7090 System Make-Up - IBM 7090 Instruction-Reference

The input section of a computer system accepts information from any outside source
and places it in the storage section. This information may come from punched cards,
magnetic tape, or manually operated keys. The information may be instructions, data
(numbers for arithmetic calculations), or alphabetic characters for printing page
headings, comments, and so forth.
The storage unit accepts and stores information that com es into the system through
the input section. When any portion of the information in storage is needed, that por-
tion is located and sent out to the section that requested it. All information in the sys-
tem is at one time or another, in storage; therefore, computer speed depends on
storage speed. The storage scheme of most computer systems today is random access--
any portion of information can be located directly without searching other locations.
The arithmetic section is the calculating section of the computer system. Here,
portions of information ~ either instructions or data, can be transformed, combined,
or altered.
The control section directs the other sections. It tells them what to do and when to
do it. Instructions come into the control section from storage. The control section
also controls itself in that
it
keeps account of the instruction it is using and the one that
it will use next.
The output section takes calculated information from storage and presents it to an
outside user. Commonly used forms of output are: information on magnetic tape,
punched cards, printed reports, or indicator lights.
1. 3. 00 7090 SYSTEM MAKE-UP
The 7090 system includes all five of the sections previously mentioned. Figure
1. 3-1 shows the general grouping of these sections in the 7090 system; arrows indicate
the general flow of information. Although the functional sections can be neatly separ-
ated, in practical application it is more likely that some will be combined and others ~
separated. Input and output are combined with a portion of control in a data channel,
and arithmetic with another portion of control in the central processing unit (CPU).
Storage is the only functional section that is a separate machine unit. The mUltiplexor
controls the routing of information into and out of storage.
The arrangement shown in Figure 1. 3-1 allows input-output to operate somewhat
independently, sharing storage with CPU. The highest order of controls is in the CPU,
where control is delegated to the lower order controls in the data channel and multi-
plexor.
A representative 7090 system appears in Figure 1. 3-2; the physical grouping of
7090 functions is shown, with machine types. The tBM 7100 Central Processing Unit
is contained in two cabinets, or frames, CPU1 and CPU2. The 7151 Console Control
Unit provides manual controls for the system operated as a whole. The IBM 7606
Multiplexor and IBM 7302 Core Storage correspond to the same units shown in Figure
1. 3-1. The number of machines available for 7090 input-output
(1-0)
operations is
variable, but only seven types are ordinarily used:
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