.
The IBM 7302 Core Storage is a fast, random-access storage unit. A unit of informa-
tion can be read into (or out of) anyone of its 32,768 storage locations in 2.18 micro-
seconds. Read-out is spoken of as being nondestructive in that the information remains
intact in core storage after read-out.- Storage serves both the CPU and data channels.
The only restriction is that no two units can be using storage at exactly the same time.
If a data channel calls for storage while CPU is using storage, the channel waits until
CPU permits. storage priority to pass to the channel.
The IBM 7606 Multiplexor is a time sharing and switching device.
It
provides a path
to and from storage for the CPU and data channels. The multiplexor also performs
certain anticipatory, or look-ahead functions associated with data channel operations.
The IBM 7151 CPU Console Control Unit provides the means to manually control the
system and to display, in indicator lights, the contents of various registers, or anyone
of the storage locations. Several registers are continually displayed. The console also
houses the C E test panel and the marginal voltage check panel.
1. 4. 00 7090 GENERAL LOGIC
The 7090 system operation can be compared to a 407 -514 summary punch operation.
The card feed in the 407 is input; storage, arithmetic, and control are in the 407; the
407 print wheels and 514 punch are output. The 514 punches a card only when instructed
to do so by the 407 and information to be punched must be in storage and wired to the 514.
The 407 waits for a signal from the 514 before proceeding to another operation. Similar
requirements for control exist in the 7090 system. Input waits in a ready status until
called for by the control section; the control section manipulates information in a pre-
determined manner and sequence; output operates when called for by the control section.
Again--as in the accounting machine, summary punch system--the control section is
continually informed of the progress of events in all sections so that another operation
can be initiated as soon as the current operation is complete.
An example of information flow and control in the 7090, is the sequence taken by the
system in solving the following problem:
Given:
Problem:
The quantities A and B punched in a card.
Add B to A and print the result, C.
(A+B
=
C, print C)
1. Cause the card reader to run and feed the card.
2. Read the information from the card and place it in storage.
3. Bring A from storage into the arithmetic section.
4. Bring B from storage and add it to A.
5. Place the result, C, in storage.
6. Cause the printer to run.
7. Bring C from storage and send it to the print wheels for printing.
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